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ELECTRONIC COMMUNICATIONS PRIVACY ACT 

(ECPA) (PART II): GEOLOCATION PRIVACY AND 

SURVEILLANCE 

HEARING 

BEFORE THE

SUBCOMMITTEE ON CRIME, TERRORISM, 

HOMELAND SECURITY, AND INVESTIGATIONS 

OF THE

COMMITTEE ON THE JUDICIARY 

HOUSE OF REPRESENTATIVES 

ONE HUNDRED THIRTEENTH CONGRESS 

FIRST SESSION 

APRIL 25, 2013 

Serial No. 113–34 

Printed for the use of the Committee on the Judiciary 

( 

Available via the World Wide Web: http://judiciary.house.gov 
(II) 

COMMITTEE ON THE JUDICIARY 

BOB GOODLATTE, Virginia, Chairman 

F. JAMES SENSENBRENNER, JR., 

Wisconsin 

HOWARD COBLE, North Carolina 

LAMAR SMITH, Texas 

STEVE CHABOT, Ohio 

SPENCER BACHUS, Alabama 

DARRELL E. ISSA, California 

J. RANDY FORBES, Virginia 

STEVE KING, Iowa 

TRENT FRANKS, Arizona 

LOUIE GOHMERT, Texas 

JIM JORDAN, Ohio 

TED POE, Texas 

JASON CHAFFETZ, Utah 

TOM MARINO, Pennsylvania 

TREY GOWDY, South Carolina 

MARK AMODEI, Nevada 

RAU ́ L LABRADOR, Idaho 

BLAKE FARENTHOLD, Texas 

GEORGE HOLDING, North Carolina 

DOUG COLLINS, Georgia 

RON DeSANTIS, Florida 

[Vacant] 

JOHN CONYERS, JR., Michigan 

JERROLD NADLER, New York 

ROBERT C. ‘‘BOBBY’’ SCOTT, Virginia 

MELVIN L. WATT, North Carolina 

ZOE LOFGREN, California 

SHEILA JACKSON LEE, Texas 

STEVE COHEN, Tennessee 

HENRY C. ‘‘HANK’’ JOHNSON, JR., 

Georgia 

PEDRO R. PIERLUISI, Puerto Rico 

JUDY CHU, California 

TED DEUTCH, Florida 

LUIS V. GUTIERREZ, Illinois 

KAREN BASS, California 

CEDRIC RICHMOND, Louisiana 

SUZAN DelBENE, Washington 

JOE GARCIA, Florida 

HAKEEM JEFFRIES, New York 

SHELLEY HUSBAND, Chief of Staff & General Counsel 

PERRY APELBAUM, Minority Staff Director & Chief Counsel 

SUBCOMMITTEE ON CRIME, TERRORISM, HOMELAND SECURITY, AND INVESTIGATIONS

F. JAMES SENSENBRENNER, JR., Wisconsin, Chairman 

LOUIE GOHMERT, Texas, Vice-Chairman 

HOWARD COBLE, North Carolina 

SPENCER BACHUS, Alabama 

J. RANDY FORBES, Virginia 

TRENT FRANKS, Arizona 

JASON CHAFFETZ, Utah 

TREY GOWDY, South Carolina 

RAU ́ L LABRADOR, Idaho 

ROBERT C. ‘‘BOBBY’’ SCOTT, Virginia 

PEDRO R. PIERLUISI, Puerto Rico 

JUDY CHU, California 

LUIS V. GUTIERREZ, Illinois 

KAREN BASS, California 

CEDRIC RICHMOND, Louisiana 

CAROLINE LYNCH, Chief Counsel 

BOBBY VASSAR, Minority Counsel 
(III) 

C O N T E N T S 

APRIL 25, 2013 

Page 

OPENING STATEMENTS 

The Honorable F. James Sensenbrenner, Jr., a Representative in Congress 

from the State of Wisconsin, and Chairman, Subcommittee on Crime, Terrorism, Homeland Security, and Investigations ................................................ 1 

The Honorable Robert C. ‘‘Bobby’’ Scott, a Representative in Congress from 

the State of Virginia, and Ranking Member, Subcommittee on Crime, Terrorism, Homeland Security, and Investigations ................................................ 2 

The Honorable John Conyers, Jr., a Representative in Congress from the 

State of Michigan, and Ranking Member, Committee on the Judiciary ......... 3 

WITNESSES 

Mark Eckenwiler, Senior Counsel, Perkins Coie LLP 

Oral Testimony ..................................................................................................... 6 

Prepared Statement ............................................................................................. 8 

Peter A. Modaferri, International Association of Chiefs of Police 

Oral Testimony ..................................................................................................... 19 

Prepared Statement ............................................................................................. 21 

Catherine Crump, Staff Attorney, American Civil Liberties Union (ACLU) 

Oral Testimony ..................................................................................................... 29 

Prepared Statement ............................................................................................. 31 

Matt Blaze, Professor, University of Pennsylvania 

Oral Testimony ..................................................................................................... 43 

Prepared Statement ............................................................................................. 45 

LETTERS, STATEMENTS, ETC., SUBMITTED FOR THE HEARING 

Prepared Statement of the Honorable John Conyers, Jr., a Representative 

in Congress from the State of Michigan, and Ranking Member, Committee 

on the Judiciary ................................................................................................... 4 

APPENDIX 

MATERIAL SUBMITTED FOR THE HEARING RECORD

Material submitted by the Honorable Robert C. ‘‘Bobby’’ Scott, a Representative in Congress from the State of Virginia, and Ranking Member, Subcommittee on Crime, Terrorism, Homeland Security, and Investigations ...... 72 

Questions for the Record submitted to Mark Eckenwiler, Senior Counsel, 

Perkins Coie LLP ................................................................................................. 152 

Response to Questions for the Record from Peter A. Modaferri, International 

Association of Chiefs of Police ............................................................................. 155 

Questions for the Record submitted to Catherine Crump, Staff Attorney, 

American Civil Liberties Union (ACLU) ............................................................ 158 

Response to Questions for the Record from Matt Blaze, Professor, University 

of Pennsylvania .................................................................................................... 161 

(1) 

ELECTRONIC COMMUNICATIONS PRIVACY 

ACT (ECPA) (PART II): GEOLOCATION PRIVACY AND SURVEILLANCE 

THURSDAY, APRIL 25, 2013 

HOUSE OF REPRESENTATIVES

SUBCOMMITTEE ON CRIME, TERRORISM, HOMELAND SECURITY, AND INVESTIGATIONS

COMMITTEE ON THE JUDICIARY

Washington, DC. 

The Subcommittee met, pursuant to call, at 10 a.m., in room 

2141, Rayburn House Office Building, the Honorable F. James Sensenbrenner, Jr. (Chairman of the Subcommittee) presiding. 

Present: Representatives Sensenbrenner, Goodlatte, Scott, Conyers, Chu, and Richmond. 

Staff Present: Anthony Angeli, Majority Counsel; and Joe 

Graupensperger, Minority Counsel. 

Mr. SENSENBRENNER. The Subcommittee will come to order. 

Without objection, the Chair will be authorized to declare recesses 

during votes today. 

This hearing is the second in a series on the Electronic Communications Privacy Act, otherwise known as ECPA. Today, we will 

examine the issue of geolocation and its use by law enforcement in 

criminal investigations. 

While this hearing was planned before the attack in Boston, 

those tragic events highlight the importance of the topic. The 

stakes are high. As in any ECPA reform, Congress needs to strike 

the right balance to protect privacy rights without undermining 

law enforcement. 

The term ‘‘geolocation’’ is often used broadly and in a variety of 

contexts. Geolocation refers to the method of assessing the location 

of an electronic device—typically a cell phone, but sometimes a vehicle—with or without a tracker or a computer. 

Geolocation is often related with the acquisition of cell tower information to determine the general location of a cell phone. Thus, 

frequently, geolocation is related to the use of global positioning 

systems, or GPS. 

The results from its use often vary. Depending upon the type of 

cell phone being tracked or the provider on whose network it operates, the information about a phone’s location can vary from a city 

block to specific latitude and longitude coordinates. 
2 

The primary objective of this hearing is to examine whether the 

electronic acquisition of a device’s geographical location is covered 

by the Fourth Amendment and, if so, what level of legal process 

should be required before accessing such information. The hearing 

will also examine how law enforcement makes use of this information and its importance in their response to criminal and national 

security threats. 

ECPA has not kept pace with the assortment of new communication devices and other technologies that are now widely available 

in today’s marketplace. This is particularly true with geolocation 

technology. As GPS technology has become cheaper, more widely 

available, and used more frequently in our daily lives, the legal authorities and restrictions that are or should be in place to govern 

when and where such information is accessed and used have become less clear. 

No one doubts that geolocation information is useful, especially 

to law enforcement officers and agents. The larger question is how 

do we balance the needs of law enforcement with the expectations 

of privacy of those they are charged with protecting? 

In U.S. v. Jones, the Supreme Court proposed that new intrusions on privacy may spur the enactment of legislation to protect 

against these intrusions, as had occurred in the case of wiretapping 

many years ago. The court asserted that Congress should enact a 

comprehensive statute regulating the use of GPS tracking technology for law enforcement purposes. 

Since all geolocation capabilities are not created equal, our task 

in enacting comprehensive legislation is more complex. Unfortunately, Jones was limited to the installation of a GPS tracker on 

a suspect’s vehicle and gives us limited guidance. 

I am dismayed to point out that the Department of Justice declined to testify at today’s hearing. I was tempted to have an empty 

chair for their witness, should they change their mind at the last 

minute. There is not an empty chair at the witness table, but the 

chair notes that there are plenty of empty chairs in the room, 

should they decide to appear. 

As the Nation’s most frequent user of ECPA for geolocation purposes, the department is in a unique position to educate the Members of this Subcommittee on the status of Federal law and the department’s current practices when seeking court orders for 

geolocation information. While DOJ has briefed Committee staff on 

ECPA and geolocation, the Obama administration has refused our 

request to testify in public because it lacks a clear policy position 

on how best to reform ECPA. 

This is unacceptable, and I don’t want to spend a lot of time 

working on something that is workable when, all of a sudden, out 

of the blue there will be a statement of Administration policy that 

will threaten a veto over hours of work and input from everybody 

except the Department of Justice. We must, unfortunately, move 

forward in their absence. 

I welcome our witnesses who are with us today and look forward 

to their testimony and now recognize the gentleman from Virginia, 

Mr. Scott, the Ranking Member. 

Mr. SCOTT. Thank you, Mr. Chairman. 
3 

Mr. Chairman, today we meet to discuss issues related to 

geolocation, privacy, and surveillance and the need to clarify the 

standards of Government access to certain types of personal location information. 

Technology affords us greater conveniences, but advances in 

technology present new challenges to our privacy rights. Much 

more information is generated about us, and we are presented with 

questions about how it is stored and by whom it may be accessed. 

The Supreme Court 1967 decision Katz v. United States continues to direct our privacy jurisprudence. In that case, a man’s 

calls from a public pay phone booth were recorded by a device attached to the outside of the booth by the FBI. The court ruled that 

this eavesdropping was a search under the Fourth Amendment because it violated a man’s ‘‘reasonable expectation of privacy.’’ 

Now that standard should continue to guide us today. When we 

go somewhere in public, we know that we may be seen by others, 

and even if we do not want others to know where we are, the visual recognition by others is a risk we take. What we do not expect 

is that our carrying of a personal communication device, such as 

a cell phone, will be used by Government to track and record our 

every move. 

This is particularly the case as cell site location information has 

become, in many cases, as accurate as GPS because of the growing 

number of cell sites and the use of microcells that cover extremely 

small areas. We have laws that make a combination between privacy rights and sometimes urgent need of law enforcement to investigate crimes, and that is why Congress drafted Federal statutes to restrict Government access to the content of electronic communications but provides a less stringent standard for accessing 

noncontent records reflecting just that a communication took place, 

but not the content of the communication. 

The Electronic Communications Privacy Act, which was enacted 

in 1986, was forward looking in some ways but did not contemplate 

every possible technological advance. Because the statute did not 

foresee the current state of location technology, the law does not 

provide clear guidance as to what steps the Government must take 

in order to obtain location data from devices like cell phones and 

navigation systems in cars. 

While we should have exceptions for emergency situations and 

situations where the need to locate a missing person—where there 

may be a need to locate a missing person, we need legislation to 

address the lack of clarity in the law by generally requiring the 

Government to show something, possibly probable cause, to get a 

warrant in order to obtain historical and prospective data location 

about our citizens. 

Given our expectation of privacy, this should be the starting 

point for our discussion of the issue today. 

I yield back the balance of my time. 

Mr. SENSENBRENNER. I thank the Ranking Member. 

The Chair now recognizes the most recent Chairman emeritus of 

the Committee, the gentleman from Michigan, Mr. Conyers, for his 

opening remarks. 

Mr. CONYERS. Thank you, Chairman Sensenbrenner and Ranking Member Scott. 
4 

I will put my statement in the record and indicate my support 

and co-sponsorship of H.R. 1312 and warmly welcome the witnesses that are joining us here today. 

This question of cell phones and tracking locations are right 

smack up against the privacy considerations, and this discussion 

and this legislation will be very important in that direction. 

And so, I am happy to join all of you at this hearing, and I return 

the balance of my time. 

[The prepared statement of Mr. Conyers follows:] 

Prepared Statement of the Honorable John Conyers, Jr., a Representative 

in Congress from the State of Michigan, and Ranking Member, Committee on the Judiciary 

Today we consider a critical issue of personal privacy: whether the government 

should have to show probable cause and get a warrant in order to obtain from wireless devices information about where someone has been or is going. This is particularly important because the ACLU has reported the widespread use of 

cell phone tracking by law enforcement agencies and revealed that the 

legal standards used to engage in tracking vary widely. 

I want to make several points about this issue and what we must do. 

First, government tracking of everywhere we go is contrary to our reasonable expectation of privacy. Today, almost all of us carry cell phones or 

other electronic devices, but we do so in order to communicate with each 

other, not to be tracked by the government. Geolocation tracking, whether information about where we have been or where we are going, strikes at the heart 

of personal privacy interests. 

The pattern of our movements reveals much about ourselves. When individuals 

are tracked in this way, the government is able to generate a profile of a person’s 

public movements that includes details about a person’s familial, political, professional, religious, and other intimate associations. 

Next, we must recognize that the Supreme Court’s decision last year in 

U.S. v Jones reinforces the fact that the question of location privacy in the 

hands of Congress. In Jones, the court ruled that placing a GPS tracking device 

on a car constitutes a search under the Fourth Amendment. 

While the Court was not presented with the question of whether a warrant should 

be required or under what standard a court order should be issued, the case highlights the need for us to address the full range of location tracking issues. 

In his concurring opinion, Justice Alito noted that the availability of location 

tracking devices, including cell phones, raises important questions about our expectations of privacy. He noted that Congress has not adequately addressed these 

issues and that ‘‘in circumstances involving dramatic technological change, the best 

solution to privacy concerns may well be legislative.’’ 

Finally, I propose that we enact legislation to address uncertainty in the law and 

provide the appropriate standard. Current law does not adequately address this 

issue and we need to enact H.R. 1312, the ‘‘Geolocation Privacy and Surveillance 

Act.’’ 

I am a cosponsor this bill, introduced by Congressman Jason Chaffetz to require 

the government to obtain a warrant based on probable cause to compel cell phone 

companies to disclose the location information of their customers. 

As the New York Times reported, ‘‘lawyers and law enforcement officials agree[] 

that there [is] uncertainty over what information the police are entitled to get legally from cell phone companies, what standards of evidence they must meet, and 

when courts must get involved.’’ 

Protecting the privacy of this information is up to Congress, and given the reasonable expectations of privacy we have about our location information, the appropriate 

standard is probable cause. That is why I support enactment of H.R. 1312. 

Thank you. 

Mr. SENSENBRENNER. I thank the distinguished Chairman emeritus. 

By tradition, we swear witnesses in at the beginning of each 

hearing. So will the witnesses please rise, raise your right hand? 
5 

[Witnesses sworn.] 

Mr. SENSENBRENNER. Let the record show that each of the witnesses answered in the affirmative, and the Chair will now introduce the witnesses. 

Mr. Mark Eckenwiler is senior counsel of the firm Perkins Coie. 

His focus is in electronic privacy law, civil and criminal liability for 

online conduct, computer intrusions, and service provider interactions with law enforcement. Mr. Eckenwiler previously served 

with the Department of Justice as a primary authority on Federal 

electronic surveillance law, including the Wiretap Act, the pen register/trap and trace statute, the Electronic Communications Privacy Act of 1986, and CALEA. 

Most recently, he was the Associate Director for Technology with 

the Office of Enforcement Operations in the Justice Department’s 

Criminal Division, where he oversaw all Federal applications for 

Internet communications surveillance orders. 

He received his bachelor’s of arts degree from Harvard, his master of arts from Boston University, and his law degree from NYU 

School of Law. 

Mr. Peter Modaferri has been a detective with the Rockland 

County District Attorney’s Office for over 40 years and the last 25 

years as chief of detectives. Since 1990, Mr. Modaferri has chaired 

the Investigative Operations Committee for the International Association of Chiefs of Police. He is a member of the Criminal Intelligence Coordinating Council and served as a regional expert for 

the Office of National Drug Control Policy Technology Transfer 

Program and consulted with the Foreign Terrorism Tracking Task 

Force, which was established in 2001. 

Mr. Modaferri is a graduate of the FBI National Academy, holds 

a B.A. from Siena College, and a master of arts in criminal justice, 

and has concluded the coursework in the doctoral program at the 

City University of New York. In 1992, he was awarded a Fulbright 

Fellowship for graduate study in the United Kingdom. 

Ms. Catherine Crump currently serves as a staff attorney for the 

American Civil Liberties Union Speech, Privacy, and Technology 

Project. She is currently litigating constitutional challenges to cell 

phone tracking by law enforcement and is seeking information related to the Justice Department interpretation of how United 

States v. Jones applies to its location tracking activity. 

If you find that out, please let us know because, apparently, they 

don’t want to tell us directly. 

She has directed nationwide requests for public records regarding 

law enforcement’s use of cell phone information and license plate 

readers. She received her bachelor of arts from Stanford University 

and her law degree from Stanford Law School. 

Mr. Matthew Blaze is Associate Professor of Computer and Information Science at the University of Pennsylvania. Mr. Blaze’s research focuses on cryptography, mass applications, trust management, human scale security, secure systems design, networking, 

and distributed computing. His focus is in security technology with 

bearing on public policy issues, including cryptology policy, wiretapping, and surveillance. 
6 

He received his bachelor of science degree from City University 

of New York, Hunter College; his master of science degree from Columbia; and his master’s of art and Ph.D. from Princeton. 

Each of the witnesses’ written statements will be entered into 

the record in its entirety, and I ask that each summarize his or her 

testimony in 5 minutes. We have the lights there. The yellow light 

means you should speed up, and the red light means you should 

stop. 

Mr. Eckenwiler? 

TESTIMONY OF MARK ECKENWILER, SENIOR COUNSEL, 

PERKINS COIE LLP 

Mr. ECKENWILER. Chairman Sensenbrenner, Ranking Member 

Scott, Mr. Chairman Emeritus, and distinguished Members of the 

Subcommittee, thank you for your invitation to testify this morning 

on the important topic of cell phone location privacy. 

My name is Mark Eckenwiler, and I should state at the outset 

that my comments today reflect only my personal views. I will, of 

course, be drawing on my 16 years of experience working on a daily 

basis with the Electronic Communications Privacy Act, or ECPA. I 

am not speaking today on behalf of the Justice Department or my 

current employer or any individual client. 

My testimony today focuses on both the types of location data 

that law enforcement seeks from wireless providers and the legal 

rules that restrict such disclosures. I have three main points. 

First, not all location data is the same. It can be generated in 

a variety of ways, and one type of location data, cell site location 

information, is less precise than others. Second, in general, existing 

law provides a carefully calibrated set of meaningful protections for 

wireless user location data. The sky is not falling. And third, the 

current framework does, however, have some gaps and inconsistencies that I think would benefit from careful study by this Committee. 

Now I mentioned that there are different types of location data. 

Cell site information is generated in the ordinary course of business whenever a user sends or receives a phone call or a text message. It does not provide pinpoint location information for a phone. 

Rather, these records indicate which cell tower handled a particular communication. 

Because tower spacing varies widely across a range of locations 

from rural to suburban to urban settings, so does the area covered 

by each tower. And as a result, cell site location information may 

place a phone on a given city block, or it may only indicate a very 

large area of several square miles in which a phone was apparently 

located at the time of a communication. 

Contrast this with precise location information. This separate 

class of data, which includes but is not limited to GPS, is different 

not only in its level of precision and, thus, its privacy invasiveness, 

but also how it is obtained. One significant difference is that precise location information may be generated even when the phone 

is not in active use, sending or receiving a communication. 

Existing law treats these two types of information, cell site and 

precise location information, very differently. Under ECPA, law enforcement can obtain stored cell site records—that is, for some pe-
7 

riod in the past—only by applying to a court for a so-called 2703(d) 

order. 

Now the standard for issuance of this, specific and articulable 

facts, is an important safeguard, and indeed, the executive director 

of the Electronic Frontier Foundation testified before a joint House/ 

Senate committee this standard affords ‘‘a high degree of protection.’’ 

The rules governing prospective collection of cell site information—that is, real-time collection—are a subject of profound disagreement among the Federal courts. Some of them apply this 

same 2703(d) standard in granting so-called ‘‘hybrid orders.’’ Others see a gap in the statute and have required a warrant because 

there’s no other available mechanism. 

Because precise location information, by contrast, is not collected 

by wireless carriers in the ordinary course, it is not typically available as a stored record for past periods. For ongoing surveillance, 

ECPA provides no clear statutory mechanism, and as a result, the 

practice at the Federal level has been to seek a search warrant 

under Criminal Rule 41, based upon a showing of probable cause. 

Finally, as set out in more detail in my written statement, the 

current legal framework is not perfect. There are a number of 

issues that merit this Committee’s attention, and I would be 

pleased to discuss those in greater detail during the Q&A. 

In summary, Mr. Chairman, existing law, especially ECPA, recognizes the important privacy interests at stake by putting meaningful legal barriers between law enforcement and users’ location 

data. In doing so, current law takes the approach of careful calibration of legal standards rather than one size fits all. 

Thank you for the opportunity to appear this morning. I look forward to your questions. 

[The prepared statement of Mr. Eckenwiler follows:] 
8 

Before the 

Committee on the Judiciary 

Subcommittee on Crime, Terrorism, 

Homeland Security, and Investigations 

United States House of Representatives 

The Electronic Conmmnications Privacy Act (ECPA), Part 2: 

Geolocation Privacy and Surveillance 

April 25, 2013 

Statement of 

Mark Eckenwiler 

Senior Counsel 

Perkins Coie LLP 
9 

1. INTRODUCTION 

Chairman Sensenbrenner, Ranking Member Scott, and distinb'llished members of the 

Subcommittee, thank you for convening this hearing. It is an honor to appear before you today to 

discuss the important legal and technical issues raised by law enforcement access to wireless user 

location data. 

Let me say at the outset that these comments reflect my personal views. T am not speaking for or 

on behalf of any client or group of clients, nor for my former colleab'lles at the Department of 

Justice. Instead, I offer my personal observations, drawn from over 16 years of working with the 

Electronic Communications Privacy Act (ECPA) while with the Justice Department and, more 

recently, in the course of representing service providers in private practice. 

II. TYPES OF LOCATION DATA A V AILABLE FROM WIRELESS CARRIERS 

To understand the issues surrounding law enforcement access to carrier-held location data, it is 

essential to start with the technology, not the law. Law enforcement typically seeks two distinct 

types oflocation data from wireless carriers: cell-site location information and precision location 

data. 

A Cell-Site Location Information (CSLI). As you know, cellular providers rely upon a 

network of antennas to provide service across large coverage areas. Whenever a user places or 

receives a voice call (or sends or receives a text message), the radio portion of that 

communication is transmitted between the customer's handset and a nearby tower. If the user 

moves in the course of a voice call-such as when traveling on the highway-the call may be 

seamlessly "handed off' to one or more other towers in sequence as the handset moves through 

different coverage areas. 

Spacing between towers is determined primarily by the amount of network activity (and thus by 

the number of users) in a given area. Tn sparsely populated regions, cell towers are widely 

spaced, with each typically serving a coverage area several miles in radius. In suburban areas 

with moderate population density, carriers place towers closer together, with each having a 

service radius of a mile or less. Antennas in center cities are clustered even more tightly, with 

cell towers in the most densely populated areas (such as midtown Manhattan) spaced every 200 

meters or less. 

In suburban and urban areas, the coverage area for a given cell tower is typically subdivided into 

multiple sectors (or tower "faces"). In these cases, there are typically three l20-degree sectors, 

each with its own antenna. (To visualize this contiguration, imagine a clock face divided into 

thirds from 10 to 2, 2 to 6, and 6 to 10. Each "pie slice" represents the coverage area for a given 

antenna.) Towers in sparsely populated areas, by contrast, normally have a single 

omnidirectional antenna. 

Whenever a user places or receives a voice call (or sends or receives a text message), the 

network handling that communication-which may be the customer's home network, or another 

network with which the customer's carrier has a roaming agreement-creates a record of the tirst 

cell tower that handles the call or text message. Tfthe tower coverage area is divided into 

multiple sectors, the stored cell-site location information (CSLI) record also indicates which 

- 1 -
10 

particular antenna handled the communication. Most, but not all, carriers also record the last 

tower (and, where applicable, sector) handling a voice call. Because text messages are short, and 

thus are transmitted almost instantaneously, they pass through only a single antenna. 

The degree to which CSLl reveals the location of a user's phone varies for several reasons. First, 

these records do not provide grid coordinates for the phone itselt; rather, they indicate which 

nearby antenna transmitted a communication associated with that handset. Because tower 

spacing varies enormously, the radius of corresponding tower coverage does as well, and 

therefore the projected area from where a call was placed will likewise vary. 

In heavily populated urban areas, CSLl can-subject to the further limitations discussed belowplace a handset in an area of approximately 1,000 square meters. In suburban areas with towers 

spaced further apart, CSLl may suggest an area ofa square mile or more. Tower data from rural 

areas, by contrast, provides only very broad location data often covering dozens of square miles 

or more. 

Other factors also contribute to the general imprecision ofCSLl. For example, the boundaries 

between the sectors of an individual cell tower, as well as the boundaries between areas served 

by different towers, are neither precise nor tixed. Records showing communications activity 

alternating between two adjacent coverage areas may indicate handset movement back and forth 

between the areas, or may instead result from the activity of a non-moving user in an area of 

overlapping coverage. 

More importantly, a particular communication is not always handled by the closest tower. Both 

natural terrain features (e.g., hills and valleys) and man-made structures interfere with line-ofsight radio transmission. Weather conditions, including precipitation or even humidity level, also 

may affect signal propagation. 

At times, the carrier antenna closest to the user's handset may even be entirely unavailable. This 

can result from local, temporary equipment or network outages, or simply from network 

congestion For example, when highway traffic backs up at a toll plaza or accident scene, the 

nearest tower's capacity may be saturated by unusually high activity levels. In these 

circumstances, the next user trying to make a call may only be able connect to a more distant, 

less burdened tower; the resulting CSLl record will indicate usage of the latter, creating the 

misleading impression that the handset was closer to that tower than to any other. 

- 2-
11 

Tower I (witll mllltiple 

aDleDus/5ecton) 

Tower 1 ( .. it~ m"ltiple 

aIleUl,.slsecton ) 

Figure I 

______ Con,n lle SKlor of 

aanailable Uleaaa 

Norma' cO\·enge 

---,'<""r-- sector of adinelll 

lower 

In Fi!:lllre I above. the star rcopre$Cnls a hypothelical handset IOC3lion: Iht' dark area represents Ihe 

nomla1, hUI tempornrily unavailable. covl'11lge area for Ihe closest anlenna on Tower I; and the 

lighl gray area depicts Ihe nomlal coverage area for an adjllcent tower's sector. Activity handled 

by To\\'er 2 would creale a record tt.'socialing Ihe handsel willt Ihe lighl gray area. even though 

the phone WIIS outside Ihal sector and closer to Tuwer I. 

Some commemators assen that the increasing use of··microcells·· with smal ler cov~ra!!.e areas 

renders CSU functionally equiva lent to GP$ or other more precise localiO(l tecbnologies These 

claims ~re misleading U!.er-owned microcells - such as Ihose purchased and installed by home 

Cllstomers - do not expand the network of lowers available 10 the general populmion, Ralher. 

these microcells are usable only by their owners. and Ihereforecannol pro\'ide service to. let 

alone identify Ihe location of, the millions of other cell phone u~efS. 

• real-time (prospective) coll ection and 3a:ess to historical records: 

• communications content and non-content records, and 

• IrJnsaclional non-<:ontenl records and mon; limited subscriber fecQfds. 

Depending on the type of infommtion sought and the manner in which il is to be CQllectcd, 

ECPA requires varying forms of compulsory process. These range from subpoenas-issued by d 

-3 -
12 

prosecutor (or, in some cases, an investigative agency) on the comparatively low standard of 

relevance--up through various types of increasingly demanding court orders-with wiretap 

orders (based on probable cause and other special requirements) at the other end of the spectrum. 

I. Access 10 Stored CSU 

As originally enacted in 1986, ECPA allowed the government to obtain any stored non-content 

record about a communications provider's customer using a grand jury, trial, or administrative 

subpoena. As part of the 1994 Communications Assistance for Law Enforcement Act (CALEA), 

however, Congress amended ECPA to divide non-content records into two categories. 

The first of these categories, often referred to informally as "basic subscriber information," 

remains available in response to a subpoena. 1 These records-explicitly enumerated in an 

exhaustive list of six categories-include the customer's name, address, account identitler, 

length of service, and method of payment. Except for "local and long distance telephone 

connection records, or records of session times and durations," however, this category does not 

include records about specific user activity 

Instead, when law enforcement seeks to compel a service provider to disclose other stored noncontent records, it must apply for a unique type of court order that was created in the 1994 

amendment to ECP A 2 To obtain this so-called "2703( d) order" (named for the section of the 

statute where it resides), the government must 

offer[] specific and articulable facts showing that there are 

reasonable grounds to believe that. the records or other 

information sought, are relevant and material to an ongoing 

criminal investigation. 

As explained in the report from this Committee, "[t]he intent of raising the standard for access to 

transactional data is to b'llard against 'fishing expeditions' by law enforcement.,,3 Advocating 

strongly in favor ofthis raised standard during an August 11, 1994 joint House-Senate 

committee hearing on the legislation,4 the Executive Director of the Electronic Frontier 

Foundation described the proposal as follows: 

Chief among these new protections is an enhanced protection for 

transactional records from indiscriminate law enforcement access. 

1 See 18 U.S.C. ~ 27m(c)(2). 

, See § 2703(d). 

3 H. Rep. No. 827. IOJd Cong .. 2d Sess .. at 31 (Oct. 4,1994). 

1 f)igiial 'f'elephony and I.enr r)l/hrcemenl.1cces.",' to .'Idvanced telecommunications technologies and S'ervice,,,,', 

1994: Joint Ifearings on lI.N -1922 and S'. 2375 IJefhre Lhe Suhcomm. on Techn%KV and the I.aw (?flhe .)'enale 

Comm. on Lhe Judiciary and Lhe 5,'uhcomm. on Civil and Cons/itl/tional RighI.'\' (?flhe l/ouse Comm. on the Judicia"..v, 

1 md Cong .. 2d Scss. 160-61 (1994) (prepared statement or JelTV J. Bennan, Executive Director, Electronic Frontier 

Foundntion). 

- 4-
13 

... Provisions in the bill recognize that this transactional 

information created by new digital communications systems is 

extremely sensitive and deserves a high degree of protection from 

casual law enforcement access which is currently possible without 

any independent judicial supervision. 

In order to gain access to transactional records ... law enforcement 

will have to prove to a court, by the showing of "specific and 

articulable facts" that the records requested are relevant to an 

ongoing criminal investigation. This means that the government 

may not request volumes of transactional records merely to see 

what it can find through traffic analysis. Rather, law enforcement 

will have to prove to a court that it has reason to believe that it will 

tind specitic infonnation relevant to an ongoing criminal 

investigation in the records it requested. 

Court order protection will make it much more dim cult for law 

enforcement to go on "fishing expeditions" through online 

transactional records, hoping to find evidence of a crime by 

accident. 

The most important change that these new provisions offer is that 

law enforcement will: (a) have to convince a judge that there is 

reason to look at a particular set of records, and; (b) have to expend 

the time and energy necessary to have a United States Attorney or 

District Attorney actually present a case before a court. 

An overwhelming majority of courts, including the federal Third Circuit Court of Appeals, has 

found that historical "CSLI from cell phone calls is obtainable under a § 2703(d) order.,,5 

Although a handful oflower courts have held that section 2703(d) does not apply to stored CSLI, 

this view has failed to win broader acceptance. 6 Many of these same lower court judges have 

also arb'lled that historical CSLI is protected by the Fourth Amendment, and that a warrant is 

therefore necessary to compel such third-party records. Here, too, this represents a minority 

position; so far as I am aware, no federal court has ever granted a motion to su~press CSLI on 

these or any other grounds, despite attempts by numerous criminal defendants. 

5111 re .ipplicalioll, 620 F.3d 30~, 313 Od Cir. 2(10). 

6 Courts adopting this minority vicw point to the exclusion or"any communication rrom a tracking dc\'icc (as 

defined in section 3117 orthis title)" rrom ECPA's definition, at 18 U.S.c. § 2510(12)(C), or "electronic 

communication." (As noted by the Third Cirenit this view fails to distinguish between a eonununieation itselfsuch as a phone eall- and data aboul the communication. such as CSLI.) The minority view has the perverse 

consequence or excluding CSLI entirely rrom ECPA 's protections, meaning tlmt the govenunent could compel CSLI 

using lesser compulsory process such as a subpoena. 

See, e.g, lilliled SlaWS j'. Graham, 8~6 F. Supp. 2d 38~ (D. Md. 201 2) (rinding no Fourth Amendment interest): 

see also UniledSlalesv . .folles. 2012 WL 6443136 at *5 & n.9 (D.D.C. Dec. 14,2(12) (collecting cases). 

- 5 -
14 

2. Prmpective Collection oj'CSLI 

CSU acquired in real time is qualitatively the same (and thus its value is subject to the same 

practical limitations) as historical CSU. The rules governing real-time government acquisition of 

CSLI from wireless carriers are, however, much less clear. 

The pen register statute permits the government to obtain a court order authorizin~ ongoing 

collection of non-content "dialing, routing, addressing, or signaling information," information 

that would normally include CSLl. However, CALEA states that 

with regard to information acquired solely pursuant to the authority 

for pen registers and trap and trace devices (as defined in section 

3127), such call-identifying information [delivered by a carrier to 

the government] shall not include any information that may 

disclose the physical location of the subscriber (except to the 

extent that the location may be determined from the telephone 

number). 9 

This restriction creates a gap in the statutory framework: although it declares which type of 

process may not be used (i.e., a bare pen register order), it does not prescribe the types of court 

orders that may be used. (Moreover, the other major federal statute governing real-time 

surveillance-the far more demanding Wiretap Act-does not apply because it regulates only the 

collection of communications contents. 10) 

Tn an effort to t11l this gap, prosecutors began to apply for court orders under the combined 

authority of the pen register statute and section 2703(d) (which, as discussed above, requires a 

higher showing) on the grounds that such orders are not "solely pursuant" to pen register 

authority. Beginning in 2005, however, lower court judges started to reject these so-called 

"hybrid" orders. While some of these courts based their objections on obvious 

misunderstandings of the technology and kinds of data involved, 11 others reasoned that section 

2703(d)-located in the Stored Communications Act, 12 and lacking provisions that address 

duration and other aspects of real-time surveillance-could not be used to collect information 

prospectively. These courts concluded that the government needs to use a search warrant, not 

8 18 US.C § 3127(3). 

9 -l7 U.S.C § 1002(a)(2). 

lU See 18 U.S.c. §§ 2510(4) (defining "intercept" to mean "the auml or other acquisition of the contents" ofa 

protected communication) & 251 O(X) (defining "contents" to mean "any infonnation conccming the substance, 

purport. or meaning of [a] conmmnication"). 

1I The most obvious e,ample of this phenomellOn is In re .·ipp/icaliol1. 402 F. Supp. 2d 597 (D. Md. 2(05). in which 

the court confuses CSLI with GPS data. See id. at 599. 

1: Chapter 121 of Title 18 is entitled "Stored Wire and Electronic C.onnnunieations and Tmnsactioml Records 

Access." 

- 6-
15 

because the Fourth Amendment requires it, but rather because a search warrant is the only 

available mechanism. 13 

Courts remain sharply divided on this question, with practices varying from district to district 

(and, in some cases, from one judge to another within a single federal district). Even courts 

endorsing the hybrid theory have called upon Congress to resolve the issue. 14 

C. Precision Location Infonnation CPU). Beginning in 1997, the FCC adopted regulations 

requiring cellular carriers to be able to locate wireless 911 callers. Phase I of this rulemakingknown as Enhanced 911 or simply E-911-required carriers to be able to deliver a 911 caller's 

cell-site and sector information (i.e., CSLl) to the "public safety answering point" (i.e., the 911 

call center). Because of the inherent limits on the precision ofCSLl, E-911 Phase 11 (in effect 

today) requires carriers to be able to deliver more precise location information. 

In imposing these obligations, the FCC pennitted carriers to choose either of two different 

methodologies for complying: 

1. Handset-based location technology relying on special hardware or software in the 

mobile phone itself U.S carriers opting for such a "handset solution" have chosen to use 

Global Positioning System (GPS) technology, in which the phone calculates its position 

based on signals received from overhead GPS satellites. 

2. Network-based location technology in which the work of calculating a phone's position 

occurs not on the handset, but rather in the carrier's network. This "network solution" 

typically involves measuring the time required for a test signal to travel between the 

handset and detection devices on cell towers in the vicinity. Using the known locations of 

those towers and the different timing infonnation, software in the carrier's network is 

able to calculate a position for the phone. (This process, technically known as 

"multilateration," is often referred to informally as "triangulation.") 

Generally speaking, the regulations require such E-911 Phase II location information to be 

accurate to within 50-300 meters. I; 

Contrary to popular belief, carriers do not collect these types of precise location infonnation 

(PU) on consumer-level users in the ordinary course ofbusiness. 16 As a result, historical PU 

from these technologies is not available to law enforcement. 

l' Typical of this line of cases is In re Application, 497 F. Sllpp. 2d 301 (D.P.R. 2007). 

14 See In re .~pp!ication, 632 F. Supp. 2d 202. 211 (E.D.N.Y. 2008) ("District courts across the country are divided 

on an issue that requires balancing the Gm'crmncnl's invcsligatol)' needs \-vHh citil:cnsl right to privacy. Absent 

clarity from Congress_ tillS division and inconsistency in outcomes ,,,ill continue because the issue is one about 

which reasonable judges can, and obviously do, disagree."): In re Application. 460 F. Sllpp. 2d 448. 450 (SD.N.Y. 

2(06). 

15 The applicable regulation (47 C.F.R. ~ 20.18(h)) lays out a complex set or criteria. including several deadlines ror 

compliance across increased geographic areas. In general, handset-solution phone location data must be morc 

precisc t11.1n nChvork-solution data. 

- 7 -
16 

However, law enforcement may nevertheless seek PLI on a prospective basis. Because ECP A 

itself provides no clear mechanism for compelling this type of information, it is common for 

prosecutors to obtain a search warrant under Federal Rule 41 or a state equivalent. In doing so, 

some prosecutors rely on the explicit "tracking device" provisions of Rule 41, while others rely 

upon the Rule's well-established history of use as a general means of conducting ongoing 

evidence collection. 17 These may appear either in the form of stand-alone warrants, or as 

supplemental authority incorporated into a wiretap order. 18 

TTl. ISSUES DESERVING CONGRESSIONAL ATTENTION 

As suggested above, there are several areas in which the current legal framework is not entirely 

satisfactory. These include the following: 

Hybrid orders. Easily the source of greatest controversy, the government's use of hybrid 

orders-i.e., court orders combining the authority of the pen register statute and the 

"specific and articulable facts" test of section 2703(d) -has led to a sharp divide among 

lower federal courts. Greater clarity in this area would be an enormous benefit to the 

service provider community; providers have a substantial interest in knowing with 

certainty the boundaries of what is lawful, in protecting their customers' privacy, and in 

avoiding potential civil liability. 

2. "Tower dumps". Instead of seeking historical CSLI for the identitled phone of a specitic 

target, prosecutors sometimes use a section 2703(d) order to seek all records associated 

with calls handled by a given tower for a specified interval of time (usually 

corresponding to the date and time of an unsolved crime). These so-called "tower dumps" 

can be essential to identifying suspects in certain kinds of crimes such as bank 

robberies, 19 but almost invariably involve disclosure of large numbers of user records. 

The volume of information varies enormously according to time of day, the size of the 

16 Many carriers do. however, offer so-called "fleet management" services to business customers at additional cost. 

In some cases. these services-intended for locating a company -s delivery drivers, constmction site supervisors, and 

the like-permit not only real-time monitoring but also review of historical PLI. 

17 Prior to the l006 addition of tracking device provisions, prosecutors used Rule -+ 1 to obtain \varrants \vhen 

needed to authorize the use of such devices. This practice flowed directly from the Supreme Court' s directive in 

United States v. Kora. ~68 U.S. 705, 718 (1984). to seek a warrant for certain tracking device uses. Prior to the 1986 

enactment of the pen register statute. the Supreme Court likewise read Rule 41 as "sufficiently flexible" for use in 

3ulhori:.t.ing prospective surveillance of dialed lc1cphonc numbers. l/niwd S'tates v. ,,\iew York Telephone Co., .+3.+ 

U.S. 159, 169 (1977). And Ihc rederal circuils arc unanimous in rching on Rule 41 as aulhorily ror issunncc or 

surreptitious vidco survcillancc \varrants, cvcn though thc Ru1c contains no cxplicit provisions contcmplating this 

usc. S'ee, e.g, Uniied S'wtes v. Ko.vomejian, 970 F.2d 536, 5.+2 (9th Cir. 1992) (en hane); United SlaWS v. CuevasSanchez. 821 F.2d 248, 252 (5th Cir. 1987). 

18 See. e.g, Uniled Siaies v. Orlega-r.:,·lrada. 2()()X WL 4716949 al *14 (N.D. Ga. Ocl. 22,2(08). 

1Y See. e.g, Criminal Complaint. liniledSlalesv. Capilo (D. Ari/" Mar. 12,2(10) (dcseribing. al pp. 12-15.lhc usc 

or lowcr dump dala 10 idcnliry Ihc phones used by suspccls al rour scparalc anned bank robberics), available al 

llliJ1.L/Jj!l\lu.J&Q.lU/lO\\ crQ.L!J"tlll· 

- 8-
17 

requested time frame, and the type of area (rural, suburban, or urban) at issue, but can 

reveal thousands or even tens of thousands of records 2o 

Given the potential for disclosure of such customer information, the Committee may wish 

to consider the desirability of additional statutory protections such as limits on the 

number of records or the length of the time window requested, or protocols for sealing or 

destroying voluminous non-pertinent records . 

. ). Warrants or orders to surveil unidentified phones contacting a target phone. Prosecutors 

at the state level sometimes apply for warrants or court orders that authorize monitoring 

the location not only of a named target phone (as to which they must establish probable 

cause), but also of any other phone that contacts (or is contacted by) the target phone 

during the authorized period of surveillance. This is a troubling practice: it allows for 

location monitoring of an undetermined number of phones not identified in the warrant, 

and on the questionable assumption that even a single contact with the target phone 

constitutes evidence of criminal activity 

In light of the potential for significant, unjustified privacy invasions-for example, from 

misdialed numbers or calls trom family members or others uninvolved in criminal 

activity-the Committee should carefully consider whether additional safeb'llards are 

required to limit or prohibit these types of orders. 

4. Legal framework for real-time PLI monitoring. More generally, the Committee may wish 

to examine the adequacy of the current, somewhat ad hoc use of Rule 41 to authorize 

real-time law enforcement access to PLI. Specitic areas for potential review include the 

following: 

a. Whether the "tracking device" provisions are adequatefor lise in this area. Rule 

41 requires that a "tracking device" warrant be issued in the district where the 

device is "install[edl,,21 Although this poses no problems in the case of the 

physical tracking devices clearly contemplated by the Rule's drafters, it is a 

potentially serious obstacle in situations where (I) the court believes the tracking 

device provisions strictly apply to cell phone location and (2) the applicant cannot 

attest that the phone is within the district at the time of application. Indeed, since 

the objective of such applications is to learn the location of the target phone 

through court-authorized electronic surveillance, this requirement generally 

creates a Catch-22. 

b. Burden on servia providers, and compensation there/in'. Rule 41 does not 

impose any explicit limit on how often law enforcement may request PLl in the 

course of executing a prospective warrant. In many instances, manual intervention 

by carner personnel is necessary, often on nights and weekends, making trequent 

,u According to the CapilO complaint. "liJnvestigators used the rour most rurallbank robbcrv J locations in order to 

minimi:l.c the amount or extraneous telephone data that \vQuld likely be obtained ... ," lei. at 13. 

'I Fed. R. Crilll. P. ,\1 (b)(.\). 

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18 

requests extremely burdensome. Moreover, Rule 41 contains no provisions for 

compensating carriers for their often substantial compliance costs. 

c. Emergency requests. Both the Wiretap Act and the pen register statute include 

express language allowing law enforcement to conduct surveillance in 

emergencies without tlrst obtaining court authorization. 22 Each of these statutes 

requires the government to apply to a court for retroactive authorization within 48 

hours. By contrast, Rule 41 contains no such emergency compulsion provision. 

IV. CONCLUSION 

ECPA and its companion statutes currently provide significant privacy protection for wireless 

customers' location data. However, at least one gap in the statute has provoked widespread 

disagreement among federal judges, and other practical and procedural difficulties have emerged 

over time. Because these problem areas have a direct impact on user privacy, on service 

providers' compliance practices, and on our Nation's law enforcement efforts, the Committee 

deserves great credit for recognizing the need to re-examine the existing legal authorities and 

consider potential solutions. 

Thank you for this opportunity to testify. I look forward to your questions. 

:: See 18 U.S.c. §§ 2518(7) (wiretnp emergency authority) & 3125 (pen register). 

- 10-
19 

Mr. SENSENBRENNER. Thank you. 

Mr. Modaferri? Could you please press the voice button? 

TESTIMONY OF PETER A. MODAFERRI, 

INTERNATIONAL ASSOCIATION OF CHIEFS OF POLICE 

Mr. MODAFERRI. Good morning, Chairman Sensenbrenner, Ranking Member Scott, and Members of the Subcommittee. 

Thank you for this opportunity to discuss the role that 

geolocation information plays as evidence in criminal investigations 

and its importance in law enforcement’s effort to seek justice and 

public safety in the 21st century. 

It is from the vantage point of being a detective for 40 years and 

currently chief of detectives and longtime chairman of the IACP’s 

Police Investigative Operations Committee that I have seen a great 

deal of—a great and growing value of geolocation information to 

criminal investigations. Two issues have arisen over the past 10 

years, which have increased this value significantly—globalization 

and wrongful convictions. 

When this information is obtained in early stages of investigation, it provides fundamental building blocks on which successful 

cases may rest. Requiring probable cause in the initial stage of investigation to obtain certain types of geolocation information would 

make it significantly more difficult to solve crimes. 

Investigative issues of time, technology, and process must be addressed in a way that allows us to proceed from the initial stages 

of an investigation, where little is known and nothing can be assumed, to a point where investigators establish probable cause. 

The classic questions presented in investigations—who, what, 

where, when, why, and how—can be answered with geolocation evidence. To learn facts and make valid assumptions, investigators 

use available geolocation evidence as a filter to help corroborate or 

refute statements and conclusions at any time during investigation, 

to confirm or dismiss alibi statements or claims of witnesses, and 

to act as—for stored times and places, it can be the only witness 

at a crime scene. 

Geolocation information gives us more than the ability to solve 

crime. It can prevent wrongful arrest by revealing the suspect was 

not at the scene of the crime. Mistaken identifications are a leading 

cause of wrongful convictions. 

It can provide us with accurate time and place evidence that can 

confirm or refute identifications, confessions, and inaccurate testimony. Justice and public safety in the 21st century is a new 

ballgame. Today’s criminal investigators are more mobile than 

ever. That makes law enforcement access to geolocation information all the more important. 

Law enforcement must take advantage of geolocation information 

and location-based information just as the private sector does. 

Smartphones, mobile devices, GPS, and preinstalled technology like 

OnStar are available with more location technology evolving at a 

rapid pace. 

Technologies generate—also generate historical data and business records from which location information can be derived. EZPass, credit card, and debit transactions are examples. 
20 

If we do not have standards of access in place to ensure we can 

get location evidence early in a case, then law enforcement will 

miss out on the productivity impact of advancing technology. That 

affects our ability to do our jobs the best we possibly can. 

An example that demonstrates this type of importance of 

geolocation information was a bank robbery case in the Rockland 

County area. In the area around Rockland County, there were 

seven bank robberies. We had no success in identifying the perpetrators of those crimes until a witness came forward. She was a 

victim of one of the crimes, and she was at a gas station and saw 

a person who she believed was one of the robbers. And she was 

able to take a photograph of that person’s car, and it had dealer 

license plates on it. 

Using a subpoena, the detectives were able to get a possible identity on the person who purchased that car. Police then focused on 

the—with the subpoena on the basis of subscriber information and 

phone numbers. That was followed by a so-ordered subpoena, 

which produced historical cell site locations. Then a trap and trace 

pen register surveillance with location authorization was established. 

Utilizing probable cause, we then attached a GPS device. The result was an arrest of the suspects immediately after their next robbery, while they were holding the proceeds of the crime. 

At the beginning of the case, standard identification procedures 

were of little value, and there were no suspects in the case. A witness opened a criminal investigation. To build the case, subpoenas 

for stored cell phone call detailed records with location information 

were issued once we had that lead. 

The subpoenas produced suspects and locations that were essential to reach probable cause. Throughout the investigation, location 

information revealed and confirmed the activities of the true perpetrators. Not only did it help identify the right people, it resolved 

a misidentification and prevented a wrongful arrest. 

To conclude, Mr. Chairman, geolocation information has become 

an essential building material in the construction of many criminal 

investigations. It could be the concrete that cements eyewitness 

identification, the criminal, and the crime scene together. 

To gather and integrate this information in the initial stages of 

an investigation, we must have reasonable balance between the 

standards of access required to obtain location evidence and the 

need of the investigation to proceed. Just as important, law enforcement must be able to receive these facts in a rapid and complete response from the holder of the information record. 

Requiring probable cause to get basic limited information about 

a person’s historical location could make it significantly more difficult for us in law enforcement to solve crimes and seek justice. 

Thank you. 

[The prepared statement of Mr. Modaferri follows:] 
21 

Statement of Peter A. Modafferi 

Before the 

Committee on the Judiciary 

Subcommittee on Crime, Terrorism, Homeland Security and 

Investigations 

United States House of Representatives 

2141 Rayburn House Office Building 

Washington, D.C. 20515 

HEARINGON THE ELECTRONIC COMMlJNICATIONS PRIVACY ACT 

(ECPA) PART 2: GEOLOCATION PRIVACY AND SURVEILLANCE 

Peter A. Modafferi 

Chief of Detectives 

April 25, 2013 

Rockland County, N.Y. District Attorneys Office 

County Court House 

1 South Main Street 

New City, N.Y. 10956 
22 

Introduction 

Good Morning Chairman Sensenbrenner, Ranking Member Scott, and distinguished 

members of the subcommittee. Thank you for this opportunity to speak to you this 

morning to discuss geolocation information, the role that information plays as evidence in 

criminal investigations, and its importance in law enforcement's effort to seek justice and 

public safety in the 21'[ century. 

My name is Peter A. Modafferi and I am the Chief of Detectives of the Rockland County, 

New York District Attorney's Office. I also Chair the Police Investigative Operations 

Committee of the International Association of Chiefs of Police and I have worked on a 

number of boards, working groups and committees concerned with issues related to 

criminal investigations. 

I have been a detective for 41 years. For many years 1 conducted investigations into all 

types of criminal activity and I now lead, direct and coordinate these investigations. 

Today I wish to share with you what I have learned about investigations both from my 

experiences in Rockland County and from the exposure to the iield which I have gained 

through various committees and working groups. 

It is from this vantage point that 1 have seen the great potential that lies in law 

enforcement's utilization of the innovations in geolocation information Utilizing this 

information in the early stages of an investigation often provides fundamental building 

blocks on which cases may rest. Requiring probable cause in the initial stage of an 

investigation to gain access to geolocation information would make it significantly more 

difficult to solve crimes. 

It is my observation that, today, there is a digital evidence aspect to nearly every crime 

scene. Increasingly, those scenes are filled with digital evidence and, inevitably, to fully 

benefit from that evidence we must gather geolocation information. Some of this valuable 

evidence that is crucial in generating leads and ruling out suspects is in jeopardy if we are 

held to a probable cause standard to access every aspect of geolocation data. 

There are issues of time, technology and process that must be addressed in such a manner 

that will allow us to proceed with an investigation from its initial stages, where little is 

known and nothing can be assumed, to a point where we go in the direction of 

establishing probable cause. From this point, we will hopefully proceed to an arrest that 

will withstand the rigors of due process and the judicial system and lead with 100% 

accuracy to a conviction beyond a reasonable doubt. 

My Perspective 

Crime is and always will be one of the most serious issues confronted by civilization. 

2 
23 

Today's communications systems, worldwide information services, massive participation 

in social media services and multi-national economic partnerships have dramatically 

impacted our society. It is to this "globalized" environment that law enforcement must 

adapt, culturally and technologically in order to address crime. 

The Investigative Process 

Why is geolocation information valuable to law enforcement? 

In the initial stages of an investigation, law enforcement seeks to quickly develop leads 

and theories that incorporate answers to classic questions presented: Who, What, Where, 

When, Why and How. Geolocation evidence can inform the answer to each question. 

The unique value of geolocation information is found in its two components - an accurate 

location and an accurate time the location was determined. 

When investigators start working a case, little may be known and nothing should be 

assumed. To know pertinent facts and make valid assumptions, investigators use 

available geolocation evidence as a filter. This process allows investigators to winnow 

out and prioritize leads from the unorganized mass of related and unrelated information 

that surrounds a crime and a crime scene. 

This process is the beginning of the effort to assemble an offering of probable cause to 

believe that a certain person or persons committed the crime, and that particular evidence 

will be found in specific locations. 

Through the lens of geolocation evidence, investigators press to correctly determine an 

answer to Who, When and Where - what witnesses, victims, knowledgeable persons and 

perpetrators - were in the vicinity of the crime at about the time it occurred. 

How is geolocation evidence used in an investigation? 

In addition to providing clarity by answering some or all of the initial questions 

presented, the time and place components of geolocation information can be of use to 

corroborate or refute statements and conclusions offered at any time during the 

investigation. 

Geolocation information can be used to confirm or dismiss alibi statements that are 

offered to show that a subject was not present at the time and place the crime occurred, or 

to confirm or dismiss the claim of a witness or another knowledgeable person who was 

present at a certain time or place. 

A location-enabled digital device can be a "witness" to a crime. In fact, in cases where a 

human witness does not exist or is not discovered, the stored contents of the device may 

3 
24 

be the only initial "witness" available to investigators. In this case, the geolocation 

information components of time and place are of upmost importance. 

Justice and Public Safety in the 21'( Century 

Evidence is the basic foundation for addressing crime and criminals. The investigative 

process is how we secure the evidence we need to protect society and attain justice and 

public safety in the 21 ,[ century. Today we are part of a digital world and in that world 

digital evidence abounds. 

Geolocation evidence is essential to obtain in the early stages of investigations when 

probable cause has not been established. Requiring probable cause to get basic, limited 

information about a person's historical location would make it significantly more ditlicult 

to solve crimes and seek justice for victims. 

We do not have the luxury of setting the pace at a crime scene or in conducting an 

investigation Ifwe are constrained by a process that slows our progress in pursuing 

justice by extending the timeline of an investigation, the digital evidence at a crime scene 

may well go unexplored, evidence not be seized and analyzed, and our investigation will 

not meet our needs or the expectations of victims or civilized society as a whole. 

The court room and judicial process are the safety net for a free and just society. That 

wrongful convictions have occurred is tragic and everything must be done to avoid them 

in the future. The process starts at the crime scene or with knowledge that a crime may 

have been committed and proceeds ahead. In the end, the basic fact is that you cannot 

have a wrongful conviction without a wrongful arrest. A wrongful arrest is the result of 

an inadequate investigation. 

We have found that wrongful arrests occur because what we thought was proof wasn't 

always concrete, and what we thought was science was not always definitive. Some of 

our investigations, based on flawed conclusions, were neither necessarily accurate nor 

conclusive. 

Geolocation information offers tremendous factual data that can be used to remedy these 

failures. Geolocation information can coniirm or refute identiiications, confessions and 

inaccurate testimony. 

Added to the issues raised through the examination of wrongful convictions is 

globalization. The "usual suspects" are not just from the "old neighborhood" anymore. 

Globalization has, in the words of Thomas Friedman "unleashed the energies of hundreds 

of millions of people" 1. Unfortunately some of those people and their energies result in 

1 The World is Flat, Thomas Friedman. Farrar. Straus & Giroux, April 2005 

4 
25 

crime. Criminal activity and the location of criminals is not restricted by the limits and 

boundaries of an earlier era. Many of those boundaries have evaporated. The only 

boundaries that now limit globalization are governmental, which for criminals are easy 

obstacles to overcome. 

To learn from this and better ourselves we must take full advantage of all that is available 

in today' s world. Processes, guidelines and standards must be developed that will allow 

law enforcement to gain from technological evolution and attain what Friedman refers to 

as "productivity impact." Utilizing all that can be found at a crime scene or directly from 

a device recovered through a crime scene will not simply result in an increase in arrests 

but also an increase in accuracy and effectiveness, which will lead to justice and public 

safety in the 21 ,[ century. 

An investigation is a process. It starts with the basics of who, what, when and where 

which may lead to a suspect, facts, evidence and probable cause to believe a suspect 

committed the crime. Utilizing geolocation information will offer substantial facts which 

will assist in obtaining a conviction beyond a reasonable doubt. 

Law enforcement in the 21 ,[ century must combine new technologies with new ways of 

doing business to maximize investigative potential, create productivity "breakthroughs" 

and bring criminals to justice. "Productivity impact" in law enforcement investigations 

can be achieved in part through effective use of geolocation information. 

A recent investigation into a series of bank robberies in the tri state area around New 

York City offers a significant example of how geolocation information can help solve a 

case and avoid a possible wrongful conviction. 

Two brothers, residents of New York City, had robbed seven banks in the suburbs outside 

of the city. Utilizing standard investigative methods, detectives developed a suspect. 

Bank employees however were not able to identify the individual because he wore a 

mask. As the investigation progressed, a teller from one of the banks that were robbed 

believed she had seen the defendant at a gas station and photographed the vehicle he was 

driving. However, none of the employees at the banks could identify the individual from 

the gas station as the robber. 

Utilizing a range of legal process from a subpoena to a court order, detectives obtained 

basic geolocation information, which eventually led to development of probable cause 

and the placing of a GPS system on the vehicle. Once probable cause was established the 

suspect's location was monitored by tracking his cell phone. 

The geolocation information obtained without a warrant at the beginning of the 

investigation when probable cause was not determined led to the arrest of two individuals 

immediately after a bank robbery. At the time of arrest they had the proceeds of the 

robbery in their possession. 

5 
26 

As it turned out the original suspect was not the individual who entered the banks during 

the robberies. He was a cousin. If not for the teller seeing one of the brothers and 

photographing the vehicle he has just purchased (it had dealer license plates at that time) 

the actual robbers would not have been traced. Though similar in appearance, the man at 

the gas station was the person who entered the bank not the person the police were 

focusing on. 

The right persons were arrested due to the effective use of geoloaction information at the 

early stages of the investigation when probable cause was not evident. Standard 

i denti fi cati on procedures were of no val ue. 

Following The Digital Footprint 

The essentials to ensure the effectiveness oflaw enforcement lie in establishing a basic 

foundation from which we can pursue investigations. Investigations don't start with 

probable cause; they lead us to probable cause. Through investigations we discover facts. 

From these facts we start to build our case, which will hopefully lead to building probable 

cause and a fact-filled evidentiary case that leads to guilt beyond a reasonable doubt. 

What is a "digital footprint" and how can investigators benefit from it? The science and 

technology behind geolocation has opened a new world filled with data that can 

corroborate or refute human observations. Geolocation information is part of a person's 

"digital footprint." 

Evidence garnered through geolocation information can be established through of all 

types of equipment and records. Phones, mobile devices, trackers, and preinstalled 

(On Star) technology are available today with more specific technology evolving at a 

rapid pace. Also from this technology comes the historical data and business records from 

which location information can be derived - EZ Pass, Credit Card / Debit Transactions, 

etc. 

To establish probable cause we need a reasonable, manageable balance between legal 

process and investigative responsiveness. 

As an example, an anonymous tip was offered to the Rockland County Drug Task Force. 

The tip included the name of an individual and a phone number connected to that 

individual. The caller stated that this person was operating a clandestine laboratory 

manufacturing illegal drugs. 

The person offering the information stated that the principals involved in this criminal 

conspiracy had met recently at the location of the laboratory The caller also stated an 

approximate date and time of that meeting. As is often the case, the initial information 

available to the investigators could not be confirmed and the person offering the 

information wished to remain anonymous. 

6 
27 

The first step in the investigation was to subpoena basic subscriber information and 

limited call detail records. These subpoenas were issued in an effort to further identify the 

user of the given phone number and to display incoming and outgoing calls to and from 

associate numbers. This was done in an attempt to propose that certain associate phone 

numbers pointed to other members of the group and to discern a communications pattern 

between the conspirators. Any other associate numbers were ignored. 

The boundaries of the infonnation sought were confined to the proposed date/time 

window suggested by the caller. 

Once a group of apparently related associate phone calls was established at the date and 

time proposed, historical geolocation information associated with the interacting phone 

numbers was obtained. This stored historical geolocation information is created and 

retained by the service provider during the operation of the cellular phone system. The 

boundary of this information was limited to the narrowed date/time in hopes that it might 

suggest a possible location of the meeting and the laboratory. 

The use of this geolocation information led to the possible location of the lab and this 

information combined with standard police surveillance procedures led to a search 

warrant for the lab based on probable cause. We would not have been able to establish 

probable cause without the geolocation information provided in response to the initial 

subpoenas. 

The technologies and records that can lead to geolocation of a criminal or exoneration of 

an innocent party varies between situations where geolocation is already "turned on" and 

recorded, and geolocation that results form a real time effort to obtain geolocation 

information. We can subpoena previously obtained records data or, following proper 

legal process, we can "turn on" appropriate technology. 

Conclusion 

Very little, if any, construction begins with out a foundation. Geolocation information is 

an essential building block in "the construction" of a criminal investigation. Often it will 

prove to be the concrete that cements eyewitness identification and the crime scene 

together. Geolocation puts us in an area where evidence and possibly a criminal or 

fugitive can be found. 

To gather up and cement these building blocks together in the initial stages of an 

investigation we must determine a reasonable, manageable balance between legal process 

and investigative responsiveness. (Note, an emergency situation initiates a different, 

more expeditious process). In a criminal investigation, or a public safety/security event, 

access to geolocational information and records is an essential requirement to the 

detennination of true facts. Likewise, it is essential to receive these facts in a rapid and 

complete response from the holder of that information or record. 

7 
28 

I have not attempted to address the science and techniques used to derive geolocation 

information because I am not a technologist. What I have addressed in my testimony are 

the needs, the logistics and the processes that relate to the use of technology that helps 

law enforcement make accurate, effective and efficient decisions in the course of an 

investigation. Requiring probable cause to get basic, limited infonnation about a person's 

historical location would make it significantly more difficult to solve crimes and seek 

justice. 

Thank you for your time and the opportunity to address this issue. 

8 
29 

Mr. SENSENBRENNER. Thank you. 

Ms. Crump? 

TESTIMONY OF CATHERINE CRUMP, STAFF ATTORNEY, 

AMERICAN CIVIL LIBERTIES UNION (ACLU) 

Ms. CRUMP. Good morning, Chairman Sensenbrenner, Ranking 

Member Scott, Chairman Emeritus, and Members of the Subcommittee. 

Thank you for the opportunity to testify on behalf of the American Civil Liberties Union. 

Over the past week and a half, our Nation has been gripped by 

the horrific events in Boston. Today, our thoughts remain with the 

victims of that tragedy and with their families. 

Although details of the investigation are still unfolding, it is apparent that electronic surveillance played an important role in locating and tracking the suspected perpetrators. That is as it should 

be. No one denies that electronic surveillance can be an important 

tool for law enforcement and, indeed, in horrific and rare events, 

such as what transpired in Boston, an essential one. 

That is why the ACLU has always supported an exemption in 

the law permitting immediate disclosure of location data in aid to 

agencies in such life and death situations. However, in routine investigations, law enforcement agencies, such as the local police and 

the FBI, should secure a warrant based upon probable cause to obtain mobile phone location data. 

The ACLU supports the Geolocation Privacy and Surveillance 

Act because the framework it establishes allows law enforcement 

agents to access the tools they need while providing an independent check and balance through review by a judge, which will 

ensure that innocent Americans do not have their privacy violated. 

Mobile phone location technology provides law enforcement 

agents with an invasive, yet inexpensive method of tracking individuals over extended periods of time and unlimited expanses of 

space, as they traverse both public and private areas. It also makes 

it possible for law enforcement agents to identify all individuals located in a particular location, a valuable tool, but one that, by necessity, can reveal the location of thousands or even tens of thousands of innocent Americans. 

In many parts of the country, the police have been tracking mobile phones for days, weeks, or even months at a time without ever 

having to demonstrate to an independent judge that they have a 

good reason to believe the tracking will turn up evidence of wrongdoing. 

Mobile phone location data implicates strong privacy interest because tracking people’s movements makes it possible to learn a 

great deal of personal and private information about them. As Justice Alito explained, society’s expectation has been that law enforcement agents would not and, indeed, in the main could not track 

people’s movements over a long period of time in their car, an observation which applies with even greater force to the cell phones 

people carry with them all the time. 

The warrant and probable cause requirements are essential components of the Fourth Amendment. The probable cause require-
30 

ment is not high. Law enforcement merely has to have a good reason to believe that a search will turn up evidence of wrongdoing. 

It is useful to identify points of agreement between law enforcement interests and those civil society organizations concerned 

about privacy. First, the Department of Justice already recommends that its agents obtain a warrant based upon probable 

cause to secure real-time precision location information, the very 

standard that the ACLU supports. 

Also, local law enforcement agencies, such as the County of Hawaii, Wichita, and Lexington, Kentucky, already secure warrants 

across the board. Thus, merely codifying a longstanding Department of Justice policy would help protect Americans’ privacy. 

Second, we agree with Mr. Eckenwiler, as he stated in his written testimony, that the so-called cell tower dumps, the acquisition 

of location data of all individuals at a particular location, pose especially grave privacy concerns because they could sweep up the locations of thousands of innocent Americans. Like Mr. Eckenwiler, 

we believe the Committee should consider additional statutory protection, such as limits on the number of records or the length of 

time window requested or protocols for sealing or destroying the 

documents obtained. 

We also agree with numerous law enforcement representatives 

that the current legal standards in force are unclear. However, we 

part ways over the applicable legal standard because the warrant 

and probable cause requirement should apply across the board to 

cell phone location data. 

These requirements are especially important today, given the tremendous and rapid technological development over the past 10 

years that make it easier than ever to track Americans’ every 

movement. The ACLU supports passage of the GPS Act because it 

would ensure that law enforcement agents obtain a warrant based 

upon probable cause to access mobile phone location data subject 

to appropriate exceptions. 

Thank you. 

[The prepared statement of Ms. Crump follows:] 
31 

ACLU 

AMERICAN CIVil LIBERTIES UNION 

Stateme nt of Cat he rille Cmmp, Staff Attorney 

American Civil Liberties Un ion 

On 

The Electronic Communications Privacy Act (ECPA), Pari 2: Geolocation 

Privacy and Surveillance 

Befor!! the House Ju diciary Subcommittee on Crime. Terrorism. and 

Homeland Securi ty 

Apri l 25, 20 13 
32 

Good morning Chairman Sensenbrenner. Ranking Member Scott and Members of 

lhe Subeommillee. Thank you for the 0pp0rLuniLy lo le,lify on behalf of the Ameliean 

Civil Liberties Union, its more than half a million members. countless additional activists 

and supporters. and fifty-three affiliate organizations nationwide. 

Over the past week and a half. our nation has been gripped by the horrific events 

in Boston. Today our thought, remain with the victims of this tragedy. with their families 

and with the diverse spectators and athletes that compri,e the iloston Marathon 

community. Although details of the investigation are still unfolding. it is apparent that 

electronic surveillance played an imponant role in locating and tracking the suspected 

perpelraLors. This is as il should be. No one dcnies lhaL cleclronie surveillance such as 

access lo mobile phone loealion data is a valuable law enforeemenl lool-and indeed, in 

horrific and rare events such as the Boston Marathon bombings. an essential one. That is 

why the ACLU has ,up ported and continues to support an exemption in the law, 

permitting the immediate disclosure of location data to law enforcement agencies in such 

life and death situations. 

However. in routine invesligaLions, law enroreement agencies such as local police 

and the FBI should secure a wammt based upon probable cause to obtain mobile phone 

location data. The ACLU supports the Geolocation Privacy and Surveillance Act becau,e 

the framework it establishes allows law enforcement to access the tools they need, while 

providing an independent check and balance through a review by a judge which will 

emure that innocent Americans do not have their privacy violated. 

I. Introduction 

Mobile phone technology provides law enforcement agents with an invasivc yet 

inexpensive method of tracking individuals over extended periods of time and unlimited 

expanses of space as they traverse public and private areas. It also makes it possible for 

law enrorecmenl agcnLs to idenlify all individuals located in a specific area-a valuable 

tool, but one that by necessity reveals the location of vast numbers of innocent 

Americans. In many parts of the country. the police have been obtaining mobile phone 

loealion dala ror days, weeks, or monlhs aL a Lime, wilhout ever having to demonslrate lo 

an independent judge that they have a good reason to believe that tracking will tum up 

evidence of wrongdoing. 

Congress should reform our electronic plivacy laws to require law enforcement 

agents to secure a wanant based upon probable cause to obtain mobile phone location 

daLa. The walTanL and probable cause requirements ensure lhaL an objeeLivc magislrale 

determines that there is a good reason to believe that a search will tum up evidence of 

wrongdoing before mobile phone location data is disclosed. The application of this 

sLandard as a rouline matter, coupled wilh immediale disclosure of location dala to law 

enforcement agencies in tme emergencies. would ensure that legitimate law enforcement 

investigations can proceed and that Americans will not suffer undue invasions of their 

privacy. 
33 

II. Mobile Phone Technology Enables Invasive Tracking of Americans' 

Movements. 

Today mobile phone technology makes it possible to obtain location data about 

the vast majority of Americans with greaL precision, in both real time and historically. As 

of June 2012. there were 321.7 million wireless subscriber accounts in the United 

States-a number greater than the total U,S, population,] Mobile phone technology has 

given law enforcement an unprecedented new surveillance tool. With assistance from 

mobile phone carriers. the govemment now has the technical capability to eove111y track 

anyone of the nation's hundreds of millions of mobile phone owners. for 24 hours a day, 

Cor as long as it likes. Through so-called "tower dumps," it can also identiCy all oC the 

individuals whose mobile phones used a particular tower-allowing law enforcement 

agents to infer who was present at a location days, weeks or months after the fact. 

A. Types of mobile phone location data available to law enforcement agents 

Mobile phones yield several types oC inCormation about their w,ers' pasL and 

present locations ami movements: cell site location data, triangulation data, ami Olobal 

Positioning System data, The most basic type of mobile phone location infolmation is 

"cell site" data or "cell site location information," which refer to the identity of the cell 

tower from which the phone is connected and the sector of the tower facing the phone. 

This uata is generated because whenever indiviuuals have their mobile phones on, the 

phones automatically and frequently scan for nearby cell towers that provide the best 

recepLion. The carriers keep track of the regisLraLion information to identify the cell towcr 

through which calls can be made and received, The towers also monitor the strength of 

the telephone's signal during the progress of the call to manage the hand-off of calls from 

onc adjacent tower to anothcr if the caller is moving dming the cal1.2 

The precision of cell site location information depends, in part, on the size of the 

coverage area oC each ccll tower. This means Lhat as the number oC cell towers installed in 

cities and towns has increased and the coverage area for each cell tower has shrunk, cell 

site location information has become more precise, As Professor Matt Blaze has testified, 

the latest generation of cellular towers now may cover an area as small as a Lunnel, a 

subway. a specific roadway. a particular floor of a building, or even an indiviuual home 

or office,] Customers with poor cell phone coverage in their homes can request that their 

1 CTlA, Wireless Quick Facts, 

http://www,ctia,org/advocacy/research/index,cfm/aid/l0323, 

2 See Decl. of Henry Hodor at 7 n.6, available at 

http://www.ac1u . org/pufs/freespeech/cellfoi,U'elease _ 4805_00 L20091 022. pdf. 

] Hearing on Electronic Communications Privacy Act Reform and the Revolution in 

!.ocation Bllsed Technologies lind SenJices Before the Subcomm. on the Constitution, 

Civil Rights, and Civil Uberties ot'the H. Comm. on Judiciarv, 111 Lh Congo 5 (20 I 0) 

(statement of Professor Matt Blaze), available at 

http://judiciary.house.gov/hearings/pdf/illazel()0624.pdf; Thomas rarely & Ken 

2 
34 

carrier provide them a "femtocelL" a small cellular base station. which can cover jmt one 

home. 4 As consumen, embrace data-hungry devices such as "marlphones. the caniers 

have installed more towers. each with smaller coverage areas in order to cope with the 

demand for data. 

Further improvement in precision can be expected given the explosive demand for 

wireless technology and its new services. to the point that "[tlhe gap between the 

locational precision in today'" cellular call detail record" and that of a UPS tracker is 

closing, especially as carriers incorporate the latest technologies into their networks.·,5 In 

the words of Professor Blaze. "[ilt is no longer valid to assume that the cell sector 

recorded by the nelwork will give only an approximale indicaLion of a user's localion.,,6 

In addition to cell site information. law enforcement agents can obtain location 

data at a high level of accuracy by requesting mobile phone carriers to engage in 

"triangulation." which entails collecting and analyzing data of the precise time and angle 

at which the mobile phone's signal arrives at multiple cell towers. CUtTent technology can 

pinpoinL lhe location of a mobile phone LO an accuracy of wilhin 50 melers or less 

anylime lhe phone is on, and the accuracy will improve wiLh newer lechnology.7 

Pinally, a mobile phone that has UPS receiver hardware built into it can determine 

its precise location by receiving signals from global positioning satellites. Current UPS 

technology can pinpoint location when it is outdoors. typically achieving accuracy of 

within 10 meters.s 

B. Types of government requests for mobile phone data 

Law enforcement agents can request two categories of cell site location 

information: historical cell site data, which can be used to retrace previous movements. or 

prospective cell site data, which can be used to track mobile phones in real time. The 

availability of hislorical informalion and the IengLh of time lhis information is sLored 

depend on the policies of the mobile phone carrier. According to an internal Dep31tment 

of Justice document, obtained by the ACLU through a public records act request. mobile 

phone carriers SLore lheir cusLomers' historical locaLion informalion for significanl 

periods of time: Verizon stores the cell towers used by a mobile phone for "one rolling 

year"; T-Mobile keeps this information "officially 4-6 months. really a year or more"; 

Schmidt, Cellular Telephone Basics: Basic Theory and Operation, Private Line (Jan. 1, 

2006). http://www.privateline.com/mccellbasics/iv _basic_theory _and_operation!. 

4 Stephanie K. Pell & Christopher Soghoian, Can You See Me Now? Toward Reasonahle 

Standards for Law Enforcement Access to Location Data That Congress Could Enact. 27 

Berkeley Tech. LJ. 117. 132 (2012). 

5 SlaLemenl of Professor Mall nJa/'e, supra noLe 3, al 13-14. 

6 1d. aL 13. 

7 1d. at 10. 

SId. at 5. 

3 
35 

Sprint and Nextel store this data for "18-24 months"; and AT&T/Cingular retains it 

'"from July 2008.,,9 

Law enforcement agencies can obtain data regarding the movements of one or 

more persons over time, or Lhey can obLain data regarding all or the people whose phones 

were using a particular tower at a particular time. This latter method of obtaining cell site 

location information is often referred to as a "tower dump," Because tower dumps obtain 

the information of everyone whose phone was using a particular cell phone tower, by 

their nature they sweep in vast quantities of data about innocent people who will never 

know that their location data was shared with the govenunent. 

Mobile carriers have established automated systems to provide location and other 

customer data to law enforcement agents, For example, Sprint created a website, which 

was used to transmit 8 million "pings" of location data in a year.1O S print charges $30 a 

month per target for use of its L-Site program to track location. 11 Location surveillance is 

one of the cheapest and easiest, yet most invasive fonns of govemment surveillance. 

lIl. Current Law is Unclear and Inadequately Protective of Privacy. 

There is eonrusion among courts, law enroreement agents and members or the 

public regarding what legal standard law enforcement agents must meet to obtain mobile 

phone location data, The principal law that govems law enforcement access to records 

regarding electronic communications, the Electronic Communications Privacy Act of 

1986. does not expressly address law enforcement access to mobile phone location data. 

In fact, one federal appellate court stmggling to apply the law to a govemment request for 

hisLOrieal cell siLe location informaLion stated Lhat iL was '"stymied by the failure of 

Congrcss to make its intcntion clear.,,12 

The ACLU has doeumemed the resulLing patchwork of varied and conllicLing 

legal standards, In August 2011, 35 ACLU affiliates submitted public records requests 

with state and local law enforcement agencies around the nation seeking information 

about their policies. procedures, and practices for obtaining mobile phone location data. 13 

9 U,S, Dep't of Justice, Retention Periods of Major Cellular Service Providers (Aug, 

20 I 0), available at https:llwww.aclu.org/cell-phone-Iocation-tracking-request-responsecell-phone-company-data-retention-chal1, 

10 Pell & Soghoian, supra note 4, at 121. 

11 Hclen A.S. Popkin. Carriers Charge Cops for Cellphone Injt)rmation, NIlCNews.com, 

http://www.nbcnews.com/technology/technolog/caniers-charge-cops-cellphoneinformation-656559, 

12 In re Application of' U.S . .tt)r an Order Directing a Provider of' Flee. Commc'n Servo to 

Disclose Records to Gov't. 620 F.3d 304, 319 (3d eiL 2010). 

13 Supporting documentation demonstrating the factual assertions throughout this section 

can be found at ACLU, Cell Phone Location Tracking Public Records Request (Mar. 25, 

2013), http://www.aclu .org/protecting -civil-libel1ies-digital-a ge/cell-phone-locationtracking-public-records-request, 

4 
36 

Over 200 local law enforcement agencies responded. While the overwhelming majority 

engaged in alleasl some cell phone lracking, the legal standards lhey mel varied widcly. 

For example, police in Lincoln. Nebraska obtain even GPS data without a warrant based 

upon probable cause. Police in Wilson County, North Carolina obtain historical cell site 

location information by prolTering only lhat the data is "'relevant and malerial" lo an 

ongoing investigation. Yet some police departments, including police in the County of 

Hawaii. Wichita. and Lexington. Kentucky, do secure warrants based upon probable 

cause to obtain mobile phone location data. If these police departments can protect both 

public safety and plivacy by meeting the warrant and probable cause requirements, then 

surely other agencies can as well. 

Moreover. it is not just state and local law enforcement agencies that obtain 

mobile phone location daLa under inconsistcnl standards. The U.S. Altomcy's Officcs 

appcar lo do so as well. The Deparlmenl of Justice rccommends Lhat law cnforccmenl 

agents obtain a warrant based upon probable cause to precise access real-time location 

data. 14 However. not all U.S. Attorneys Offices comply with this recommendation. 

Litigation by the ACLU and Electronic Frontier Foundation revealed that U.S. Attomey's 

Offices in the District of New Jersey and the Southern District of Florida have obtained 

even what the Department of Justice classifies as precise mobile phone location data 

wilhoUL oblaining a warranL and showing probable cause. 15 

Unfortunately. today the federal government's policies. procedures and practices 

for obtaining mobile phone location data are more opaque than ever. In what has been 

labeled as the most consequential Fourth Amendment decision in a decade. in United 

States v. Jones, the Supreme Court held that attaching a GPS device to a car and tracking 

ils movemcnts is a scarch undcr the PourLh Amendmcnl16 Jones. howcvcr. IcfL 

unrcsolved whcther such GPS tracking is thc sort of scarch that rcquircs a WalTant based 

on probable cause. Moreover. the Court did not discuss how its holding would apply to 

surveillance performed with other technologies such as mobile phone tracking. While 

FBI General Counsel Andrew Weissmann has explained that the Department of Justice 

has issued two guidance memoranda setting out its view of how Jones affects the 

constitutionalily of various forms of localion lracking, nciLhcr has becn made public 

despite an ACLU requesl for lhem under the Freedom of InformaLion Acl. The ACLLJ 

has filed suit in federal court to force the release of these memoranda. 

14 The Electronic Communications Privacy Art: Government Perspective on Protecting 

Privacy in the Digital Age: Hearing Before the S. Comm. on Judiciary, 125th Congo 7 

(2011) (statement of James A. Baker, Associate Deputy An'y Gen., U.S. Dep't of 

Justice). available at http://l.usa.gov/IsojNy. 

)5 ACT >U. ACUJ v. Department of Justice: ACUJ rawsuit To Uncover Records of Cell 

Phone Tracking (Sepl. 6. 2() II), hLLp:llwww.aclu.org/free-speech/aclu-v-deparlmenljustice 

16 132 S. Ct. 945, 949 (2012) 

5 
37 

IV. Tracking People's Location Can Invade Their Privacy Because It Reveals a 

Great Deal Ahout Them. 

Location tracking enables law enforcement to capture details of someone's 

movements ror mOnLhs on end, unconstrained by the normal barriers or cost and ollicer 

resources,17 In United States v. Jones,18 the Supreme Court held that a Fourth 

Amendment search occurred when the government placed a GPS tracking device on the 

defendant's car and monitored his whereabouts nonstop for 28 days.19 A majority of the 

Justices also stated that "the use of longer term GPS monitoring. . impinges on 

expectations of privacy" in the location data downloaded from that tracker. 20 As Justice 

Alito explaineu, "[s]ociety's expeeLation has been Lhatlaw enrorcemenL agents and others 

would not -- and indeed, in the main, simply could noL -- secreLly moniLor amI catalog 

every single movement of an inuividual's car, for a very long period.,,21 

Justice Sotomayor emphasized the intimate nature of the infOlmation that might 

be collected by the GPS surveillance, including "trips to the psychiatrist, the plastic 

surgeon, the abortion clinic, the AIDS LrcatmenL center, the sllip club, the criminal 

dcl'ense allomey, the bY-Lhe-hour motel. the union meeting, the mosque, synagogue or 

church, the gay bar and on and on.,,22 While even the limited collection of geolocation 

information can reveal intimate and uetailed facts about a person, the privacy invasion is 

multiplied many times over when law enforcement agents obtain geolocation information 

for prolonged peliods of time. As the D.C. Circuit Court of Appeals has observed, ''[a] 

person who knows all of another's travels can deuuce whether he is a weekly church 

goer, a heavy drinker, a regular aL the gym, an unraithl'ul hw,baml, an outpatient receiving 

medical treatment, an associate of pat1icular individuals or political groups-atld not just 

one such fact about a person, but all such faets."n 

There have always been facets of American life that have been uniquely 

safeguardeu from the intrusive interference and observation of government. Location 

tracking threatens LO make even Lhose aspects or lire an open book to govemmenl. As 

Justice Sotomayor pointed out in Jones, "Awareness that the Government may be 

watching chills associational and expressive freedoms. And the Government's 

17 See United States v. Pineda-Moreno, 617 r.3u 1120, 1124 (9th Cir. 2010) (Kozinski, .T, 

dissenting from denial of rehearing en banc) CThe modem uevices used in PinedaMoreno's case can record the Cat"s movements without human intervention---quietly, 

invisibly, with uncanny precision. A small law enrorcemenL team can deploy a dw.en, a 

hundred. a thousand such devices and keep track of their various movements by 

computer, with fat· less effort than was previously needed to follow a single vehicle."). 

18 132 S. Ct. 945, 954 (2012) 

19 !d. at 954. 

20 ld. at 953-64 (Sotomayor, J., concurring); see also id. at 964 (Alito, J., concurring). 

21 Td. aL 964 (AliLO, .T., concurring). 

221d. aL 955 (quoLing People v. Weaver, 12 N.Y.3d 433, 442 (N.Y. 20()9)). 

2.1 Uniled Slales v. Maynard, 615 F.3d 544, 562 (D.C. Cir. 2010), af1'd sub nom. United 

States v . .Tones, 132 S. Ct. 945 (2012). 

6 
38 

unrestrained power to assemble data that reveal private m,pects of identity is susceptible 

lo abusc.,,24 rurlhcr, location informaLion from ccll phoncs can rcvcal pcople's locations 

and movement within their h~~mes and other spaces that receive heightened protection 

under the FOUlth Amendment."' 

While privacy lights are often conceptualized as belonging to individuals, they are 

also important became they ensure a specifically calibrated balance between the power of 

individuals on the one hand and the state on the other. When the sphere of life in which 

individuals enjoy privacy shrinks. the state becomes all the more powerful: 

The nct rcsulL is Lhal GPS monitoring--by making available al a 

rclalivcly low cosl such a substanlial l[uanlum or inLimatc 

information about any person whom the Government, in its 

unfettered discretion, chooses to track--may alter the relationship 

between citizen and government in a way that is inimical to 

democratic society?" 

ChicI' .fudge Ko/,inski or the U.S. Courl or Appeals ror the Nimh Circuit has elaborated 

on this critical point: 

T don'l lhink lhat most people in the UniLed Stales would agree wilh Lhe 

panel that someone who leaves his car parked in his driveway outside the 

door of his home invites people to crawl under it and attach a device that 

will lrack the vehicle's every movement and lransmit lhat inrormalion to 

total strangers. There is something creepy and un-Amelican about such 

clandestine and underhanded behavior. To those of us who have lived 

under a lolaliLarian regime, there is an eerie fecling of deja VU.27 

Furthennore. while the govemment routinely argues that records of a person's 

prior movemenls deserve less privacy proLection than records or where a person travels in 

real time, this is a meaningless distinction. As one judge has noted, "ltjhe picture of la 

24 Jones. 132 S. Ct. at Y56 (Sotomayor. J., concurring) (quotations omitted). 

25 See In re Application oj the United States oj America Jar Historical Cell Site Data. 747 

r. Supp. 2d 827, 840 (S.D. Tcx. 2010) ("[Cell siLe loealion informalionl will also 

inevitably be more intrusive [than vehicle GPS trackingj. because the phone can be 

monitored indoors where the expectation of privacy is greatest."); see also In the Matter 

of the Appliclltion of the United States of America for an Order f)irecting a Provider of 

f.'lectronic Communication Service to Disclose Records to the Government, 620 F.3d 304. 

318 (3d Cir. 2010). 

26 Jones, 132 S. Ct. at Y56 (Sotomayor. J., concurring) (quotations omitted). 

27 United States v. Pineda-Moreno. 617 F.3d 1120. 1126 (Yth Cir. 2010) (Kozinski. C.J.. 

dissenting). See also United States v. Cuevas-Perez. 640 F.3d 272,286 (7th Cir. 2011) 

(Wood, J.. disseming) ('The lcchnologieal devices available ror [moniloring a person's 

movemenlsj have rapidly attained a degree or accuracy lhaL would have been 

unimaginable to an earlier generation. They make the system that George Orwell 

depicted in his famom novel, 1984, seem clumsy and easily avoidable by comparison."). 

7 
39 

person]'s life the government seeks to obtain is no less intimate simply because it has 

already been painled."z8 Il i, hard LO sec how daily requesL, for hi,loriealloeaLion differ 

from continuous real-time tracking. 

While the Jones case deall with long-Lelm lracking or movcmenls, evcn single 

points of mobile phone location data can intrude upon reasonable expectations of privacy 

- a single GPS data point revealing that someone is in the waiting room of an ahortion 

clinic, a church or at an AA meeting can reveal information that is highly semitive. The 

Supreme C0U11 has held that location tracking even using relatively clllde ""beeper" 

trackers implicates reasonable expectations of privacy where it '"reveals information that 

could not have bcen ohlained lhrough visual surveillance rrom a puhlic spacc.,,29 ror this 

reason, and hecausc law enrorccmenl agcnls olkn will nol know whether a parlicular 

piece of mobile phone location data will implicate a person's privacy interest in their 

location in private space" the better rule is an acro"-the-hoard requirement that law 

enforcement agents obtain a warrant based on probable cause for mobile phone location 

data. 

V. Congress Should Act to Protect Americans' Privacy by Imposing a Warrant 

and Probable Cause Requirement for Mobile Phone Location Data. 

Congress is in a good position to protect Americans' privacy. In his concunence in 

Jones, Justice Alito wrote: "'In circumstances involving dramatic technological change. 

the hest solution to privacy concern, may be legislative.,,30 Given that it will likely take 

years hcrore the Suprcme Courl oncc again considcrs the consLiLuLionalily or localion 

tracking. Congress should not stand by as the privacy of Americans is invaded due to 

confusion over the rules. 

The warrant and probable cause requirements play important roles in safeguarding 

Americans' privacy. The function of the warrant clame is to safeguard the rights of the 

innoccnt by prevenLing Lhc staLc rrom conducling scarches solely in iLS discreLion: 

Ahsent ,ome grave emergency, the Fourth Amendment has interposed a 

magisLralc helwcen the ciLi;:en and the police. This was done noL LO shicld 

climinals nor to make the home a safe haven for illegal activities. It was 

done so that an objective mind might weigh the need to invade that 

plivacy in order to cnrorce the law. The right or privacy was deemed LOO 

precious to entlllst to the discretion of those whose job is the detection of 

crime and the alTest of climinals. Power is a heady thing; and history 

shows Lhat the police aCling on lheir own cannol he trusled 31 

2R In re Application of the U.S. for Historical Cell Site Data. 747 F. Supp. 2d 827. 840 

(S.D.Tex. 201 0) (citalion omitled). 

29 United States v. Karo, 468 U.S. 705. 707 (llJ84). 

30 132 S. Ct. at 964. 

31 MrDonald v. United States, 335 U.S. 451, 455 (1948). 
40 

The warrant and probable cause requirements are especially important here given the 

eXLraordinary intrusiveness of modem-day eleclronic surveillance. 

The watTatlt requirement imposes no unreasonable burden on the law enforcement 

agents - Lhey obLain Lhese regularly and roulinely for searches of homes. vehicles and 

email accounts. Warrants are a elear and familiar standard. requested by law enforcement 

and issued by judges for hundreds of years. Moreover, under the GPS Act. obtaining 

warrants for geolocational information would be even less burdensome than the process 

law enforcement agencies have followed for decades to obtain telephone wiretaps. 

VI. Specific Issues 

While privacy advocates and law enforcement agents may disagree about many 

aspects of law enforcement access to mobile phone location data, it is helpful to start out 

by identifying points of common ground. The Department of Justice already 

recommends that its agents obtain a warrant based upon probable cause to engage in 

precise forms of real-Lime mobile Lracking32 This is idemieal lo the slandard advocated 

by the !\CLU and olhers pushing for reform, and it is the slandard Lhat would be 

mandated by the GPS Act. 

There is disagreement regarding what standard law enforcement should meet to 

engage in less precise forms of real-time tracking such as cell site location infonnation. 

but this is an increasingly illusory divide. As Professor Dlaze has explained, today cell 

site 10caLion informalion can be very precise and can place people inside consLiLuLionally 

protected spaces such as a home. Cell cite location information will only get more 

precise over time. Unless Congress wishes to revisit this issue every few years in order 

to evaluate the accuracy of eun'ent location tracking technology, the standard for all 

types of real-time location tracking should be the same. That is the only standard that 

will have any hope of standing the test of time. 

There is also disagreement regarding what the standard should be for historical 

location data. Because. as discussed above, people have just as strong a privacy interest 

in where lhey have been in the past as they do in where lhey will go in the fULure. law 

enforcement agents should also have to obtain a warrant based upon probable cause to 

access historical mobile phone location data. 

Another area of contention is how to handle law enforcement requests for "tower 

dump" data. These requests have unique features. in pa11icular the way in which they 

sweep in the locaLion daLa aboul vast numbers of innocenl individuals. Il is imporlanL 

that law enforcement agencies implement strict minimization and notice requirements so 

that after the investigation is over. the individuals are told that their data was obtained by 

32 See The Electronic Communications Privacy Act: Govemment Perspective on 

Protecting Privacy in the Digital Age: Hearing Before the S. Comm. on Judiciary, 125th 

Congo 7 (2011) (slatemenl of .Tames A. Baker, AssoeiaLe Depuly All'y Gen., U.S. Dep'L 

of Justice). Ilvailable at http://l.usa.gov/IsojNy. 
41 

law enforcement. Aho, law enforcement agencies should not indefinitely retain data on 

innocenL people. 

Finally, the ACLU believes that "emergency" must not become a catch-all phrase 

Lhat allows policc LO skirt appropriatc slanclards. While obviow,ly legitimale 

emergencies must be hancllecl quickly, in every case they shoulcl be followecl by an 

explanation filecl with the court that describes the circumstance of the emergency and 

certifies that the facts surrounding it are true to the best of the officers' knowledge. 

VII. The ACLU Endorses the CPS Act. 

The ACLU supporls passage or Lhc UPS ACL bccausc il would cm-ure thal law 

enforcement agents obtain a warrant for geolocation information. subject to certain 

reasonable exceptions. 

The hem1 of Act is the requirement that "[aJ govenunental entity may intercept 

gcolocalion inrormalion or require the disclosurc by a provicler or a covered service or 

gcolocalion inronnation only pursuanllo a walTanL issucd using the proccclures describecl 

in the Federal Rules of Criminal Procedure .... ".B In turn. Federal Rule of Ctiminal 

Procedure 41 provides that "a warrant may be issued for any of the following: (1) 

evidence of a ctime; (2) contraband. fruits of ctime. or other items illegally possessecl; (3) 

property designed for use. intencled for use. or used in committing a crime; or (4) a 

person to be arrested or a person who is unlawfully restrained." 

Thus. through its incorporation of the Rule 41 standard. the UPS Act strikes a 

reasonable-and constitutionally necessary-balance between privacy and law 

enforcement interests. Uncler this provision. for example. when law enforcemcnt agents 

have a good reason to believe that u'acking the location of a cell phone will tum up 

evidence of a crime. or that a cell phone was used during the commission of a crime. law 

enrorcement agenls will have little dilTicully persuading magisLraLe judges to granL them 

pelmission to engage in location traclang. 

Furlher, the UPS ACL conlains a limitecl number or exceplions. ror: 

Emergency access when "il is reasonable to believe lhat the life or safely of the 

person is threaLened"; 

Foreign intelligence surveillance coverecl by the Foreign Intelligence Surveillance 

Act of 1978; 

Law enforcement emergencies where there is not time to secure a warrant; 

To retrieve lost or stolen phones; 

To allow parents or guardians to monitor children; and 

When the user has consenLed. 

33 § 2602(h)(2). 

10 
42 

The GPS Act could be strengthened through the inclusion of reporting 

requiremeills regarding law enforeemeill agencies' eolleelion of geoloeaLion informalion. 

To be sure. law enforcement agencies may have a legitimate interest in keeping the 

details of specific investigations secret, but when it comes to aggregate statistical 

inCormation about the use oC speeiCie surveillance techniques. lhc public inlcrest is besL 

served through disclosure. 

Covert surveillance techniques are by their nature secret, which has important 

ramifications for the ability of both Congress and the public to engage in oversight. 

Robust reponing requirements playa valuable role in filling what would otherwise be a 

void oC inCormalion regarding the aclivilies oC government. Por example, each year the 

administrative ollice oC the eourls produces aggregale reports on the use oC wiretap 

authorities by law enforcement agencies nationwide. Without revealing any sensitive 

investigative details, these reports give Congress and the public meaningful insight into 

the frequency with which the government uses this surveillance technique and the kinds 

of climes that they are used to investigate. 

Last year, Congress received some dala regarding cell phone surveillance alkr 

Congressmen Batton and Markey wrote letters to the wireless carriers. Of the four largest 

carriers. three provided statistics in their responses (T-Mobile declined). revealing that 

they received 1.3 million requests from law enforcement agencies each year. However. 

only one company. Sprint Nextel. provided specific data about the location requests it 

receives. 

Congress cannot perfonn effective oversight of these invasive surveillance 

powers with data from only one of the four major wireless carriers. Furthermore. as the 

disclosures were in response to a specific request by two members of Congress, the 

wireless carriers are not obligated to provide updated data this year. 

Congress simply cannot pcrfonn elTective oven.ighL wiLhout dala. Por lhis reason. 

we urge the co-sponsors of the legislation to implement reponing requirements. 

Conclusion 

The ACLU agrees with Justice Alito that. in this time of rapid technological 

change, il is especially appropriate for Congress to step in and regulaLe the usc of 

surveillance technology by government. The warrant and probable cause requirements 

strike the appropriate balance. ensuring that legitimate investigations can go forward 

wilhoUL eroding the plivacy rights oC innocenl Americans. 

11 
43 

Mr. SENSENBRENNER. Thank you. 

Mr. Blaze? 

TESTIMONY OF MATTHEW BLAZE, PROFESSOR, 

UNIVERSITY OF PENNSYLVANIA 

Mr. BLAZE. First of all, thank you. Thank you, Chairman Sensenbrenner and Members of the Subcommittee, for the opportunity to 

testify here today. 

The focus of my remarks will be on the technology of mobile location tracking and the trends that we can expect mobile location 

technologies to follow as these devices become a more ubiquitous 

and critical part of our daily lives into the future. 

I think the most important thing for the Committee to consider 

in drafting legislation regulating the use of location information 

from mobile devices is that this is a very rapidly moving area of 

technology, enjoying continued and explosive growth. And that will 

continue for the foreseeable future and beyond. 

I’d like to talk for just a few moments about how cellular mobile 

devices operate. Of course, as you know, cellular telephones and 

cellular data devices, such as tablet computers, operate not with a 

wired connection, but rather with a radio connection. 

The radio connection is provided by a service provider that operates a network of base stations throughout its geographic coverage 

area. These base stations are alternatively called cell sites or cellular base stations or sometimes towers or sector antennas. The 

terms are approximately equivalent for our purposes here. 

Unfortunately, the capacity of any given base station is limited 

by two fundamental factors. The first and today less important one 

is the radio range over which they can operate. A cellular telephone 

under ideal conditions in a clear radio spectrum may be able to operate with a base station as far as a mile or two from the cellular 

handset. 

But the more important limitation is the spectrum capacity of 

the frequency bands that are used by the mobile service providers. 

Each base station has a limited number of calls that it can process, 

a limited number of data services that it can handle simultaneously from different customers. 

So as cellular and mobile technology has grown and become so 

important, as we all get different mobile devices and use them 

more often for more things, with higher bandwidth broadband connections, service providers have had no choice but to reduce the geographic area over which each base station operates so that smaller 

cell towers, smaller antennas cover a smaller number of users who 

can take advantage of the services that they’ve provided. 

And this trend has over the last 15 years been continuously in 

the direction of higher and higher density. We have provided more 

spectrum to mobile service providers, but the amount of spectrum 

is ultimately limited not by regulation, but by physics, and so really the only direction in which growth can happen at the explosive 

pace that it’s occurring is by making the base stations serve a 

smaller and smaller geographic area. 

One of the trends is the use of small cell sites that cover very 

small geographic areas, such as an individual home or an individual office. These are sometimes called microcells or picocells or 
44 

femtocells. Various service providers offer them. These may cover 

an area as small as this hearing room or our homes. 

Because of this increased density and because of this increased 

amount of usage, it’s become more difficult to meaningfully distinguish between cell site location and other geolocation technologies, 

such as vehicle-based GPS and precise location technologies that 

are used for E911 services, particularly if we consider how revealing this information is about our daily lives. 

Unlike vehicle-based GPS surveillance, we carry our cellular telephones with us everywhere we go. We have them on at all times. 

We take advantage of data services that cause them to send and 

receive data without us being aware that it’s occurring in many 

cases. And we can use them indoors and in private spaces, unlike 

GPS devices, which generally work only outdoors with a view to 

the satellite. 

And then, finally, the precision with which these can be located 

is increasing as the density improves, and that trend is going to 

continue because service providers have no choice but to improve 

density if they want to provide more services—— 

Mr. SENSENBRENNER. The gentleman’s time is expired. 

Mr. BLAZE. Oh, I’m sorry. My light wasn’t working. 

[The prepared statement of Mr. Blaze follows:] 
45 

House Committee on the Judiciary 

Subcommittee on Crime, Terrorism, and Homeland Security 

Hearing on ECPA, Part 2: Geolocation Privacy and Surveillance 

Written Testimony of 

Professor Matt Blaze 

April 25, 2012 

1. Introduction and Background 

Thank you for the opportunity to provide some background about location 

technology in current and emerging wireless networking. I hope my remarks 

will be helpful in understanding how location information is calculated and the 

direction that this important and yet rather complex technology is taking. I 

offer this statement today on my own behalf and do not represent any other 

party or organization. 

As I will discuss below, geolocation is an area that is enjoying a period of rapid 

technological innovation and competition among different technologies. Many 

assumptions that might have been true several years ago, such as that GPS 

satellites always provide higher precision location information than the cellular 

network does, are no longer universally true today. For any legislation that 

seeks to regulate the use or disclosure of location tracking technology to 

1 
46 

remain meaningful in the years to come, it is critical that it avoid defining 

terms in ways that are likely to become obsolete soon after it becomes law. 

In sum, my primary messages to policy makers considering how best to legislate 

in the area of location tracking are: 

The accuracy and precision with which a cellular telephone handset can 

be located by network-based (non-GPS) techniques depends on a range 

of factors, but has been steadily improving as technology has advanced 

and as new infrastructure is deployed in cellular networks. Under some 

circumstances, the latest generation of this technology permits the 

network to calculate users' locations with a precision that approaches 

that of GPS. 

A mobile user, in the course of his or her daily movements, will 

periodically connect to cell towers serving large and small geographic 

sectors. Even if the network only records cell tower data, the precision 

of that data will vary widely for any given customer over the course of a 

given day, from the relatively less precise to the relatively very precise, 

and neither the user nor the carrier will be able to predict whether the 

next data location collected will be relatively more or less precise. For 

a typical user, over time, some of that data will inevitably reveal 

locational precision approaching that of GPS. 

Network-based geolocation can often be more revealing than GPS 

tracking, because new and emerging cell location techniques can work 

2 
47 

indoors and in places not typically accessible to GPS receivers, and the 

increasingly high resolution that that cell site tracking can achieve in 

densely populated areas -- and the ability to provide this data even 

when the handset is indoors -- can paint an even richer picture of an 

individual's movements than GPS. 

I am currently an associate professor of computer and information science at 

the University of Pennsylvania in Philadelphia, where I serve as director of the 

Distributed Computing Laboratory and conduct research on computer security, 

cryptography, network communication, and surveillance technology. Prior to 

joining the faculty at Penn, I was for 12 years a member of the research staff 

at ATftT Labs (previously known as ATftT Bell Labs) in New Jersey. I have a 

PhD in computer science from Princeton University, a Masters degree from 

Columbia, and I completed my undergraduate studies at the City University of 

New York. 

A focus of my research is on the properties and capabilities of surveillance 

technology (both lawful and illicit) in the context of modern digital systems 

and communications networks. This research aims to strengthen our critical 

infrastructure against criminals and other unauthorized eavesdroppers and to 

help ensure that authorized surveillance systems work as intended in the 

rapidly changing environments in which they must reliably collect evidence and 

investigative intelligence. Sometimes, this work has led to surprising 

observations about real-world surveillance systems. For example, in 1994, I 

3 
48 

discovered weaknesses in the NSA's "Clipper" key escrow encryption system 

that led to that system's abandonment before it was widely deployed. More 

recently, my graduate students and I found previously undiscovered 

vulnerabilities in analog telephone wiretaps used by law enforcement, and we 

identified ways for law enforcement agencies to harden their CALEA intercept 

systems against a variety of surveillance countermeasures. 

There is perhaps no more ubiquitous symbol of our highly connected society 

than the cellular telephone. Over the course of only a few short decades, 

mobile communication devices have evolved from being little more than an 

expensive curiosity for the wealthy into a basic necessity for most Americans, 

transforming the way we communicate with one another, do business, and 

obtain and manage the increasing volume of information that is available to us. 

According to recent estimates, there are today more than 331 million active 

wireless subscriber accounts in the United States. Many households now forgo 

traditional "land line" telephone service, opting instead for cellular phones 

carried by each family member. Wireless carriers have strained to keep up 

with the explosive demand for cellular service, in many areas deploying new 

infrastructure (most visibly cellular antenna towers) as quickly as they can find 

places to put it. 

As difficult as it may be to imagine modern life without the cell phone, it is 

sometimes easy to forget how rapidly the technology has come about and how 

quickly new research ideas in wireless communication can advance into 

4 
49 

products and services that we take for granted. Over the last 25 years the 

mobile telephone has transformed from an analog voice·only service (originally 

available in only a few markets) into a high·bandwidth, always·on Internet 

access portal. "Smartphones", such as the latest iPhones and Android devices, 

act not just as voice telephones, but as personal digital organizers, music 

players, cameras, email readers, and personal computers, in a package that 

fits in our pocket. We now carry our phones with us wherever we go, and we 

expect them to have service wherever we happen to be. 

Many of the most important and innovative new applications and services that 

run on mobile devices take advantage of the ability to quickly and 

automatically detect the user"s location to provide location·specific 

information and advice. At the same time, cellular providers calculate where 

phones in their networks are located (and how they move) to manage various 

network functions and to plan where new infrastructure is required. 

5 
50 

2. Wireless Location Technologies 

Unlike conventional wireline telephones, cellular telephones and cellular data 

devices use radio to communicate between the users' handsets and the 

telephone network. Cellular service providers maintain networks of radio base 

stations (also called "cell sites") spread throughout their geographic coverage 

areas. Each base station is responsible for making connections between the 

regular telephone network and nearby cellular phones when they make or 

receive calls. Cell phone handsets periodically (and automatically) identify 

themselves to the nearest base station (that with the strongest radio signal) as 

they move about the coverage area. If a phone moves away from the base 

station with which it started a call and nearer to a different base station, the 

call is "handed off" between base stations without interruption. This process 

of "registration" between a phone and the nearest cellular base stations 

happens automatically whenever a cellular handset is turned on; no 

intervention by the user is required. The effect is that phones will generally 

work any time they are within radio range of at least one base station, which 

allows users to use their phone at any location in their provider's geographic 

coverage area. 

There are two different technical approaches that can be used for calculating 

the location of a cell phone. In the first approach, the user's phone calculates 

its own location using special GPS satellite receiver hardware built in to the 

handset. In the second approach, the cellular system infrastructure calculates 

6 
51 

the location of the phones that are active in the network, using the normal 

cellular radio interfaces and without explicit assistance from the users' 

handsets. 

2.1 Handset·based GPS 

For smartphone applications that run on the user's handset, the most 

prominent location technology is GPS. In GPS location, a user's phone contains 

special hardware that receives signals from a constellation of global position 

satellites. This allows a phone handset to calculate its latitude and longitude 

whenever it is in range of the satellites. GPS technology can achieve very high 

spatial resolution (typically within ten meters). In the latest phone models 

that incorporate GPS chipset hardware, GPS location features are integrated 

into applications for mapping, street directions, and to obtain information 

about local services and merchants. 

Whether or not the calculated GPS location of a handset is sent to the network 

(or any other third party) depends on the application software that the phone 

is running. Some applications, as a matter of course, may periodically transmit 

their location to external services. For example, a mapping application might 

send its current GPS-calculated location to a network-based service in order to 

discover, say, the locations of nearby businesses that might be of interest to 

the user. Network-based services that make use of a phone's GPS location 

7 
52 

might be offered by the cellular carrier or by a third party, internet-based 

entity_ 

Unfortunately, GPS, for all its promise, has a number of fundamental 

limitations_ It relies on special hardware in the phone (particularly a GPS 

receiver chip) that is currently included only in the latest handset models and 

that generally is enabled for location tracking only when the phone user is 

explicitly using it to run a location-based application on the phone_ Perhaps 

most importantly, GPS works reliably only outdoors, when the handset is in 

"view" of several GPS satellites in the sky above_ 

2.2 Network-based location 

GPS is only one technology for cell location, and while it is the most visible to 

the end user, GPS is neither the most pervasive nor the most generally 

applicable cellular phone location system, especially in the surveillance 

context. More ubiquitously available are techniques that (unlike GPS) do not 

depend on satellites or special hardware in the handset, but rather on radio 

signal data collected and analyzed at the cellular providers' towers and base 

stations. These "network-based" location techniques can give the position of 

virtually every handset active in the network at any time, regardless of 

whether the mobile devices are equipped with GPS chips and without the 

explicit knowledge or active cooperation of the phone users. 

s 
53 

The accuracy and precision with which a handset can be located by networkbased (non-GPS) techniques depends on a range of factors, but has been 

steadily improving as technology has advanced and as new infrastructure is 

deployed in cellular networks_ Under some circumstances, the latest 

generation of this technology permits the network to calculate users' locations 

with a precision that approaches that of GPS. 

Network-based location techniques work by exploiting the cellular radio 

infrastructure that communicates between the network and the users' phones. 

All cellular systems have an extensive network of base stations ("towers") 

spread throughout their areas of service such that a cell phone in any locations 

in the coverage area is within radio range of at least one base station. This 

arrangement essentially divides the carrier's coverage area into a mosaic of 

local "sectors", each served by an antenna at a local cellular base station. 

Network-based location enables a cellular provider to identify the sector in 

which a user's phone is located, and, in some cases, to further pinpoint their 

location within a sector. 

2.2.1 Sector identification 

At a minimum, cellular providers record the identity of the particular base 

station (or sector) with which a cellular phone was communicating every time 

it makes or receives a call and whenever it moves from one sector to another. 

How precisely this information by itself allows a phone to be located depends 

9 
54 

on the size of the sector; phones in smaller sectors can be located with better 

accuracy than those in larger sectors. 

Historically, in the first cellular systems, base stations were generally placed as 

far apart from one another as possible while still providing adequate radio 

coverage across the area terrain (effectively making the sector areas they 

cover as large as technically possible). In early cellular systems, a base station 

might have covered an area several miles or more in diameter (and in sparsely 

populated, rural areas, this may still be true today). But as cellular phones 

have become more popular and as users expect their devices to do more and to 

work in more locations, the size of the "typical" cell sector has been steadily 

shrinking. 

The reason for this trend toward smaller cell sectors is the explosive growth in 

the demand for wireless technology. A sector base station can handle only a 

limited number of simultaneous call connections given the amount of radio 

spectrum "bandwidth" allocated to the wireless carrier. As the density of 

cellular users grows in a given area, the only way for a carrier to accommodate 

more customers is to divide the coverage area into smaller and smaller sectors, 

each served by their own base stations and antennas. New services such as 3G 

and L TEl 4G Internet create additional pressure on the available spectrum 

bandwidth, usually requiring, again, that the area covered by each sector be 

made smaller and smaller. At the same time, users increasingly rely on their 

mobile devices to work wherever they happen to be, indoors and out, on the 

10 
55 

street, in offices and residences, even in basements and elevators. The only 

way to make service more reliable in more places under varying radio 

conditions is to add base stations that cover "dead spots". Adding base 

stations to eliminate dead spots further reduces the area of a typical sector's 

coverage. 

As a result of these pressures, the number of cellular base stations has been 

growing steadily, with a corresponding decrease in the geographic area served 

by each. According to a recent Cellular Telecommunications Industry 

Assodation (CTIA) study, the number of cellular base stations in the United 

States tripled over the most recent ten year period. Indeed, this trend has 

been accelerating rapidly, with the deployment of the latest generation of 

smaller and smaller-scale cellular base stations (called, variously, "microcells", 

"picocells" and "femtocells"). These small cells are designed to serve very 

small areas, such as particular floors of buildings or even individual homes and 

offices. By some estimates, the number of these small-scale cellular base 

stations equaled or outstripped the number of conventional cells in the US in 

2010, and their deployment continues to grow at a very fast rate. 

The effect of this trend toward smaller cell sectors is that knowing the identity 

of the base station (or sector ID) that handled a call is tantamount to knowing a 

phone's location to within a relatively small geographic area. In relatively 

unpopulated areas with open terrain, a sector might cover an area miles in 

diameter. But In urban areas and other environments that use microcells, a 

11 
56 

sector's coverage area can be quite small indeed, sometimes effectively 

identifying individual floors and rooms within buildings. 

2.2.2 Enhanced location with time- and angle- of arrival 

The decreasing size of cell sectors is not the only factor making cellular 

network-based location more accurate. New technology allows cellular 

network providers to locate not just the sector in which the users' wireless 

device is located, but its position within the sector. By correlating the precise 

time and angle at which a given device's signal arrives at multiple sector base 

stations, new technology now makes it practical for a network operator to 

pinpoint a phone's latitude and longitude at a level of accuracy that can 

approach that of GPS. 

A variety of "off-the-shelf" products and system upgrades have recently 

become available to cellular providers that use enhanced time- and/or angleof arrival calculations to collect precise location information about users' 

devices as they move around the network. Current commercially available 

versions of this technology can pinpoint a phone's location to an accuracy of 

within 50 meters or less under many circumstances, and emerging versions of 

the technology can increase accuracy even beyond that. This is accomplished 

without requiring any new or special hardware (such as GPS chips) to be 

installed on the end-users' phones. Accurate locations can be tracked with this 

technology even when no calls are being made or received, as long as the 

12 
57 

user's phone is turned on and is within a coverage area. (Whether locations 

are routinely tracked and recorded at times other than when calls are made or 

received depends on the policy of the particular carrier). 

Although these enhanced location technologies are not yet universally available 

in every network, wireless carriers are deploying them because they provide 

information that is extremely valuable in managing their networks and 

businesses. By tracking more precisely where mobile devices are located 

within sectors (and their patterns of movement), a carrier can better identify 

where new infrastructure might be required, where old infrastructure might be 

redundant, and how and where their customers use different service offerings. 

While each carrier has its own data collection and retention practices, carriers 

typically create "call detail records" that can include the most accurate 

location information available to them. Historically, before more advanced 

location techniques were available, carrier call detail records typically have 

included only the cell sector or base station identifier that handled the call. As 

discussed in the previous section, the base station or sector identifier now 

carries with it far more locational precision than it once did. 

As even more precise location information becomes available, cellular records 

increasingly (now and in the future) can effectively include what amounts to 

the customer's latitude and longitude along with the sector IDs traditionally 

used in cellular carrier databases. Some carriers will also store this location 

information not just when calls are made or received, but also about "idle" 

13 
58 

phones as they move about the network. Creating and maintaining detailed 

records about the locations of phones as they move from place to place makes 

good engineering sense, and we should expect the trend toward more, and 

more precise, location data collection to continue as part of the natural 

progression of commercial wireless technology. Once the infrastructure to 

collect it is installed, the marginal cost of collecting and storing high-resolution 

location data about every customer is relatively small. Such information will be 

collected because it is extraordinarily valuable for network management, for 

marketing, and for developing new services. 

14 
59 

3. Cell Phone Location and Law Enforcement Surveillance 

As noted above, even on networks that do not employ time-of-arrival or angleof-arrival location enhancements, the base station or sector location now 

identifies the location of a surveillance target with increasing specificity as 

cellular sectors become smaller and smaller and as microcells, picocells, and 

femtocells are being deployed to provide denser coverage. In legacy systems 

or in rural areas, a sector ID might currently specify only a radius of several 

miles, while in a dense urban environment with microcells, it could identify an 

individual floor or even a room within a building. How precisely the sector ID 

locates a target depends on the layout of the particular carrier"s network and 

where in the network the target is located, but the industry trend is moving 

inexorably toward sectors that cover smaller and smaller areas. 

Most carriers· systems use a variety of large and small sector configurations 

that vary based on the different terrain and densities they must cover. A 

mobile user, in the course of his or her daily movements, will periodically move 

in and out of large and small sectors. Even if the network only records cell 

tower data, the precision of that data will vary widely for any given customer 

over the course of a given day, from the relatively less precise to the relatively 

very precise, and neither the user nor the carrier will be able to predict 

whether the next data location collected will be relatively more or less 

precise. For a typical user, over time, some of that data will inevitably reveal 

locational precision approaching that of GPS. 

15 
60 

As cellular carriers roll out better location technologies in the course of their 

business, the location information sent to law enforcement (as transmitted 

from the carrier's call database in (near) real time in response to a wiretap 

order) is, inherently, becoming more and more precise. As sectors become 

smaller, the locational information they reveal becomes more intrinsically 

precise. And as networks improve, sector data is increasingly being linked to or 

supplanted by even more accurately calculated position information about each 

customer's handset. 

In the past, when cell sectors were widely spaced and before the availability of 

the enhanced network-based location technologies now being deployed by 

wireless carriers, it may have been technically sound to distinguish between 

location based on the cellular network (at presumably low accuracy) and that 

based on GPS (at higher accuracy). Today, however, this distinction is 

increasingly obsolete, and as cellular networking technology evolves, it is 

becoming effectively meaningless. As microcell technology and enhanced 

location techniques become more widely deployed in cellular networks, the 

information revealed by the cell sector identifier pinpoints, under many 

circumstances, a user's location to a degree once possible only with dedicated 

GPS tracking devices. It is no longer valid to assume that the cell sector 

recorded by the network will give only an approximate indication of a user's 

location. The gap between the location precision in today's cellular call detail 

records and that of a GPS tracker is cloSing, especially as carriers incorporate 

the latest technologies into their networks. 

16 
61 

Because the precision provided by cellular network-based location techniques 

approaches that of GPS-based tracking technology, cellular location tracking 

has significant advantages for law enforcement surveillance operations over 

traditional GPS trackers_ New and emerging cell location techniques can work 

indoors and in places not typically accessible to GPS receivers_ Cellular 

location information is routinely and automatically calculated by the network, 

without triggering any suspicious or alerting behavior on the handset that might 

be noticed by the subject- And the "tracking device" is no longer a hidden box 

that must be surreptitiously installed and that might be discovered, but a 

benign object that is deliberately carried by the target: his or her own 

telephone, computer, or tabletThese characteristics -- ubiquitous and continuous availability, lack of alerting, 

and high precision -- make network-based cellular tracking an extremely 

attractive and powerful tool for law enforcement surveillance. The increasingly 

high resolution that that cell site tracking can achieve in densely populated 

areas -- and the ability to provide this data even when the handset is indoors --

can paint an even richer picture of an individual's movements than can vehiclebased GPS devices. 

17 
62 

Mr. SENSENBRENNER. That light isn’t working. So sorry about 

that. 

Mr. BLAZE. Thank you, Mr. Chairman. 

Mr. SENSENBRENNER. Okay. The Chair will enforce the 5-minute 

rule during the question time and first recognizes the Chair of the 

full Committee, the gentleman from Virginia, Mr. Goodlatte. 

Mr. GOODLATTE. Thank you, Chairman Sensenbrenner, and 

thank you for holding this hearing. 

I regret that I wasn’t able to be here at the outset. So I am going 

to use my question time to offer my observations about geolocation 

issues, and I will start by saying that the Electronic Communications Privacy Act, or ECPA, provides a myriad of protections. Keep 

in mind that it was enacted well before our everyday use of cell 

phones and the Internet, yet ECPA sets forth the rules that prevent unauthorized Government access to certain electronic records. 

Even when it became law in 1986, ECPA, perhaps unintentionally, set the standards for the court-authorized disclosure of 

geolocation information. A suspect’s location is often only a piece of 

the puzzle for law enforcement, but sometimes that piece is a matter of life or death. 

In 2001, enhanced or E911 was deployed in the U.S. to associate 

a location with the origin of a phone call. Geolocation is critical in 

cases of child abductions, lost hikers, and missing Alzheimer’s patients where every minute counts. 

In many other investigations, geolocation is a vital building block 

in order to prevent or curtail a crime. Many criminals use false 

identities to impede law enforcement so they may complete their 

crimes and commit more. In every case, the identity of the criminal 

is essential for the investigation to move forward. The geolocation 

of dangerous fugitives is crucial, particularly after they are convicted of crimes like rape and murder. 

Today, many civil liberty concerns center on the abundance of 

new technological devices and a lag in the law keeping pace with 

this new technology. For instance, the law is well settled when it 

comes to police entering a home to arrest someone or conduct a 

search. However, complexities arise when, by the use of cell 

phones, we are permitting communication providers to record our 

location to route a phone call. 

We also allow them to record our location in order to advertize 

to us or send us instant coupons on our cell phones when we subscribe to a certain app. Cellular providers often use cell tower data, 

but also use GPS technology and our public Wi-Fi connections to 

determine where we are. 

In updating our Federal surveillance laws, Congress must weigh 

our privacy interests with the needs of law enforcement without 

stifling commerce and innovation. Last week, the Department of 

Justice briefed Judiciary staff on its current practices in seeking 

geolocation data. I was encouraged to learn that the department 

seeks a court order for every type of geolocation information it acquires. 

At a minimum, the department obtains what is called a 2703(d) 

Federal court order when it seeks historical cell site data on a particular cell phone. This cell site data only provides very general location information, which can vary widely. 
63 

On the other side of the spectrum, the Department of Justice obtains a search warrant from a Federal judge when it seeks very accurate real-time location information based on GPS satellite technology. Such search warrants are based on probable cause, the 

same standard specified in the Fourth Amendment to our Constitution. 

While these practices are encouraging, current DOJ practices do 

not carry the same weight as Federal statutes. The privacy interests we have in our cell phones are being protected today through 

a patchwork of Federal laws. Our task is to reexamine current laws 

and give clarity to individuals, corporations, innovators, and law 

enforcement. 

I look forward to working with my colleagues to examine 

geolocation privacy and surveillance. Our efforts must protect individual liberties by providing clear guidelines for when and how 

geolocation information can be accessed and used. 

And I thank Chairman Sensenbrenner and yield back. 

Mr. SENSENBRENNER. I thank the full Committee Chair. 

The Chair recognizes the Ranking Member, Mr. Scott of Virginia. 

Mr. SCOTT. Thank you, Mr. Chairman. 

Mr. Modaferri, you indicated—you talked about a crime where 

somebody committed seven robberies. Was any attempt made to get 

historic data at those locations to see if one person had been in all 

seven sites at the particular times? 

Mr. MODAFERRI. You mean a general subpoena for anybody in 

that area? No. 

Mr. SCOTT. Well, if you had—if you got a document—if you got 

a tower dump from the seven different sites and cross-referenced 

and found that only one person had been at all seven sites at the 

same time, is that—would that have been possible information to 

get? 

Mr. MODAFERRI. Not logically because all 7 robberies, the robberies were between 3 and 6 months apart in different locations in 

a tri-State area. 

Mr. SCOTT. How long is the tower information kept? 

Mr. MODAFERRI. That I don’t know. 

Mr. SCOTT. Anybody know how long tower information is kept? 

Mr. ECKENWILER. Ranking Member Scott, it varies according to 

provider. Some keep that information for a few months. Some keep 

it for up to a year or two. 

Mr. SCOTT. And so, if it was one of the services that kept it for 

a year or two, then you could have gotten information from the 

seven different locations. Is that true? 

Mr. ECKENWILER. If there were, in fact, network events that 

would be represented. Certainly when the records are available, 

the Government can compel them. Whether or not there would be 

a commonality across all seven of those locations is dependent not 

just on whether the phone was present, but whether there was an 

active communication like the sending or receipt of a text message 

or a phone call. 

Mr. SCOTT. The information that you are near a site is not recorded? 

Mr. ECKENWILER. When the Government obtains a tower dump 

that you referred to, what is produced is only a set of affirmative 
64 

network activities, like the receipt of a call. A phone call is answered. A phone call is placed. It does not reflect the presence of 

all phones that are simply on but not in active communication at 

that time. 

Mr. SCOTT. Is that because the information is not available or because it wasn’t—you can’t get it? 

Mr. ECKENWILER. It’s not the practice of the carriers to log that. 

There is not a real technical reason to retain information at that 

level of granularity. 

Mr. SCOTT. How expensive is it to the either law enforcement, if 

they pay for it, or the provider to provide a tower dump? 

Mr. ECKENWILER. I’d say a tower dump is fairly burdensome for 

the providers to disclose to law enforcement. And in practice, what 

often happens is law enforcement will obtain an order for a certain 

set of information, and there is often a negotiation, as there is in 

other cases—grand jury subpoenas and administrative subpoenas— 

to see if the scope of the request cannot be narrowed. 

Mr. SCOTT. Ms. Crump, we were talking about probable cause before you get all of this information. Probable cause is usually that 

a crime has been committed and the—what would be the standard 

after the crime has been committed to try to catch people? 

Ms. CRUMP. Are you contemplating the fugitive-type situation? 

Mr. SCOTT. Yes. 

Ms. CRUMP. I think that the civil liberties groups that support 

a probable cause requirement believe that in general the standard 

should be probable cause that a crime has been committed but also 

agree that it is important that fugitives be apprehended and don’t 

have an objection to cell phone location data being used in that circumstance. 

So a standard, for example, that there was an arrest warrant out 

for someone and that location information was useful to effectuate 

that arrest warrant is not something that anyone would object to. 

Mr. SCOTT. There is an expectation that the Government isn’t following you everywhere you go. How would you deal with emergency situations? 

Ms. CRUMP. We support an exception such as that in place in the 

GPS Act. Earlier, Mr. Goodlatte set out a number of examples of 

emergency situations—a child abduction, a lost hiker, and situations like that. I think everyone agrees that in those types of circumstances, it is important that law enforcement be able to act immediately and that if there’s not enough time to secure a warrant, 

that they should be able to proceed on an emergency basis and go 

ahead and locate someone. 

Mr. SCOTT. Thank you, Mr. Chairman. 

Mr. SENSENBRENNER. Thank you. 

The junior Chairman emeritus of the Committee, the gentleman 

from Michigan, Mr. Conyers? 

Mr. CONYERS. Well, I thank the senior Chairman emeritus for 

recognizing me. 

This is an unusual hearing in that I can’t remember ACLU ever 

quoting Justice Alito before, nor can I remember all of the emeritus 

being on the same bill of a Republican Member of the Committee, 

and the general agreement actually among the four witnesses. The 
65 

only difference of view that I have been able to note is the difference between a probable cause standard and a 2703(d). 

And I was wondering do you firmly hold to that, to the 2703(d) 

order, Mr. Eckenwiler? Or are you prepared to reluctantly go along 

with the probable cause standard that is in the bill? 

Mr. ECKENWILER. Mr. Conyers, I think, as Mr. Modaferri pointed 

out, one of the difficulties with adopting a probable cause standard 

for that less precise class of location data, cell site information, has 

significant potential to impair law enforcement investigations. 

Think of this as the building block of—it’s one of the building 

blocks for an investigation. In some cases, it may be used in conjunction with bank records. It may be used in conjunction with 

telephone toll records. There are various pieces that go into an investigation, especially at those earliest stages when probable cause 

has not yet been developed. 

And so, I think there would be significant costs to law enforcement if an across-the-board probable cause standard were to be 

adopted. But I would also refer you to the language I quoted earlier 

from Jerry Berman, the executive director of EFF, testifying before 

joint House/Senate Judiciary Committee hearing. 

Pointing out that the 2703(d) standard is, in fact, meaningful, 

Mr. Berman pointed out in his testimony court order protection will 

make it much more difficult for law enforcement to go on fishing 

expeditions. And he pointed out in that same testimony that law 

enforcement would have to meet this particular showing, this need 

to establish access to these records based on specific and 

articulable facts. 

So law enforcement has to tell a story. It’s not like certain other 

kinds of compulsory process, a grand jury subpoena, which merely 

issues from the prosecutor. It’s not like a pen register order to monitor the noncontent activity on, say, a telephone line, the numbers 

dialed out or in. Those kinds of orders, under the existing statute, 

simply require a certification to a judge, who has no discretion. 

2703 is different. A factual showing has to be made to the court, 

which the court may then weigh and, based upon that weighing of 

the showing, may grant or deny the application. 

Mr. CONYERS. Professor Blaze, I know you have a slightly different view? 

Mr. BLAZE. So I think this is one of the areas where Mr. 

Eckenwiler and I disagree. The gap between these different technologies is narrowing, I think, sufficiently that we can’t really 

make meaningful distinctions between how revealing they are. 

So if we understand GPS location technology to be revealing 

enough to warrant one standard, I don’t see any technological basis 

to understand cell site location as being sufficiently less precise or 

less revealing to merit a different standard. 

The gap is narrowing in how precise they are, and in some cases, 

cell site location can reveal location information when vehicle-based 

GPS would be unable to, such as when the target is indoors. 

Mr. CONYERS. Well, I guess the probable cause standard based 

on the Fourth Amendment is more compelling. But you know, 

when you read these off the top, Chairman Sensenbrenner, you 

could probably use either one to accomplish your goal. 

And I thank you for the time. 
66 

Mr. SENSENBRENNER. I thank the gentleman from Michigan. 

The gentleman from Louisiana, Mr. Richmond? 

Mr. RICHMOND. Thank you, Mr. Chairman. 

Let me see, my first question, and I guess I will direct this question to Ms. Crump. Do cell phone users ever find out that their 

geolocation information has been divulged? 

Ms. CRUMP. Thank you for the question. 

That highlights one of the key problems with this form of tracking. On occasion, cell phone users do learn that they are tracked. 

But in order for that to happen, in general, they have to be prosecuted, and then that evidence has to be used in the case-in-chief. 

That means that whenever someone is tracked and they are innocent or the Government chooses not to disclose that information, 

individuals never learn they were subject to that technique. That 

has had the effect of meaning that for a long time, the Government’s policies and procedures for engaging in cell phone tracking 

have been shrouded in secrecy. 

And we believe that it’s important that individuals who are subject to this form of surveillance receive notice, at least after the fact 

when the investigation is closed, because that will increase the 

public’s awareness and information about how the Government is 

balancing civil liberties and law enforcement interests. 

Mr. RICHMOND. Now is that—is your position pretty consistent 

with what they do with wiretaps? 

Ms. CRUMP. Yes, that’s true. 

Mr. RICHMOND. So after a wiretap, they do disclose to the person 

that they were subject to a wiretap? 

Ms. CRUMP. Yes. That’s the case. 

Mr. RICHMOND. Do they also disclose that to the person who may 

have been on the phone with someone on a wiretap that they 

were—that their call was intercepted or that you all don’t do that? 

Do you know that, Mr. Eckenwiler? 

Ms. CRUMP. The answer—oh. 

Mr. ECKENWILER. Yes. The—in general, the requirement under 

Section 2518 of Title 18 requires that notice be given. Often the 

court may direct the scope of the disclosure, but it is not simply 

limited to the person who is named in the wiretap order. 

So, in direct response to your question, yes, other communicants 

with whom that person has, say, spoken on the phone would also 

typically receive notice. 

Mr. RICHMOND. Is there a timeframe on that notice or—— 

Mr. ECKENWILER. The statute, Title III, the Wiretap Act currently says that the—what’s called the inventory must be given 

within 90 days after the termination of the wiretap, although the 

delay of notice may be extended for good cause shown to the 

issuing court. 

Mr. RICHMOND. And I don’t know if we discussed it, but I will 

go back to you, Ms. Crump. What standard do you think should be 

applied to the one-time ping or the real-time looking at where a 

person is once? 

Ms. CRUMP. Our view is that a one-time real-time tracking ping 

should also require probable cause. The reason for that is you do 

not know, generally speaking, when you conduct that ping whether 

someone is going to be in a, for instance, a private place where 
67 

they have a reasonable expectation of privacy. And the better rule 

is a probable cause requirement across the board. 

Mr. RICHMOND. We have mentioned a couple of times about reasonable expectation of privacy, and I guess as technology evolves, 

at some point, do you think there is going to be a discussion that 

if you have your cell phone with you, you probably don’t have a 

reasonable expectation of privacy? 

Ms. CRUMP. No. I don’t think people should have to give up their 

privacy rights simply because today’s modern era essentially requires people to have a cell phone in order to participate. It has 

traditionally been the case that individuals have been able to move 

around public and private places without being subject to the continuous monitoring and permanent recording of their movements. 

I think that’s an important freedom and that it shouldn’t be sacrificed just because we now have cell phones. 

Mr. RICHMOND. Well, you mentioned the recording of their movements, and I guess that one is probably a lot easier than the realtime where you are. And I wouldn’t want anyone recording my 

movements, but do I have a reasonable expectation of privacy that 

if I was in the audience, no one would know I was here? 

I mean, as it evolves, the question is how realistic it becomes and 

how reasonable that expectation is? And that is why I pose it because at some point, I think that question will become very relative 

to all of the conversations that we have in terms of our privacy. 

Mr. Eckenwiler, did you want to add to that? 

Mr. ECKENWILER. It’s certainly true, Congressman Richmond, 

that there are different kinds of location data, many of which are 

overtly public. People who post on social media and choose to turn 

on their location disclosure feature, I think it would be abundantly 

clear that there is no expectation of privacy that attaches to that 

kind of location information. 

Mr. RICHMOND. I thank you, and I yield back, Mr. Chairman. 

Mr. SENSENBRENNER. I thank you. 

The gentlewoman from California, Ms. Chu? 

Ms. CHU. Thank you, Mr. Chair. 

For the panel, I would like to ask this question. We trust law enforcement to use their own discretion in deciding whom to physically follow around for extended periods of time. Why can’t law enforcement be trusted to exercise their discretion when engaging in 

similar tracking using GPS systems or cell phones? 

Isn’t using electronic tracking just more efficient, or is there 

something fundamentally different about electronic tracking? Ms. 

Crump? 

Ms. CRUMP. Thank you for the question. 

There is something fundamentally different about electronic 

tracking. Physical tracking is by necessity limited by officer resources. And because that form of tracking requires the expenditure of tremendous resources, that itself acts on a check against 

abusive forms of that tracking. 

In contrast, electronic tracking is wholly concealed. Individuals 

don’t know it’s happening, but it can also be done in a very resource-efficient way, which means that legal protections against it 

are all the more important. 

Ms. CHU. Mr. Blaze? 
68 

Mr. BLAZE. If I might just add to that? And the electronic tracking, unlike physical surveillance, follows us wherever we go, particularly cell phone-based electronic tracking. 

It follows us indoors into private spaces, in places where physical 

surveillance would be unable to track somebody, at least 

undetectably. So there is a technological distinction as well. 

Ms. CHU. Thank you. 

Mr. ECKENWILER. Thank you for the question, Congresswoman 

Chu. 

I agree that a probable cause standard is appropriate for realtime GPS or other precise location data. Let me give you a couple 

of reasons. 

One is that it is not event based. Cell site information is derived 

from specific overt user activity, a call, the sending of a text message. And so, that’s generated in the network. The network has to 

know about that. 

The network can’t not know about it anymore than I can dial a 

phone number without telling the phone company what number I 

want to call. It just is an innate part of the transaction. But the 

acquisition of precise location information may be done, as I indicated in my opening remarks, even when there is not an active 

communication in progress on the device. 

What’s also I think significant here, even before anybody had cell 

phones, the Supreme Court indicated in a case in the early 1980’s 

with respect to physical tracking devices that when a tracking device actually reveals the presence of something within a protected 

area that’s not otherwise observable by the police, that that can implicate a reasonable expectation of privacy. That’s the Karo case, 

K-a-r-o. 

Now there’s an important distinction here, and that is between 

whether the item is merely in a protected area or whether the information about it reveals that it’s there. So it’s not just enough 

that something is in some area at the time that location data like 

cell site is acquired. But if the information is so precise as to place 

it inside a particular home, which is what happened with the physical GPS tracker in Karo, then, yes, indeed. If you apply that same 

logic to cell phone GPS, it would follow that there’s an expectation 

of privacy. 

Ms. CHU. Yes, in fact, I wanted to follow up by saying that the 

majority opinion in Jones found that a search occurred because law 

enforcement had committed a trespass by fixing this GPS tracking 

device to a private vehicle without a valid warrant. Does that 

means there is less of a concern when location tracking is done 

without fixing a device, such as using cell phone location data? 

Ms. Crump? 

Ms. CRUMP. No, I don’t think there’s any less of an expectation 

of privacy. The one opinion did focus on trespass, but five other justices focused on the nature of the intrusion of being tracked. To be 

sure, that case involved attachment of a GPS device, but I don’t 

think, practically speaking, whether the technological method is attachment of a GPS device or a cell phone makes any difference. 

Although I’m always glad when there’s agreement between the 

Department of Justice and the ACLU on a question, however we 

get there, I do think the distinction between whether the location 
69 

data is generated by the network or an act of intrusion into the 

phone is overly formalistic, and the more common sense approach 

is to focus on the privacy intrusion and what people’s expectations 

are. 

Mr. SENSENBRENNER. The gentlewoman’s time has expired. 

And the Chair yields himself 5 minutes to wrap up. 

Last year, the court handed down the Jones decision, and about 

the only thing the justices could agree upon was that there was a 

search that occurred. And then they were all over the map under 

what circumstances, a judicial review, and I don’t want to talk 

about what type of specific review would be or what kind of warrant or 2703 device would be. 

But I would like to each ask of the witnesses whether they think 

it would be wise for Congress to try to set some markers on what 

needs to be done in advance, if anything, with various types of use 

of GPS equipment, or the topic of our first hearing on ECPA, largely to prevent a court decision from coming down years from now 

which might reopen or place in jeopardy cases that already had 

been filed. 

And I would like to ask each of the four witnesses to answer that 

question. Meaning do we need a bill, and what should the bill contain? 

Mr. ECKENWILER. Thank you, Mr. Chairman. 

Just so I understand the question, is this directed to physical 

GPS, or do you still have in mind phone GPS? 

Mr. SENSENBRENNER. Both. 

Mr. ECKENWILER. As to physical GPS, such as that that was at 

issue in the Jones case, it seems to me the Supreme Court has laid 

down a pretty clear marker, and there is already—at least in Federal Rule 41, there has been since 2006 a set of procedures for applying for and obtaining a warrant to install and use a physical 

tracking device. So it’s not clear to me that there’s a particular 

need for this Committee to act in that area. 

Mr. Chairman, you mentioned prior cases, cases that may have 

been investigated or charged prior to a particular court decision. 

What’s interesting is that in the roughly 14 months, 15 months 

since Jones came down, that issue has come up across the country 

in various courts. And generally speaking, Jones has not resulted 

in the suppression of evidence for pre-Jones law enforcement conduct. The short answer is there’s a good faith exception. 

And then to respond briefly to your question about phone location information, I would simply reiterate what I said earlier. I 

think that would come at significant expense to important law enforcement equities. As to cell site location information, I don’t think 

that it would be inappropriate at all to clarify, and in fact, I’ve 

mentioned in my list of areas for the Committee’s further inquiry 

the potential need to amend Rule 41 for prospective GPS acquisition on phones. 

Mr. SENSENBRENNER. Mr. Modaferri? 

Mr. MODAFERRI. Thank you. 

I would say that from my perspective as a detective, we do need 

clarification. We do need an act to clarify what Mr. Eckenwiler’s— 

the points that Mr. Eckenwiler made because we are acting some-
70 

*See Appendix. 

what in the dark in certain areas. And as technology evolves, we 

need a law that can address things as it changes. 

But I wouldn’t—I’m not a lawyer so I won’t get into the details 

of Mr. Eckenwiler. 

Mr. SENSENBRENNER. Ms. Crump? 

Ms. CRUMP. The short answer to your question is, yes, it is essential that Congress act. It took many years for the court to even 

reach the Jones decision. GPS tracking had been going on for a 

long time, and it only partially answered the question. And it’s important that this body step in and clarify the law so that everyone 

understands what their rights are. 

Second, I think law enforcement and civil liberties organizations 

such as the ACLU at the least agree that the current system is unclear and in a state of chaos with judges applying different standards to identical forms of tracking in different States and that it’s 

important that the law be uniform. 

Mr. SENSENBRENNER. Mr. Blaze? 

Mr. BLAZE. Thank you. 

I’m also not an attorney. So I will answer from the technical perspective. Any legislation that attempts to distinguish between the 

revealing and intrusiveness of vehicular GPS, precise cellular 

geolocation, and cell site geolocation will be doomed to become increasingly meaningless as those technologies converge in their precision. 

Mr. SENSENBRENNER. That concludes this hearing. 

Without objection, all Members will have 5 legislative days to 

submit additional written questions for the witnesses and additional materials for the record. 

The gentleman from Virginia? 

Mr. SCOTT. Mr. Chairman, I ask unanimous consent that a law 

review article by Stephanie Pell, published in the Berkeley Technology Law Journal, be entered in the record.* 

Mr. SENSENBRENNER. Without objection. 

And without objection, the hearing is adjourned. 

[Whereupon, at 11:06 a.m., the Subcommittee was adjourned.] 
(71) 

A P P E N D I X 

MATERIAL SUBMITTED FOR THE HEARING RECORD
72 

Material submitted by the Honorable Robert C. ‘‘Bobby’’ Scott, a Representative in Congress from the State of Virginia, and Ranking Member, Subcommittee on Crime, Terrorism, Homeland Security, and Investigations 
73 

CAN You SEE ME Now?: 

TOWARD REASONABLE STANDARDS FOR LAw 

ENFORCEMENT ACCESS TO LOCATION DATA 

THAT CONGRESS COULD ENACT 

Stephanie K Pelt c':- Christopher S oghoianlT 

ABSTRACT 

The use of location information by law enforcement agencies is common and becoming 

more so as technological improvements enahle collection of more accurate and precise 

location data. The legal mystery surrOlmding the proper law enforcement access standard for 

prospective location data remains unsolved. This mystery, along with conflicting mhngs over 

the appropriate law enforcement access standards for both prospective and historical location 

data, has created a messy, inconsistent lcgallandscape where even judges in the same district 

may require law enforcement to meet different standards to compel location data. As courts 

struggle with these intertwined technology, privacy, and legal issues, some judges are 

expressing concern over the scope of the harms, from specific and personal to general and 

social, presented hy unfettered govenuuent collection and use of location data and how to 

respond to those hmms. Judges have sought to communicate the scope and gravity of these 

concerns through direct references to Orwell's dystopia in 1984, as well as suggestive 

allusions to the "panoptic effect" observed by Jeremy Bentham and his later interpreters, 

such as Michel Foucault. Some have gone on to suggest that pl~vacy issues raised by law 

enforcement access to location data might be addressed more effectively by the legislature. 

This ~I\rticle proposes a legislative model for law enforcement access standards and 

downstream privacy protections for location in£:mnation. This proposal attempts to (1) 

articulate clear mles for courts to apply and law enforcement agents and industry to follow; 

and (2) strike a reasonable balance among the interests of law enforcement, privacy, and 

industry with the ultimate goal of improving the position of all concerned when measured 

against the current state of the law. 

(c) 2012 Stephanie K. Pell & Christopher Soghoian. 

t Principal, SKP Strategies, LLC; former Counsel to the House Judiciary Committee; 

former Senior Counsel to the Deputy ~I\ttorney General, U.S. Department of Justice; former 

Counsel to the Assistant i\ttomey General, National Security Division, C.S. Department of 

.Iustice; and former ~I\ssistant U.S. Attorney, Southern District of Florida. Email: 

stephanie@stephaniepell.net 

tt Graduate Fellow, Center for Applied Cybersecurity Research; PhD. Candidate, 

School of InfOimatics and Computing, Indiana Cniversity. Email: chris@soghoian.net. 

The authors 1N0uld like to thank Derek Bambauer, Catherine Crump, Susan 

Freiwald,.Iim Green, jlJbert Gidmi, Markus .Jakobsson, Paul Ohm, Christopher Slobogin, 

and Magistrate Judge Stephen Wl1l. Smith for their feedhack and assistance. The authors 

would also like to thank the attendees of the Privacy Law Scholars Conference, where this 

Article was presented in the summer of 2011. 
74 

118 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

TABLE OF CONTENTS 

1. INTRODUCTION ............................................................................................. 119 

11. TECHNOLOGy ................................................................................................. 126 

A. A BRlb:F TN'j'RODLCI'ION 'J'() Cb:I.I, PHON Ii T~:CHNOLO(~Y .............. 126 

B. CELL SIn: DATA ........................................................................................ 128 

C. GLOBAL POSITIONING SYSTEM ("GPS") .............................................. 128 

D. WIFI .............................................................................................................. 129 

E. PINes ........................................................................................................... 131 

F. TRENDS ........................................................................................................ 132 

TH. THE LAW ............................................................................................................. 133 

A. L~(;AL BACKGROLIND FOR REAL-TL\lE OR "PROSPEcnVE" 

CELL SIn: DATA ........................................................................................ 134 

1. The DOl's I1?terptrt"tio1? of the Stm?limdfor Obtainil1g 

ProJpective Gell Site Data ................................................................... 135 

2. Judici,,! ReslJ-ta1?Ce to the Government'J- Use of Hybrid Orden .. ........... 13 7 

3. Dil'ergent Interpretations o/tlle Stm/dard jor 

Disclosm" ofPmJpectit!e Cel! Site Data Create Lega! 

U/'lCf/14i/'ity ........................................................................................ 139 

B. LEGAL BACKGROUND POR HISTORICAL Cr::LL SITE DATiL ............. 141 

1. The DOl's Irzterptrt"tio/'l of the Sta1?dmd for Obtainil1g 

HiJ-ton,-a! Ge!! Site Data .. .................................................................. 142 

2. Jlldicia! ItztflpretatiolZ of the Standardfor Obtainifl,g Historical 

C'ell Site Data ................................................................................... 143 

a) The Third Circuit Finds That Magistrate Judges 

Have the Discretion To Require Probable Cause ........ 143 

b) The D.c. Circuit's ":',;[osaic Theory" ............................... 145 

3. The Jones DedJ-ion ........................................................................... 148 

4. FIx Importance (If I /igl~r/atit'e Glarity in tbe /-<ace of l\apid 

TedJlZolo,gica/ Chm;ge ..................................... ..................... .. .. 150 

C. QlIb:s'j'IO'JS RAlsb:!) HY 'l'He: Two FXIS'J'I'Jc; SI At'--DARDS 

FOR COMPELLING DISCLOSURE OF LOCATIOK DATA ....................... 151 

1. /.f;7JJat Does a "D" Order Req7iire!be GOlJemment To Shot}}? ............ 151 

2. Probable Cat/se of What? .................................................................... 154 

IV. LESSONS LEARNED ...................................................................................... 157 

A. ACQUTRTNC-; bilCTS To MAKE Goon Pm.TCY Is DTFFTCCT.T ........... 157 

B. TIlE SINGULAR ADVOCACY Focus ON LAW EKFORCEMENT 

S'j'A'JDARDS HAS NARROWb:D II DISCliSSIO'J THA'!' SHOLLD 

INCLUDE MINIMIZATIO"l AND OTHER "DO\vNSTRr::AM" 

PRIVACY PROTECTIOKS ........................................................................... 160 
75 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 

C. THE POLARIZED VIEWS OF LAW ENFORCEMENT AND 

PRIVACY ADVOCATES NLAKE CONSEKSUS BUILDI"lG 

119 

DIFFICUL'I ................................................................................................... 161 

V. WHAT IS THE HARM, AND WHO CAN ADDRESS IT 

MOST EFFECTIVELY? .................................................................................. 163 

A. THE GOVERKMENT'S GAZE A"lD THE PA'\"OPTIC El'lECT.. ............. 164 

\iI. LEGISLATIVE PROPOSAL.. ......................................................................... 174 

/1.. OVERARCHING PRINCIPLES ..................................................................... 175 

1. Clear RuleJ' ......................................................................................... 175 

2. TedJtlohgy Neutmlity ......................................................................... 176 

3. Standards Alone IF'll! Not Achieve the Appropriate Balance .............. 176 

4. ],mJ'teJ1ce 011 a Sil1gle LocatiON S taJ1dard lJ 

"A Foolish ..................................................................... 1 77 

B. How To DEFINE LOCATIOK INFORMATION FOR PURPOSES 

OF A \fENDTNG THE ECP A ................................................ .. .. .. 178 

C. A STANDARD FOR LAW ENFORCEME"lT COMPELLED 

DISCLOSURHS OJ:< HISI ORICAL LOCATION DA'LA ............................... 180 

D. A STANDARD l'OR LAW ENl'ORCEME"lT COMPI:LLED 

DISCLOSURES OF PROSPECTIVE LOCATION DATA ............................ 181 

E. POST ACCESS RULES AKD ''DOW'KSTREAM'' PRIVACY 

PROTECTIOKS......................................................................... .. .. 183 

1. Minimizatioll.................................................................. .. .. 184 

2. Notification ......................................................................................... 185 

3. S Nrl1elliallce S tatiJ,tics .......................................................................... 188 

VII. CONCLUSION ................................................................................................... 193 

I. INTRODUCTION 

Over several months in 2008, a gang of five men, described as the 

"Scarecrow Bandits" in media reports, committed or attempted twenty-one 

violent "takeover-style" bank robberies in the Dallas area. 1 FBI agents 

investigating the case contacted cellular telephone companies and obtained 

phone number logs to determine which telephones had been near tile banks 

around tile time of the heists. Dy searching these voluminous records, agents 

discovered that two phones had made calls near twelve of the robbed banks.2 

1. See Press Release, Dep't of Justice, Federal Jury Convicts Scarecrow Bandits on 

Bank Robbery and hrearm Offenses (Aug. 13, 2009), http://www.justice.gov/usao/txn/ 

PressRel09/ scarecrow _handits_com,;c t_pr.h tml. 

2. See Declan ".1cCullagh, Feds Push}Or Tradeing Gil Phones, CNET NEWS (Feb. 11, 

2010), http://news.cnet.com/ 8301-13578_3-10451518-38.html. 
76 

120 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

Similarly, after two men robbed a Connecticut bank in July 2008, law 

enforcement agents obtained historical cell tower logs revealing 180 different 

phone numbers that had made or received calls ncar the bank at the time of 

the rohhery. Although these logs led police to two hrothers, hoth of whom 

were soon arrested, the police also obtained and retained location 

information associated with 178 innocent people who will never learn that 

their phone companies disclosed information to police." 

Law enforcement agencies-already using location information in their 

investigations-are likely to increase their reliance on such information as 

technology improves. 4 This is tnJe of requests for all types of mobile device 

location data, whether historical or real-time (prospective),S in conducting 

criminal investigations and locating fugitives. For example, primarily due to 

the use of location infonnation, the average time needed for the U.S. 

~farshals Service to find a fugitive has dropped from forty-two days to only 

two. 6 In recent congressional testimony, a senior Department of Justice 

("DO]") official explained how a homicide detective and his partner in 

Prince George's County, Maryland, used "cell tower Qocation] information" 

to pursue a man wanted for a triple murder, capturing him in only nine 

hours.7 Having this information "immediately accessible" allowed the 

marshals to deploy "available law enforcement resources [effectively] ... 

\vithout placing officers, or the public, at undue risk."s Clearly, location 

information has hecome a powerful investigative tool in support of a range 

of law enforcement responsibilities." 

3. See Declan McCullagh, /lCLU: FBI Used 'Dragnet'-Style 1,f7arrantfess eell Trackillg, 

CNET Nl2ws (Tune 22, 2010), http://news.cnet.com/S301-31921_3-20n0il444-2S1.htmL 

4. A more technical explanation of location infonnation is presented in/ra Part II, but 

for purposes of this example, location information means information about or derived from 

a portable device, such as a cellular phone, that reveals the location of the dev-ice either 

approximately or with a high degree of precision. 

S. McCullagh, supra note 2 ("Obtaining location details is now 'commonplace,' says Al 

Gidari, a partner in the Seattle offices of Perkins Coie who represents wireless carriers.')' 

6. See Goil!1!. Dark: Electrollic SUl7JezllmlCe ill the Face of New Tec!moIQrjes: Hemil\[l, 

Tlefom the Subcomm. all Crime. at!d Homeland Security of the H. COtJ1l!l. ot! the judiciary, 

112tll Cong. 2 (2011) (statement of Dr. Susan Landau), available at http://judiciary.house. 

gov/hearings/ pdf/Landau02172011.pdf. 

7. The Electronic LommlmicationJ Plil'ary Ali: CUZ!e17111le11t Pmpedil!eJ" on Prutafing Piil!ary in 

the Digital Age: Hearing befom the S. Comm. 011 the judiciary, 112tll Congo 5 (2011) ~lereinafter 

Senate judiciary 2011 FlCPA Heariti;g] (statement of Junes i\. Baker, Assoc. Deputy i\ttomey 

Gen., U.S. Dep't of Justice), al)ailabfe at http://1.usa.gov /lsojNy. 

S. Id 

9. See Michael Isikoff, The Snitch ill Your Pocket, NEWSWEEK (Feb. 18, 2010), http:/ / 

www.newsweek.com/2010/02/18/the-snitch-in-your-pocket.htm!. 
77 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 121 

The tool proved so effective that the number of "requests,,10 to carriers 

for location information grew "exponentially" over the past few years, with 

major wireless carriers now receiving thousands of requests per month.ll 

Sprint Nextel received so many requests that it developed a weh interface 

that gave law enforcement direct access to its subscribers' location data. '2 

Law enforcement agents used the website to "ping" Sprint subscribers over 

eight million times in a single year.13 

Law enforcement's increased use of location information has spurred 

courts to scrutinize more closely government applications to compel third 

parties to disclose location data, as certain magistrate judges question and 

examine what legal standards govern law enforcement access to historical 

and prospective location information. Prosecutors "were using the cell phone 

as a surreptitious tracking device," Judge Smith, a federal magistrate in 

Houston, told a reporter from Kewsweek. "I started asking the U.S. 

Attorney's Office, Wbat is the legal authority for this? Wbat is the legal 

standard for getting this information?"14 

All law enforcement demands (not involving voluntary emergency 

disclosures) for location information, whether seeking historical or 

prospective data, require some type of court order authoriL:ing a compelled 

disclosure. 15 Determining the proper access standard-whether the higher 

"prohahle cause" standard, the ImlJer lR USc. § 2703(d) order requiring 

"specific and articulable facts" that the information sought is "relevant and 

10. The use of the word "requests" in this context means both compelled disclosures 

of location infonnation where law enforcement presents a third-party provider with a 

probable cause warrant or an 18 C.s.c. § 2703(d) order and voluntary emergency disclosures 

pursuant to 18 U,S,C § 2702, where providers may voluntarily share infonnation with law 

enforcement in the case of an emergency involving danger of death or sel~ous physical injury 

to any person. 

1 L Tsikoff, supra note 9 ("Albert Gidari, a telecommunications lawyer who represents 

several wireless providers, tells NEWS\\iEEK that the companies arc now getting 

'thousands of these requests per month,' and the amount has grown 'exponentially' over the 

past few years."). 

12. Chief Judge Kozinski, in a dissent in which he stressed the importance of 

maintaining Fourth Amendment protections in the face of increasingly sophisticated fonns 

of government surveillance, noted that "lwJhen requests for cell phone location information 

have become so numerous that the telephone company must develop a self-service website 

so that law enforcement agents can retrieve user data from the comfort of their desks, we 

can safely say that 'such dragnet-type law enforcement practices' are already in use." Cnited 

States v. Pineda-Moreno, 617 F.3d 1120, 1126 (9th Cir. 2010) (Kozinski,]., dissenting from 

denial of rehearing en bane). 

13. Id at 1125. 

14. See Isikoff, supra note 9. 

15. See discussion itlji-a Sections IILA and IILB. 
78 

122 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

material to an ongoing criminal investigation,,,lG or some other "hybrid" 

standard-is anything but clear under current law. As various courts struggle 

to apply the Electronic Communications Privacy Act ("ECPA"t and the 

Fourth Amendment to compelled disclosures of location information, a 

messy, inconsistent legal landscape has emerged: "within the same judicial 

district, you might have nevo magistrates who disagree and issue contrary 

orders for the standard upon which to disclose that flocationl infonnation."18 

Indeed, the degree of confusion over the appropriate standard to apply to 

location information is increasing and has spread across judicial districts.19 

The House Judiciary Committee's Subcommittee on the Constihltion, 

Civil Rights, and Civil Liberties began to respond to this landscape of 

uncertainty in 2010 by holding a series of ECPA refonn hearings, one of 

which focused specifically on location infonnation. 20 Prior to the hearings, a 

16. 18 U.s.C § 2703(d) (2010). 

17. Puh. L. No. 99-508, 10n Stat. 1848 (1986) (codified as amended in scattered 

sections of 18 U.s.C). This Article uses the terrn ECPA to describe the first three titles of 

the Electronic Communications Privacy Act: Title I ("Interception of Communications and 

Related Matters''), 100 Stat. at 1848, which amended the Wiretap Act (commonly referring 

to Title 111 ("Wiretapping and Electronic Surveillance") of the Omnibus Crime Control and 

Safe Streets Act of 1968, Puh. L. No. 90-351, tit. III, 82 Stat. 197, 211-25 (codified as 

amended at 18 U.s.C §§ 2511-2520 (2010»); Title II ("Stored Wire and Electronic 

Communications and Transactional Records Access"), commonly referred to as tl,e Stored 

Communications Act (SCA), Pub. L. No. 99-508, tit. II, 100 Stat. 1848,1860-1868 (codified 

as amended at 18 U.s.C §§ 27Ul-2712 (2UlU»; and Title III ("Pen Registers and Trap and 

Trace Dev-ices"), commonly referred to as the Pen/Trap Devices stahlte, Pub. L. No. 99-

508, tit. III, 100 Stat. 1848, 1868-1873 (codified as amended at 18 U.s.C §§ 3121-3127 

(2010». 

18. Ele,1rvnic CommunicationJ PrilJary Ad Reform: Hearing Beforp tbe Submmm. at! tbe 

Constitlltion, Gvil RjghtJ~ and Gvil Lbetties of the H. COllll1l. on the Judiciary, 111 th Congo 26 (2UlU) 

~lereinafter House Judiciary 2010 TJCPA Reform Hemillg! (written statement of i\lbert Gidari, 

Perkins Coie LLP), available at http://judiciary.house.guv/hcanngs/printers/l11th/111-98_ 

56271.pdf. 

19. See generally ECPA ReJunn and the Nl'oblfion in Location Based TeihrlOlogieY and Sen'im: 

Hem711!', Before tbe j'tlbcomm. on the Constitution, Chil H4l!,btJ~ al2d Cil~il Liberties oj the H. COlllm. on the 

]lIdi.Cl~Jry, 111 th Congo 81-85, 93-94 (2010), ~lere.inafter T LJcdtiorz HetJtiri;g] (written statement 

ofludge Stephen Wm. Smith, U.S. Magistrate .Judge), avm/ab!e at http://judiciary.house.guv/ 

heari.1lgs/ printers /111 th/ 111-109 _S7082.pdf (summarizing and collecting llcomistent 

decisions) . 

20. See Locatioll IIeari~g, supra note 19. The ov-erarching goal of this hearing was to 

educate Subcommittee Members about how location-based technologies and services work, 

and how ECPA's application to location info=ation was creating a state oflegal chaos for 

Magistrate Judges, as well a, industry, privacy, and law enforcement stakeholders. In his 

opening statement at the Location Hearing, Subcommittee Chairman Jerrold Nadler 

remarked that: 

any lcgislativ-e changes to ECP A must ... sustain tlle public's confidence 

in tlle security of tlleir communications or it rcouldl harm both the robust 
79 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 123 

number of companies and civil liberties groups joined together to create the 

Digital Due Process ("DDP") Coalition in order to propose principles to 

guide congressional consideration of ECPA rcform. 21 One principle 

proposed a new standard for law enforcement access to all types of location 

information, stating that "[t]he Government should obtain a search warrant 

based on probable cause before it can track, prospectively or retrospectively, 

the location of a cell phone or other mobile conununications devlce.,,22 This 

principle seeks to treat historical and prospective location infonnation 

equally under the law and to require law enforcement to meet a probable 

cause standard before ohtaining access to any location data. 

Unfortunately for the privacy community, DDP's probable cause 

standard is a "non-starter" for law enforcement. One senior DO] otIicial 

recently told a Senate Committee tllat "if an amendment [to tlle ECPA] were 

to unduly restrict the ability of law enforcement to quickly and efficiently 

determine the general location of a terrorist, kidnapper, child predator, 

computer hacker, or other dangerous criminal, it would have a very real and 

very human cost."n The Department of Justice will indeed resist the 

imposition of a high, unitary standard for location data access and will likely 

find no shortage of allies in Congress itself to do so effectively. Even the 

market for cell phones and the rapid innovation that is ftmdamental to the 

market's health. Because ECPA inevitably involves the interaction of all 

these important anel complex considerations, we are taking the time 

through multiple hearings to educate ourselves carefully and fully before 

engaging in legislative action. 

\Ve are honored to hav-e certain witnesses here today, who are experts 

1Il these technologies. TI,ey can give us the necessary background to 

embark upon an understanding of how they work, what types of 

infomlation and records they can generate and store, and how they can be 

of assistance to law enforcement in appropriate circumstances. 

This initial educational effort is in my view not only warranted, hut 

essential before we lmdertake any effort at amending or otherwise 

reforming ECPA. After we hear the terrain described, we will move on to 

other questions today-namely, how is HCPA currently being applied to 

these location based technologies and services by the courts? 

Td at 5-6. 

21. See /lbout the Issue, DIGITAL DUE PROCESS COALITIOl' (May 5, 20lU), http://..,,,,",'W. 

digitaldueprocess.org/ index.din?ohjectid =37940370-2551-11D [i-ilJl.02000C296BA163; see aLro 

HOI1Je Judiiiary 2010 ECPA Reform Heant(g, J14pra note 18, at 12 (written statement of James X. 

Dempsey, Vice President for Pub. Policy, Ctr. for Democracy & Tech.), at'ailable at http:/ / 

j lIdiciary. hOllse.gov /hearings / pel f /Dempse yl 00505. pel f. 

22. See Our Piindples, DIGITAL DeE PROCESS COALITIOl' (May 5, 2010), http://..,,,,",'W. 

digitaldueprocess.org/index.c1in?ohjectid=99G29E40-25S1-11DF-ilE02000C296DA163. 

23. Senate Judidary 2011 EC"P A Heanng, supra note 7, at 5 (statement of James A. Baker, 

Assoc. Deputy Attorney Gen., U.S. Dep't of Justice). 
80 

124 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

DDP Coalition acknowledges that ECPA refonn must "preserve the 

'building blocks' of criminal investigations.,,24 In other words, any 

amendments to the ECPA must continue to enable an investigative system 

that allows law enforcement to compel the disclosure of various types of 

non-content information under lower legal standards at the early stages of an 

investigation. Applying these less stringent standards to non-content 

infonnation avoids the premature foreclosure of valid investigations, in dlat 

it allows agents to pursue early investigative leads and "build up" to the use 

of more intrusive tools to obtain more sensitive information protected by 

higher access standards, such as the contents of communications. 

But the difficulty with imposing a probable cause standard upon law 

enforcement access to all location data, as a matter of policy, does not 

minimize or negate dle need for Congress to examine how law enforcement 

uses location information and to assess the privacy impact of current law 

enforcement access standards for location information. That examination 

will reveal an urgent need for Congress to amend the ECPA-hoth to clarify 

the law and reestablish the balance of interests among law enforcement, 

privacy, and industry equities.25 

The unitary probable cause standard advocated by the pnvacy 

community and rejected by law enforcement has led to a stalemate. So, where 

do we find ourselves? j\s co-authors who approach ECPA reform from very 

different backgrounds and perspectives, we recogni7e the need to propose 

law enforcement standards for location information that: (1) articulate clear 

rules for courts to apply and law enforcement agents and industry to follow; 

and (2) strike a reasonable balance among the interests of law enforcement, 

24. Id; see also Hotlse 

(written statement of James 

2010 ECP/l Reform Hemin/!" supra note 18, at 16-17 

Dempsey). The DDP C:oalition recognizes that: 

Id 

[u]nder current law, govemment investigators often work their way up the 

ladder to probahle cause, starting with subpoenas for suhscriher 

identifying information and stored transactional data, then moving to 

court orders under 2703(d) for more detailed transactional data and court 

orders, based on less than probable cause, for real-time interception of 

signaling and routing information. Based on analysis of this and other 

data, they may have prohahle cause to ohtain a search warrant. 

25. E,,-en the Department of Justice "applaud[s] [Senate Judiciary C:ommittee] efforts 

to lmdertake a renewed eXanllnahon of whether [ECPA's] current statutory 

scheme ... adequately protects privacy while at the same time fostel~ng innovation and 

economic development." See Senate judid(J"ry 2011 RCPA Heming, J'upm note 7, at 6 (testimony 

of James A. Baker). Mr. Baker further notes that "liJt is legitimate to have a discussion about 

our present conceptions of privacy, ahout judicially-supervised tools the govemment needs 

to conduct vital law enforcement and national security investigations, and how our statutes 

should accommodate both." Id 
81 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 125 

privacy, and industry such that they could be included in legislation that 

might be passed by Congress. Articulating such a reasonable proposal 

requires knowledge of technology, law, policy, and politics. 

For the purpose of offering a reasonable legislative proposal, we assume 

as an incontestable value that law enforcement should have access to location 

infonnation that is necessary and suHicient to ensure the safety of the public 

by apprehending criminal perpetrators and disrupting future criminal 

activity-but no more. \Ve also assume as a second and equally 

uncontestable value that people should be, and know they are, free from any 

government scrutiny of their location data that is not necessary to that public 

safety tlJ11ction. Neither of these values is an absolute one. As such, our 

proposal is neither the most "privacy protective" standard possible, nor the 

most "law enforcement friendly" standard imaginable. Indeed, what we offer 

in Part VI is the product of a dialogue between the authors: one a committed 

privacy advocate and technologist, the other a former federal prosecutor who 

has both used location tools in that role and considered them from a 

legislative perspective while working for the TTouse Judiciary Committee. 

We believe this Article will advance the debate by proposing a policy 

framework, including model access standards that will be palatable to all 

stakeholders insofar as each of their positions will be improved in some 

appreciable way. Part II of this iv-ticle provides a brief background 

discussion of various current location technologies and the level of location 

precision they offer. Part III explores the confusion currently plaguing courts 

over law enforcement access standards to location data and examines what 

those standards require the government to show. Part IV discusses some 

"lessons learned" from congressional hearings and advocacy efforts during 

the 111 th Congress, specifically informed by Stephanie's work on the House 

Judiciary FCP /\ reform hearings. Part V examines how courts considering 

law enforcement access to global positioning system ("GPS") location 

infonnation have articulated privacy impacts and other social harms using the 

interpretive frames of Orwell's dystopia in 1984, as well as what has come to 

be called the "panoptic effect" -the atLxious response produced by the 

presumed omnipresence of the government's gaze. Part V ultimately suggests 

that location privacy is best addressed by the legislative branch. Finally, Part 

V 1 presents a model legislative privacy framework for location information, 

including law enforcement access standards and other types of 

"downstream" privacy protections to ensure that, among other things, law 

enforcement agencies do not retain location data longer than needed for 

legitimate law enforcement purposes. 
82 

126 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

II. TECHNOLOGY 

Over the past few decades, the mobile phone has evolved from a luxury 

status symbol to a necessity. By the end of 2010, more than ninety-five 

percent of the U.S. population subscribed to a mobile telephone service.26 As 

consumers have embraced cellular phones, law enforcement agencies have 

gained access to several methods through which to obtain both historical and 

real-time (prospective) location information. Generally speaking, this 

information can be separated into hvo categories: passive collection of 

information incident to the delivery of cellular services, and active 

surveillance in which infonnation is collected and processed solely to benefit 

law enforcement agencies. In addition to this distinction, there are several 

different technologies that can be used to obtain location infonnationsome highly accurate, others much less so, hut with the general direction of 

innovation tending towards greater precision. The purpose of this Part is to 

provide the reader with a brief introduction to each of these technologies and 

the ways in which they can be used to determine or track the location of 

individuals. 

A. ABRlEF IN'l'RODUCno'\l'l'O CELL PHO'\lETECH'\IOLOC;Y 

Unlike conventional "wireline" phones, mobile phones use radio to 

communicate between the customer's telephone and the carrier's network. 

Service providers maintain large numbers of radio base stations (also called 

"cell sites") spread throughout their geographic coverage areas. 27 These cell 

sites are generally located on "cell towers" serving geographic areas of 

varying sizes, depending upon topography and population concentration. 

Service providers are deploying higher-capacity network architectures, with 

the potential to provide more precise information regarding a phone user's 

location. 

As part of their normal function, mobile phones periodically identify 

themselves to the nearest cell site as they move about the coverage area.28 

26. W'imess Quick F actJ~ C l'lA-WIRELESS ASS'N (2011), http:/ / www.ctia.org/ advocacy / 

research/index.cfm / aid/! 0323. 

27. Press Release, Informa Telecoms & Media, The Shape of Mobile 'ktworks Starts 

To (;hange as Pemtocells Outnumher Macrocells In US (Oct. 21, 2(10), http://femtoforum. 

org/fema/pressreleases.php?id=269 (,,[FJemtocells now outmunber conventional outdoor 

cell sites in the United States marking a major milestone in the evolution of mobile 

networks. Conservative estimates suggest there are currently 350,000 femtocells and around 

256,000 macro cells in the US. Furthe1more by March 2011, there are expected to be at least 

twice as many femtocells as macrocells in the US."). 

28. Locatioll Hearillg, supra note 19, at 13 (testimony of Prof. Matt Blaze, Univ. of Pa.) 

("Cell phones, as they move and as they are turned on, discover the base station with the 
83 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 127 

This enables wireless carriers to know how to reach a particular subscriber's 

phone when it receives a call. Of course, mobile telephones (as their name 

suggests) are portable, and so when a phone moves away from the eell site 

\vith which it started a call and nearer to a different cell site, the call is 

"handed over" from one cell site to another without intermption.29 

Each cell site has a large but fixed ma.ximum capacity that can transmit a 

limited number of concurrent calls and data streams. In an area with a low 

number of users (or users who make few ealls and who are not heavy users 

of data services), only a few cell sites will he necessary, and each can serve a 

large geographical area. Tn areas with large numbers of active users, however, 

and particularly those who make heavy use of data services, a carrier will 

need to place far more cell sites, each serving a smaller geographic area, to 

compensate for d1e relatively larger usage burden placed on the local 

network.3D Carriers that do not or cannot deploy more cell sites to cope with 

increased demand suffer from slow data speeds and frequent dropped calls.31 

As such, rural areas tend to have fewer cell sites, each with greater service 

areas, than urban areas, which generally have far more sites that are spaced 

closer together. Obviously, the proximity of one cell site to another in a 

geographic area is one factor in the production of more accurate location data. 

strongest radio signal and perform a registration proces s identifying themselves, establishing 

that the user has a valid cell phone service, and identifying the local hase station that is hes t 

equipped to process the call by virtue of the strength of its radio signal."); Jee alJo id. at 20 

(written statement of Prof. Matt Blaze). 

29. Til See genemlfy Nishith D. Tripathi, Jeffrey H. Reed & Hugh F VanI,andingham, 

Hando/lin Celll/lar Systems, IEEE PIeRS. COMM., Dec. 1998, at 26, available at http://www.scss. 

tcd.ie/Hitesh.Tewari/ papers / tripathi98.pdf. 

30. Location Hearing, supra note 19, at 15 (testimony of Prof. Matt Blaze) ("[T]oday the 

limiting factor in how far apart [cell sites] can he is the numher of customers they have to 

serve. j\nd as this technology has exploded. the HlImher of clIstomers in any given area has 

gone explosively up, particularly in urban and densely populated areas."). 

3"1. For example, one carner has a reputation for dropped calls in some urhan areas like 

San Francisco, due to the presence of large numbers of tech-savvy users with data-hungry 

iPhones, comhined with the three-year waiting time required hy the local authorities to get 

permission to erect new cell towers (which is often combined with further local 

obstmctiorusm, whether motivated by opportunistic financial holdups or by 'dMBY 

reactions to cell tower constmction from individuals and communities with valuable real 

estate holdings). See Edward Wyatt, /lTci.cT and T-Mobile CiJie/s Field Skeptical Questions on 

C:apitol IIill, "l.Y. TIMES (May 11, 2(11), http://www.nyitines.com/2011/0S/ I2/technology/ 

12phone.html ("T-Mobile ads made merciless fun of AT&T's reputation for dropped calls 

and sluggish wireless data connections"); MG Siegler, Stel'e Jobs Continues To Answer the 

Questiom That ATc7T Won't, TEC:HC:RlJ'lC:H Only 18, 2010), http://techcrtlnch.com/2010/ 

07/18/steve-jobs-att-2/ ("[Apple CEO Steve .JobsJ said that it takes lAT&TJ three years to 

get approval for a new cell tower til San Francisco. Yes, three years. 'That'.r the .ringle bigge.rt 

pmblem hm,zng,' Jobs said .... Jobs also noted at the press conference that it takes 'abo!!t 

three to add a new cell tower in Texas."). 
84 

128 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

13. CELL SITE n\.TA 

Wireless service providers retain detailed logs for diagnostic, billing, and 

other purposes. These logs reveal the calls and Internet connections made 

and received by wireless subscribers, as well as detailed technical infonnation 

regarding the ~ell sites that were used.32 Such logs generally only reveal which 

particular cell site a phone was near at the time of the call. 

Data from multiple towers can be combined to pinpoint (or 

"triangulate") a phone's latitude and longitude with a high degree of accuracy 

(typically under fifty meters).33 This triangulated cell site data is generally only 

available prospectively, either due to a 911 call by a subscriber, or because a 

law enforcement agency has asked a carrier to collect it. Some carriers do 

routinely track and record triangulated data, and movement toward this 

practice is a general trend in the industry, although it is not yet the dominant 

practice, much less the common policy of all companies. 34 A.s such, law 

enforcement agencies can also obtain high-accuracy, triangulated historical 

data when it is available due to a specific company's data collection practices. 

C. GLOBAL PCJSI'nONL\IL~ SYSTEM ("GPS") 

Many mobile phones now include special hardware that enables the 

device to receive signals from a constellation of glohal position satellites.'s 

Software on the phone can use these signals to calculate latitude and longitude, 

32. McCullagh, supra note 2 ("Cellular providers tend not to retain moment-bymoment logs of when each mohile device contacts the tower, in part hecause there's no 

business reason to store the data, and in part because the storage costs would be prohibitive. 

They do, however, keep records of what tower is in use when a call is initiated or 

answered ... . 'j; see also COMPUTER CRIME & INTELLECTUAL PROP. SECTION, DEP'T OF 

JUSTICE, RETENTION PERIODS or MAJOR CELLULAR SERVICE PROVIDERS (2010), available at 

http:/ /www.wired.com/images_blogs/threatlevel/2011 /09/reten tionpolicy.pd f Qisting, in 

chart f01m, data retention periods by the major cellphone carriers). 

33. This requires the placement of special radio equipment at each cell site. See generally 

iJJcafion Hearing, supra note 19, at 38-41 (statement of Michael Amarosa, Sr. Vice President 

for Public Affairs, TmePosition tnc.). 

34. T LJcatioll Hearing, .wpm note 19, at 26-27 (written statement of Prof. Matt Blaze) 

("(Whether locations arc routinely tracked and recorded at times other than when calls arc 

made or received depends on the policy of the particular carrier.) ... Some carriers also store 

frelluently updated, highly precise, location info1mation not Just when calls are made or 

received, but about ever-y device as it moves about tl1e networks. Maintaining such detailed 

records ahout the locations of phones as they move from place to place makes good 

engineering sense, and we should expect this trend to continue as part of the natural 

progression of technology."). 

35. This comnllmication is one-way. Phones receive signals from the satellites but do 

not transmit anything back to them. 
85 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 129 

often with a high degree of accuracy (less than twenty-five meters).36 

Although GPS is often more accurate than any other location technology, 

there arc a few limitations: GPS signals arc weak, high-frequency signals that 

do not penetrate walls, and as a result CPS often does not work when 

indoors. 'vforeover, for the same reason, GPS often does not function well in 

"urban canyons" due to signal deflection off of the sides of tall buildings. 

Furthermore, the GPS functionality tends to use significant amounts of 

power, which can lead to shorter battery life.37 \v11en GPS functionality is 

available, wireless carriers can prospectively obtain a device's location, such 

as when the user dials 91 L or when asked to do so hy law enforcement 

agencies. Carriers do not generally have historical GPS data to deliver. 

Many smartphones now provide access to the GPS functionality to thirdparty "apps" installed on the devices. As such, app developers and location 

service providers also have access to users' GPS location data, often far more 

than the wireless carriers, although this is usually with the user's knowledge 

and consent.,g Law enforcement agencies can compel these location service 

providers to disclose the historical GPS data in their possession, although 

prospective disclosures are limited to user-initiated "check-ins," as these 

companies are usually not able to generate their own GPS queries. 

D. \\!lFl 

Many smartphones include wireless internet ("Wi Fi") functionality, 

enahling device owners to hrowse the weh at much faster speeds (and 

without impacting their carrier-imposed data cap) when at home, work, or in 

many public places. In addition to providing a connection to the Internet, the 

\ViFi connections can also be used to determine the approximate location of 

the device. 

36. iJJcafion Hearing, JUpm note 19, at 55 (attachment to written statement of'vl1chael 

Amarosa). 

37. Letter from i\nc1y Lees, Presic1ent, Mobile Commc'ns TIus., Microsoft CO!})., to 

Rep. Fred Upton et al. (May 9, 2011), available at http://blogs.technet.com/cfs-file.ashx/ _key/ 

communityserver-hlogs-components-wehlogfiles/OO-OO-OO-il2-9S/24S1.Comumer-Privacy-

_2600_-Windows-Phone-7 -_ 2DOO_Submission-to-House-Energy-and-Commerce-Committee-

_2DOO_-5.9.2011.pdf ("Windows Phone 7 generally relies upon WiFi access point or cell 

tOVNer infonnation to c1etemline a phone's approximate location because GPS location data 

is not always available, and when it is, it can draw more heavily on battery power .... "). 

'Ill. If a user "dlecks in" with a location provider like Foursquare, that location 

provider willleam their location, but the wireless carrier will not, as the infotmation is sent 

directly to the location provider. 
86 

130 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

Several companies have created databases listing wireless networks and 

their approximate geographic locatioIl.39 Initially, these databases were 

populated with data obtained by driving through the streets of eities around 

the world, collecting the data with a laptop or other special hardware.4o In 

recent years, however, Google, !\pple, and Microsoft have all enlisted the 

"crowdsourced" assistance of millions of smartphones to collect this data for 

them. 41 

By determining the available WiFi networks and submitting this list to 

one of the datahase providers, applications on the device and the platform 

mobile vendor (e.g., Google, I\pple) can quickly determine the user's 

approximate location without using GPS, which would consume signitlcantly 

more battery power.42 Location data is increasingly valuable, enough so that 

the major platfonn vendors have been "willing to push the envelope on 

pnvacy to collect it."13 Not only is location data used for maps and 

39. See Greg Stirling, Google nfldr Street Vieui WzFi Datd Collectiotl, Mig Now Need Other 

SOllrcesfor Location, SEARCII ENGINE LA'ID (Oct. 20, 2010), http://searchengincland.com/ 

gpogle-end,-street-view-wifi-data-collection-potentially-needs-other-,ources-for-Iocation-S3373 

("One of the purposes of collecting WiFi locations is to enable Google to identify user 

location (on handsets, laptops and pes to some degree) through triangulation using a 

database of hotspots."); see diro FI~quetltiy Asked Questiotls, SKYHOOK \VTREf.ESS, 

http:/ ;"vww.skyhookwircless.com/howitworks/faq.php (last visited Mar. 17,2012) ("Skyhook 

deploys vehicle-ha,ed ,ignal ,canning and data collection technologies, a common practice in 

the digital mapping and data collection industries. These Skyhook-equipped vehicles conduct 

systematic and comprehensive signal sU1"Veys by traveling every public road and highway in 

targeted coverage areas. ll1ese sigilal surveys capture the data output of individual access 

points and pair them with a date, time, and location stamp at the point where they are 

received hy the data collection device."). 

40. See Brad Stone, Google SayJ It Collected Plivate Data I:ry .Mistake, N.Y. TIMES (May 

14, 2010), http://www.nytimes.com/201O/05/15/bmine>>/lSgoogle.html(..[B]ecause of a 

programming error in 2006, the company had ... been mistakenly collecting snippets of data 

that happened to be transmitted over non-password protected wi-fi networks that the 

Google camera cars were passing."); see also Jenna Wortham, Cellphone Locdtor SYJtem 0:eedr No 

Satellite, N.Y. TIMES (May 31, 2009), available at http://www.nytimes.com/2009/06/01/ 

technology/start-ups/Ollocate.html (explain..ing how the company Skyhook "uses the chaotic 

patchwork of the world's wi-fi networks, as well as cell towers, as the basis for a location 

lookup sel"Vice"). 

41. Julia Angwin & Jennifer Valentino-Devries, Apple, Google Collect User Data, WALL 

ST. J (Apr. 22, 2011), http://on.wsj.com/zp2Euo(''Apple Inc.'s iPhones and Google Inc.'s 

.I\ndroid smartphones regularly transmit their locatiOn> hack to Apple and Google, 

respectively as part of their race to build massive databases capable of pinpointing 

people's locations via their cell phones."). 

42. See gemmliy John \{orris, Apple TmdeJ Przl;acy for Battery T ije, Tm/ead if Protecting Botb, 

CENTER rOR DEMOCRACY & TECH. (Apr. 22, 2011), https:/ /www.cdt.org/blogs/johnmorris / apple-trades-privacy-hattery-life-im tead-pro tec ting-ho tho 

43. Miguel Hclft, ./Jpp!e and Google UJe Pbone Dattl To Alap tbe World, ~.Y. TIMES (Apr. 

25,2(11), https:/ /www.nytimes.com/2011/04/26/technology/2610cate.html. 
87 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 131 

navigation services on mobile devices, but it is also used to customize 

advertising aimed at people in a particular place. Such ads are far more 

lucrative than other ads and are becoming a major portion of the mobile 

advertising market, which industry experts estimate will be a $2.5 billion 

market by 2015.44 '\Jot only do these economic factors encourage companies 

to collect more location data, but they also encourage the collection of data 

with greater accuracy, allowing merchants to pitch advertisements to 

consumers walking past their store, rather than just those in the neighborhood. 

1i. PINGS 

Most of the location information described in this Part is collected in the 

process of providing wireless voice and data services, or due to users calling 

911 or using a location-enabled app on their smartphones. For such 

infonnation, law enforcement agencies can either request historical data 

already stored by the provider, or request prospective surveillance that will 

provide data to the law enforcement agency as soon as the carrier receives it. 

In either case, the information collection is passive, in that no new data is 

generated due to the law enforcement surveillance request. 

It is also possible, however, for carriers to monitor their customers 

actively, generating new data specifically in response to a request from law 

enforcement agencies. In such scenarios, the wireless carriers can covertly 

"ping" a subscriber's phone in order to locate them when a call is not being 

made. Such pings can merely reveal the nearest cell site to the suhscriher,45 or 

more accurate GPS or triangulated data if requested. 46 Tn addition to the 

44. Id 

45. See Stone v. State, 941 A.2d 123S, 1244 (Md. O. Spec. App. 200S) ("Trooper 

Bachtell obtained the appellant's cell phone number ,mel contacted his cell phone service 

provider. At Trooper Bachtell's request, the service provider conducted a 'ping' of the 

appellant's cell phone, which revealed that the phone was 'within a two mile radius of the 

Frcdcrick County Dctcntion Centcr.' "). 

46. See Comments of CTIA-The \Vireless Association on U.S. Department of Justice 

Petition for Expedited Rulemaking at 17, In n: Petition for Expedited Rulemaking To 

Establish Technical Requirements and Standards Pursuant to Section 107(b) of the 

Communications .I\ssistance for Law Fnforcemenet ,I\ct, Docket Ko. RM-'1137G (Fed. 

Commc'ns Comm'nJuly 25, 2007), available at http://~alltoss.tcc.gov/ cds/ commcnt/vicw?id= 

5514711157 ("Law enforcement routinely now requests carriers to continuously 'ping' 

wireless devices of suspects to locate them when a call is not being made so law 

enforcement can triangulate the precise location of a device and [seek] the location of all 

associates communicating ",ith a target."); Jee (jim Devega v. State, 689 S.F.2d 293, 299 (Ga. 

20lU) C"l'l'Jhe investigators requested that Devega's cell phone provider 'ping' his phone, 

which the officers descrihed as sending a signal to the phone to locate it by its glohal 

positioning system (GPS). The company complicd and informed the police that the phone 

was moving north on Cobb Parkway."). 
88 

132 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

carrier-initiated pings, law enforcement agencies have also perfonned "low 

tech" pings by calling a target and hanging up before the phone rang, in 

order to generate cdl site data that could then be requested from the carriers.47 

F. TRENDS 

The increasing accuracy and use of location data is motivated by the 

proliferation and advancement of mobile technology, as well as the lucrative 

commercial market for location-based services and marketing. \Vithin that 

general context, there are several trends worth noting that suggest that single 

cell site data will become increasingly accurate. This postulation is particularly 

significant for evaluating current DO] policies governing the legal standards 

for law enforcement's compelled disclosures of prospective location 

information.48 

First, in an attempt to "fill the gaps" in their coverage, wireless carriers 

have, in the past few years, distributed hundreds of thousands of 

"microcells," "picocells," and "femtocells" to customers, which connect to 

the user's hroadhand internet connection and provide cellular connectivity to 

phones within tens or hundreds of meters. Tndustry estimates indicate that 

there are already more than 350,000 femtocells deployed in the United States, 

as compared to the more than 250,000 traditional carrier cell sites.49 As these 

devices often broadcast a signal no further than a subscriber's home, the 

accuracy of single cell site location data can in some cases be more accurate 

than CPS, depending on whether the target is connected to a traditional cell 

site, or a residential femtocel1. 

Second, the success of Apple's iPhone and other smartphones has led to 

a massive increase in the use of data by mobile users. For example, AT&T 

has seen an 8,000 percent increase in data traffic between 2007 and 2010.50 In 

response to this increased demand on their networks, carriers are deploying 

new cell sites and reducing the coverage area of existing towers.51 I\S carriers 

47. United States v. Porest, 355 fi.3d 942, 947 (6th Cir. 2(04) ("In order to reestahlish 

visual contact, a DEi\ agent dialed Gamer's cellular phone (without allowing it to ring) 

several times that day and used Sprint's computer data to determine which cellular 

transmission towers were being 'hit' by Gamer's phone. This 'cell site data' revealed the 

general location of Gamer."). 

48. See infra Section lILA.1. 

49. Press Release, Infonna Telecoms & Media, JUpra note 27. 

50. Dan Meyer, ATi"'T Filil~g Pml'ides Iliterestilcg II/dustry Data, RCR W1K12LESS (Apr. 

25, 2011), httF/ / www.rcrwireless.com/artic1e/20110425/C!I.RRTERS/11 0429949/ att-filingprovides-interesting-industry-data. 

51. Tracy Ford, Tower Illdu.rtry Primed for Growtl! uitl! Carrier Buildoutr, RC:R 

WIRELESS NEWS (Mar. 3, 2(10), http://www.rcrwircless.com/ARTICLE/20100303/INFRA 

STRUCTURTI/100309979/tower-industry-primed-for-growth-with-carrier-buildouts ("LTE 
89 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 133 

embrace faster 4G mobile data technologies, they will need even more cell 

sites, further reducing the coverage area around each tower. 

As the coverage area around each traditional cell tower shrinks, and 

consumers increasingly embrace femtocells in their homes and businesses, 

single cell site data will become far more accurate-in some cases as good as 

GPS, and in others pinpointing someone's location to an area the size of a 

few blocks. 

III. THE LAW 

This !\rticle proposes a policy framework that balances the interests of 

stakeholders affected by law enforcement access standards for provider-held 

location information. Defore turning to policy proposals, the Article first 

discusses how law enforcement currently justifies its collection of prospective 

and historical location data-both under the DOl's current interpretation of 

the law and the suggested policy guidance it gives to prosecutors and agents 

in the field. 

This Part describes how the DOT's and courts' various statutory 

interpretations have created a set of contlicting standards for law enforcement 

access to location data. Changes in technolos'Y, combined with the instability 

in the law created hy contlicting legal standards for location data, create a 

critical need for Congress to amend the law to produce a better balance 

among privacy, law enforcement, and industry equities-a balance that 

would ideally benefit all stakeholders in some appreciable way. As such, this 

Part seeks to identify where that balance, as a matter of policy, may lie and 

how new law enforcement access standards or other "downstream" privacy 

protections might serve that legislative end. This Part therefore focuses on the 

policy implications of the current law, not on how the Fourth Amendment 

might apply to law enforcement access to location data held by a third party. 

\Vhen and under what circumstances the flourth Amendment might require 

law enforcement to obtain a warrant to obtain location information from 

third-party providers remains a contested area of the la'.v52 and one that is 

is going to be driving revenue for the tower companies ... as a result 0 f the incredible demand 

supported by LTE 700 _\1Hz spectrum and the resulting splitting and additional coverage 

and capacity that the carriers are going to have to put in place to meet that demand. 

52. Cumpare Susan Freiwald, Cell Phune Lucation Data and [he Fourth AI71erzcim,ell£: A 

Questioll of Low, Not Fact, 70 MD. L. Iiliv. 677, 717 (2011) (arguing that courts should require 

a warrant fix access to location data in all cases because such acquisition is a search under 

the Fourth Amendment), 22.ith Orin S. Kerr, COlli1 Rules That Police Canllot Use rr'-atTants To 

Obtain {;ell Phone Locatioll of Perrall W/m Ir Subject of AmJt Warrant, VOLOKH CONSPIRACY 

(Aug. 8, 2011), http://volokh.com/2011/08/08/ court-mlcs-that-police-cannot-use-warrantsto-obtain-cell-phone-location-of-person-who-is-subject-of-arrest-warrant/ (arguing that location 
90 

134 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

beyond the scope of this Article to reconcile. To the extent that the 

discussion touches upon Fourth Amendment issues, it does so in the service 

of describing and developing a policy discussion, not to offer an opinion on 

the correct application of the Fourth i\mendment to location information. 

A. LEGAL BACKGROUND FOR REAL-TIME OR "PROSPECTIVE" 

CELL SITE DATA 

Locating dIe proper law enforcement access standard for prospective 

location data in the current law is, in some respects, like dIe quest for the 

Holy Grail, the search for the fountain of youth, or the hunt for a truly 

comfortahle pair of high heels-one is unlikely to find them. This legal 

mystery remains unsolved primarily for two reasons. First, the ECP 1\ ii_the 

primary law governing law enforcement access to wire, oral, and electronic 

communications and other stored subscriber records and infonnation-does 

not contain dIe word "location" in any part of dIe statute or otherwise 

provide language that could be easily interpreted to cover law enforcement 

access to real-time location data from third-party providers.54 Second, 

Congress, in a different statute, has only expressed what is for 

purposes of law enforcement access to prospective location information 

from a third-party provider, but not what is either neceJSary or for 

such compelled disclosures. Indeed, dIe Communications Assistance for Law 

Enforcement Act ("CALEA") merely instructs that "any infommtion that 

may disclose the physical location of [a telephone service] subscriber" may 

infonnation of phones is not protected by the Fourth Amendment under Smith v. lvIarylalld, 

442 U.S. 735 (1979». 

53. See supra note 17. 

54. ~onsider, for example, the testimony of Judge Smith descrihing the difficulty he 

amI other Magistrate Judges have faced in detennining the proper law enforcement access 

standard for real-time location infonnation: 

~Moreover, none of the other categories of electronic surveillance seemed 

to fit. The pen register standard was ruled out by a proviso in a 1994 

statute kno"~l as CALEil.. llle wiretap standard did not apply because 

CSI does not reveal the contents of a communication. The Stored 

~ommunications Act (S~A) standard did not seem to apply for two 

reasons: the definition of "electronic commlmication" specifically 

excludes information from a tracking deYice; and fbe structure of fbe SCA 

was inherently retrospective, allowing access to documents and records 

already created, as opposed to prospective real time monitoring. 

T J)((Jtion Heming, mpra note 19, at 82-83 (footnotes omitted); j~ee (JLm Kevin S. Bankston, Only 

tbe DO] KIl02JJJ: Tbe Secret Law ofElectirmic SlIrvei!iance, 41 U.S.F. L. REv. 5i:l9, 606--09 (2007) 

(analyzing how the \Viretap Act and Pen/Trap statute do not provide the requisite authority 

for such "tracking" and fbe SOl,. only aufborizes retrospective access to previously stored 

communications content and non-content information). 
91 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 135 

flat be acquired "solely pursuant to the authority for pen registers and trap 

and trace devices."ss Therefore, with respect to a compelled disclosure, if 

real-time location data cannot be provided to law enforcement "m/elY 

pttrrttafzt" to a court order for a Pen/Trap device, there must he some further 

requirement. But that requirement, unfortunately, remains undefined in the 

law. This exercise in ~Via Negati1la56 makes for great scholastic discussions 

about the incomprehensible character of an ineffable God but it is not very 

effective as a descriptive tool for disceming a legal standard. At best, it is a 

rather ineffective inversion of Justice Stewart's famous concurrence in 

jacobe!!i.r 11. Obio about the similar difficulty the Court encountered in definin8 

"hard core pornography" with any accuracy: "T know it when T [don't] see 

it. ,,57 Stated more precisely, if less concisely and memorably, "I'll know it 

when I can infer its exis tence and nature by seeing everything that it is not." 

1. Tbe DOJ's Tntelpretatiol2 of tbe Standard fir Obtaining Prospedil1e 

Cell Site Data 

Lacking clear, affirmative statutory guidance, the DOJ has routinely 

acquired, since at least 200S, certain categories of "less precise" prospective 

cell site information through the combinatiolZ58 of two court orders: (1) a 

Pen/Trap court order pursuant to 18 USc. § 3123,59 and (2) a "D" Order 

pursuant to 18 USc. § 2703(d), a section of the Stored Communications Act 

("SeA") that pennits the government to compel the production of non55. 47lJ.S.C § 1002(a)(2) (2010). 

56. The "Via Negativa" is a method of philosophical and theological argument often 

associated with mysticism, sometimes referred to as "negative" or "apophatic" theology that 

attempts to describe God or the divine good by negation, specifically in tenns of what God 

is 110t (apopbasis), discerning instead only what may not be said accurately concerning the 

goodness and perfection(s) of God, which are beyond direct expression. The technique has 

its roots in several Greek philosophical schools, as well as several Western and Eastern 

religious traditions. See Negative Theology, THE BLACKWELL DICnONARY OF WES'J'hR'l 

PHILOSOPHY 465-66 (Nicholas Bunnin & ]iyuan Yu eds., 2004); JU a/.ro K,\RE'l 

ARMSTRO'lG, THe CASE POR COD 317 (2009) (describing the potential resurgence of 

apophatic argumen tin pos tmodem theology). 

57 . .lacobcllis v. Ohio, 378 L.S. 184,197 (1964) (Stewart,J, concurring). 

58. See Bankston, supra note 54, at 609-12 (descrihing the first puhlically known case 

where the DO] articulated the "hybrid theory" in applying for a court order authorizing 

access to real-time cell site inf01'mation). 

59. 18 U.s.c. § 3123(a)(1) (directing that a court "shall enter an ex parte order 

authorizing the installation and use of a pen register or trap and trace device ... if the court 

finds that the attomey for the Government [in an application pursuant to 18 U,S,C 

§ 3122(a)(1)] has certified to the court that the information likely to be obtained IS 

relevant to an ongoing criminal investigation"). 
92 

136 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

content records or information pertaining to a subscriber or customer.60 

\\"hen combined, these two orders are known as a "hybrid order.,,61 A DO] 

manual documents that the rationale behind the DOl's "hybrid" use of these 

two statutes derives from a comhination of discrete statutory requisites.62 

First, because "cell-site data is 'dialing, routing, addressing or signaling 

information,' ... 18 U.s.c. § 3121(a) requires the government to obtain a 

Pen/Trap order to acquire this type of infonnation."63 Second, however, 

because CALEA "precludes the government from relying 'solely' on the 

authority of the Pen/Trap statute to obtain cell-site data for a cell phone ... 

some additional authority is required to ohtain prospective cell-site 

information."M The DO] asserts that "[s Jection 2703(d) provides this 

authority because ... it authori7es the government to use a court order to 

obtain all non-content information pertaining to a customer or subscriber of 

an electronic communications service [or a remote computing service].,,65 

The same DO] manual, puhlished in its third edition in 2009, also 

provides guidance ahout the "precision" of the information likely to he 

obtained from cell site data (exclusive of GPS location technologies). The 

manual instmcts that "rclell-site data identities the antenna tower and, in 

some cases, the 120-degree face of the tower to which a cell phone is 

connected, both at the beginning and the end of each call made or received 

by a cell phone.,,66 The manual further explains that "[tJhe towers can be up 

to 10 or more miles apart in mral areas and may he up to a half-mile or more 

60. See id. § 2703(c) (authorizing law enforcement to compel "a provider of electronic 

communications service or remote computing sen-tce to disclose a record or other 

information pertaining to a subscriber to or customer of such service (not including the 

contents of communications) only when the gov-ernment entity ... ohtains a court order for 

disclosure under subsection (d) of this section ... "). 

61. U.S. DICP'T or .IUSTICE (DOl), SIl'\RCHI'fG Al'D SEIZING CO',]PUTERS AND 

ORTAT1'T'lG FT.ErTR01'TC: FVTDE1'rE T1' CRTMT1'AT. INVESTTGATTONS 160 (3d ed. 20(9) 

[hereinafter DOT MANUAL], available at http://www.justice.gov/criminal/cybercrime/docs/ 

ssmanual2009.pdf. 

62. Id at 159-60. Some published decisions also indicate that DO] prosecutors have, at 

times, offered the All Writs Act, ch. 646, Ij 1651,62 Stat. 869,944 (codified as amended at 28 

USc. § 1651 (2010», as a "mechanism for the judiciary to give [the government] the 

investigative tools that Congress has not." In I? Application of the U.S. for an Order 

Authorizing the lise of a Pen Register and a Trap and Trace Device (In re ED.N.Y. 

Application), 396 F. Supp. 2d 294, 325 (ED.K.Y 2(05); Jee alJa In re Application of the U.s. for 

an Order Authorizing the Installation and Use of a Pen Register (Inl~ n7D.N. Y. Application), 

415 F. Supp. 2d 211, 219 (\VD. N.Y 2006). 11,ese courts did not endorse this theory. 

63. DOl MANUAL, Jtlpranote 61, at 159-6U. 

64. Id at 160. 

65. Id 

66. Id at 159. 
93 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 137 

apart even in urban areas.,,67 Relying on this description of cell tower 

technology, the manual concludes: "[A]t best, these data reveal the 

neighborhood in which a cell phone user is located at the time a call starts 

and at the time it terminates; it does not provide continuous tracking and is 

not a virtual map of a cell phone user's movements."6R 

This description of the relative precision of cell site data, even if it is 

intended only to apply to single cell tower data (i.e., no multi-tower, 

triangulation, or GPS location information), will soon be-if it is not 

already-outdated with the deployment of microcell, picocell, and femtocell 

technology that, in some cases, can be more accurate than GPS.m Indeed, in 

urban areas and other environments where microcell technology is present, a 

cell phone's location can be identitled on an individual Hoor or room within 

a building.70 Moreover, the precision of single cell tower data will only 

increase as providers deploy new cell sites to cope with the surge in mobile 

user data traffic.'! 

The DOJ manual further advises prosecutors that in most districts they may 

obtain prospective cell site information with the use of hybrid orders, but it 

also acknowledges that some magistrate judges require a "probable cause" 

showing before authori:oing law enforcement access to any type of 

prospective cell site data.72 This split among magistrate judges, characterized by 

one federal prosecutor as the "Santa Ana Judicial Revolt,"" is discussed next. 

2. fudirial ReJis/ance to the Governmentj· UJ'e of liyblid Ordm' 

A growing number of magistrate judges within and across various judicial 

districts have rejected the government's use of the hybrid theory to obtain 

any type of prospective cell site information.'"! Some courts have held that, as 

67. Id. (citing III 11! Application of the United States of America for an Order for 

Disclosure of Teleco111111. Records and i\uthori7.ing the Use of a Pen Register and Trap and 

Trace (In re S.D.N.Y /lpplicatioll), 405 F. Supp. 2d 435, 449 (SDN.Y. 2005)). 

6S. Id. 

69. See Locatioll Hearillg, J"lijJm note 19, at 25 (written statement of Prof. Matt Blaze, 

Univ. of Pa.). 

70. Td. 

71. Id. 

72. DOJ MANUAL, .,rijJra note 61, at 159-60. 

73. E-mail from Tracy Wilkison reo Changes to GPS / Cell Site for Investigations 

Form (July 28, 2008) (informing other prosecutors about changes in office procedures for 

obtaining GPS and cell site information), ill U.S. Dep't of Justice, Response to Freedom of 

Info=ation _Act Request No. U7-4123 reo Mobile Phone Tracking 13 (Sept. 8, 2UU8), avmlable 

at http://'N'Ww.adu.org/ pdf.s / free speech/ cellfoia_release_07 4123_200S0911.pdf 

74. Location Hearing, supra note 19, at 81-85, 93-94 (testimony of Judge Stephen 

Wm. Smith, U.S. Magistrate Judge). PlOD. R. CR1M. P. 41(d)(I) directs that "after receiving an 
94 

138 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

a matter of statutory construction, the Pen/Trap order and the D Order 

cannot be used to obtain prospective cell site infonnation, but that Rule 41 

provides the necessary authority because "it governs any matter in which the 

government seeks judicial authorization to engage in certain investigative 

activities.,,7s More specifically, some of these courts have found that 

compelled disclosure of prospective cell site data is more akin to a tracking 

device placed under a vehicle, as defined in 18 USc. § 3117,76 than to the 

combination of elements comprising the govemment's hybrid theory and, 

therefore, would prompt the prudent prosecutor to obtain a Rule 41 

\varran t. 77 

Even the magistrate and district judges that have accepted hybrid orders 

and issued published decisions on the question have restricted law 

enforcement access to limited cell site information "yielding only generalized 

location data.,,78 Magistrate Judge Gorenstein from the Southern District of 

::--.J e\V York, in what may he the "most cogent expression,,79 hy a court in 

accepting the government's hyhrid theory, specifically noted: 

[The government's request pertained to cell site information] tied 

only to telephone calls actually made or received hy the telephone 

user ... [with] no data provided as to the location of the cell phone 

when no call is in progress. [l\nd], at any given moment, data is 

provided only as to a single cell tower with which the cell phone is 

communicating. Thus, no data is provided that could he 

"triangulated" to permit the precise location of the cell phone user.80 

affidavit or other information," a Judge "must issue the warrant if there is probable cause to 

search for and seize a person or property or to ins tall and use a tracking device." 

75. In re ED.N.Y /lppfication, 396 F. Supp. 2d 294, 322 (EDS.Y 2005); see also In re 

WD.N.Y. Application, 415 fl. Supp. 2d 211, 219 (WD.N.Y 2(05) ("[T]he challenge here is to 

the Jtatutory justification for ... [the govemment's] application .... The Court does not agree 

with the govemment that it should impute to Congress the intent to 'converge' the 

provisions of the Pen Statute, the SCA, and CALHA to create a vehicle for disclosure of 

prospective cell information on a real time basis on less than probable cause."). 

76. "As used in this section, the tenn 'tracking device' means an electronic or 

mechanical device which permits the tracking of the movement of a person or object." 18 

U.s.c. § 3117(b) (2010). 

77. Tn re Application for Pen Register and Trap/Trace Device with Cell Site Location 

Authority (It I rr 2005 SD. Tex. /lpplication), 3% F. Supp. 2d 747, 753-64 (S.D. Tex. 2(05); In 

re ED.NY Application, 396 fl. Supp. 2d at 322. 

78. iJJcafion Hearing, Jllpm note 19, at 93-94 (Exhibit B to written statement of Judge 

Stephen Wm. Smith) (collecting Magistrate and District Court published decisions where 

courts have accepted hybrid orders for limited cell site data pertaining to single cell tOINer 

and call-related inf01mation). 

79. Id at 83. 

80. In re S.D.N.Y /lppbiation, 405 F. Supp. 2d 435, 437-48 (SDN.Y 2005). Judge 

Gorenstein notes differences between the instant case and three published decisions denying 
95 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 139 

Judge Gorenstein further explained that his analysis for the instant Order 

was based on the "technology that is available to the Government in the 

District," recognizing that, with respect to future cases, "01.e could not] know 

how ... technology may change."sl 

For Judge Gorenstein, then, the current capacity of the cell tower 

network in question (the court even looked at a map of the location of 

various cell towers in lower :Manhattan-an area it described as "densely 

populated by cell towers")82 was a factor in authorizing law enforcement 

access to the cell site data with a hyhrid order.83 If that network's capahilities 

were to change due to an evolution in technology that yielded more precise 

location information, the court might nIle differently in future cases. Indeed, 

the court's order might be as ephemeral as the capacities of the specific 

network the opinion seeks to comprehend at a specitlc moment in time. Any 

upgrade to that network that would enhance tlle accuracy of its geolocation 

capahilities in the district, made any time after the signing of the opinion, tied 

as it is to the facts descrihing the network's capacities, could render that 

opinion legally moot. 

3. Divergent Interpretations of the Standanifor Requiring Disclosure of 

Pmrpective Cell Site Data Create Legal UJlc'ertain(y 

\vllen seeking to compel "more precise" prospective location data 

generated by CPS or similar technologies, the DOl's policy is to obtain a 

warrant hased on prohahle cause. S4 \Vllile privacy advocates might view this 

as a small concession by the government, it is at best a transient one, since a 

policy decision by the DOJ is by no means a permanent or legally binding 

government access to cell site inforrnation with a hybrid order insofar as "[tJhese cases 

appear to involve requests for cell site information that go beyond both what has been 

sought in this case and what has actually been received by the Government pursuant to any 

cell site application in this District." Id. (citing In re 2005 S.D. Te:\·. /Jpplicatiotl, 396 F. Supp. 

2d 747; In t1! ED.N.Y. Application, 396 fl. Supp. 2d 294; In re Application of the U.S. fur an 

Order Authorizing the Installation and Use of a Pen Register and Caller Identification Sys. 

on TeL Numbers ISealedl, 402 F. Supp. 2d 597 (D. .\1d. 2005». 

8\. Ttl rr S. J) N. Y Application, 405 F Supp. 2d at 450. 

82. Id. at 437. 

S3. See airo In n Application of U.S. for an Order, 411 fi. Supp. 2d 67S, 6S0-S2 (\V.D. 

La. 2006) (granting an application for cell site information consistent with Judge Gorenstein's 

reasoning and scope of production of cell site information, recognizing that Judge 

Gorenstein "limit[edJ his opinion to the particular application before him" and 

characterizing the single cell site technology of that time as "not permitltingJ detailed 

tracking of a cell phone user within any residence or huilding"). 

84. Senate Judiciary 2011 EC]J/l Hearing, supra note 7, at 7 (testimony of James A. Baker, 

Assoc. Deputy Attorney Gen., U.S. Dep't of Justice). 
96 

140 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

decision. s5 To the extent that this policy decision protects privacy, it can be 

so unstable as to be subject to changes in leadership at various levels, even 

within a single administration, whose individual decisions implement the 

enforcement and oversight of a particular policy across various field offices. R6 

More troubling from a systemic perspective, however, is the inconsistent 

legal landscape that contlicting magistrate and district court decisions create 

across the country, sometimes even within the same district. s7 The system 

neither serves law enforcement needs nor protects privacy interests when 

legal standards are so uncertain. Moreover, as Judge Gorenstein's opinion 

illustrates, such uncertainty is magnified into legal instability, potentially to 

the point of unreliability, when a court's analysis is so tied to the state of 

85. A DO.) policy decision, such as a policy requiring a warrant for law enforcement to 

acquire GPS-generated location data, has no hinding authority on state or local law 

enforcement practices, and state investigators do not always follow Do.J policies. For 

example, in j)ev~ga v. State, investigators, without a warrant, requested a defendant's cell 

phone provider to "ping" his phone, which involved sending a signal to locate it through 

GPS information. 689 S.E.2d 293, 299 (Ga. 2UIU). 

S6. ~onsider, for example, Magistrate Judge Feldman's exchange with an Assistant 

United States Attorney ("ACSA'') at oral argument See Itl IT 1f"D.N.Y /1pplicatiotl, 415 F. 

Supp. 2d 211, 218 (WD.N.Y. 2006). Wl1ile the government was only seeking "general 

[prospective cell site] location infonnation" in the instmlt case, the AUSA conceded that in 

previous "hvbrid" applications, the government had sought "prospective cell site data that 

could be used by law enforcement to triangulate the location of a cell phone to a degree 

perhaps beyond 'general location information.' " Id. The court pressed government counsel 

regarding whether the position that a hyhrid order was appropriate for anything other than 

"general location infonnation" had been abandoned. TIle AUSA responded: 

\Vell there's a couple of practical things going on. One, we're before 

magistrate judges that are the gatekeepers-we're trying to convince them 

that the government isn't being some ruthless, overbem~ng entity-we're 

trying to be reasonable. So, therefore, if we can get the magistrate's ear 

and we don't have to fight this fight a zillion times, we'll back off. If you 

have this internal radar that's going "priv-acy interest, priv-acy interest", 

okay we'll back off. But is it possible the argument could be made that we 

could be here on another dav having gotten to floor one and now we're 

trying to get to floor two? Yes. Has that been suggested by anyone? 

Absolutely not 

Td. at 218 n.5; .ree airo Freiwald, .rllpmnote 52, at 717 (discussing one U.S. Attorney's o.ffice's 

failure to comply with DO.l policv advising agents to establish probable cause when seeking 

location data indicating a target's latitude and longitude (using either GPS or similarly precise 

data». 

87. See Locatiotl Heatilig, s:rpm note 19, at 83-85, 93-94 (wl~tten statement of Judge 

Stephen W1l1. Smith and Exhihit B thereto). Comp(jr~ Ttl IE an i\pplication of the U.S. fi:>r an 

o.rder for Prospective Cell Site Location Info. on a Certain Cellular Tel., No. U6 CRlM. 

MISe 01, 2006 \X'L 46S300 (SD.N.Y. 20(6) (denying application for limited single tower 

data), lJ,ztb In I~ SD.N. Y. /lpplicatiofl, 405 F. Supp. 2d 435 (grm1ting application for limited 

single tower data). 
97 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 141 

technology in a particular district at a particular moment in time that it hinges 

upon a court's own examination of a netvvork map of cell towers in a 

particular district-which would now include micro cells, picocells, and 

femtocells-comhined with expert opinion on the accuracy of location data 

that network could produce. RR The court analp:ed and accepted the 

government's hybrid theory (while, at the same time, limiting its mling to the 

state of the technology available to the government in the district at that 

time), but it declared the result "unsatisfying" given Congress's lack of clear 

guidance regarding the appropriate standard for law enforcement access to 

prospective cell site data. 89 

Even the DO] has acknowledged the need for legislation to clarify the 

standard governing compelled disclosures of prospective cell site data. The 

DO], however, carefully limited its recommendation to "cell tower 

infornlation associated with cell phone calls," which is perhaps the particular 

area where the DO] seeks specifically to retain the more nimhle and efficient 

investigative standard provided hy the hyhrid order,90 as opposed to the 

higher probable cause standard.91 Tn the DOl's view, "[s Jome courts ... have 

conHated cell site location information with more precise GPS (or similar) 

location infonnation"n and, as previously noted, they are already advising 

prosecutors to seek probable cause warrants for "more precise" GPS 

location data. 

With location infonnation-including single cell tower data-becoming 

only more precise over time and courts continuing to search for an illusory 

"intended" congressional standard to govern law enforcement access to 

prospective location data, the search for clarity remains an uncertain one at 

best in the absence of congressional action. 

13. LEGAL DACKGROUND FOR HISTORICAL CELL SITE DATA 

Tf the uncertainty over what standard to apply to prospective location 

information has left courts without a strong sense of direction, that 

88. See It! I~ Tf~D.N.Y. Applicalion, 415 F. Supp. 2d at 213 n.3 (reviewing a letter from 

Verizon's Court Order Compliance Manager "which states that the information sought will 

only 'identify the general area that the target mobile phone located at the time of a specific 

call' and that it 'cannot pinpoint the exact location of the mobile phone' "). 

S9. In re elD.N.Y. Application, 405 fi. Supp. 2d at 442. 

90. Senale Judiiiary 2011 ECPA Hearing, mpranote 7, at 5 (testimony of ]runes A. Baker). 

91. Mr. Baker explains earlier in his congressional testimony that "if an amendment 

were unduly to restrict the ability of law enforcement to quickly ancl efficiently cletermine the 

/"eI2erallocatioll of a terrorist, kidnapper, child predator, computer hacker, or other dangerous 

criminal, it would have a very real and very hwnan cm t." Id. at 6. 

92. Mr. Baker's testimony does not cite to specific examples where the DO] believes 

courts have conflated cell site information with more GPS location information. See id. at 7. 
98 

142 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

confusion is becoming even more pervasive with regard to historical cell site 

data. Lower courts are now beginning to split over the proper access 

standard to apply to it as well. In this context, as with prospective cell site 

location data, 18 U.s.c. § 2703(c) pennits the government to compel "a 

provider of electronic communications service or remote computing service 

to disclose a record or other information pertaining to a subscriber to or 

customer of such service (not including the contents of communications) 

only when the government entity ... obtains a court order for disclosure 

under subsection (d) of this section."93 Stated more simply, a D Order 

"compels [production of] all non-content records."94 

1. The DOn Intetpretation of tbe Stam/arc! fir Obtaining Historical 

Cell Site Data 

The DOJ takes the position that historical cell site infonnation satisfies 

each of the three elements necessary to fall within the scope of 18 U.s.c. 

§ 2703.95 First, a cell phone company is a provider of "electronic 

communications service" to the puhlic.96 Second, "cell site infonnation 

constitutes 'a record of other infonnation pertaining to a suhscriher or to a 

customer of such servIce (not including the contents of 

communications).' ,m More specifically, historical cell site information "is a 

record stored by the provider concerning the particular cell tower used by a 

subscriber to make a particular cell phone call, and is therefore 'a record or 

93. 18 U.s.C § 2703(c) (2010). 

94. Orin S. Kerr, A UJer's Guide to tbe Stored C.ommllnications Act, and a ~gislator's Guide to 

Amending Jt, 72 GEO. WASH. L. REV. 1208,1222 (2004). 

95. Brief for the United States at 8-9, In re the j\.pplication of the US. for an Order 

Directing a Provider of Elec. C:ommc'n Servo To Disclose Records to the Gov't (Appeal of In 

re T¥~D. Pa. Appliea/iM), 620 F.3d 304 (3d Cif. 2(10) (No. 08-4227), 2009 V.?L 3866618. 

96. Id. at 10. The Wiretap j\.ct and SeA define electronic communication service 

("FCS'') to mean "any service which provides to users thereof the ability to send or receive 

wire or electronic communications." 18 USC §§ 2510(15), 2711(1). Cell phone service 

prov-iders provide their customers ,,-ith the ahility to send "wire communications," and thus 

they are providers of electronic communications service. See § 2510(1), (15). Moreover, the 

DOT takes the position that: 

[aJ "wire communication" necessarily involves the human voice. See 

§ 2510(1) (defining "wire communication'') and § 2510 (defining "aural 

transfer"); S. Rep. No. 541, 99th Cong., 2d Sess. 11 (1986), reprinted in 

1986 U.S. Code ConK & j\.dmin. News 3555, 3565 ("cellular 

comlllunicatiom-whether they are he tween two cellular telephones or 

between a cellular telephone and a 'land line' telephone-arc included in 

the definition of 'wire communications' and are covered by the statute"). 

Brief for the Cnited States, supra note 95, at 11 n.lO. 

97. Brief for the Cnited States, slpra note 95, at 11. 
99 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 143 

other infonnation pertaining to a subscriber or customer.' ,,98 Finally, "cell 

site information is non-content information, as it does not provide the 

content of any phone conversation the user has had over the cell phone."99 

Based on this analysis, prosecutors and agents regularly use D Orders to 

compel historical location information from third-party providers. 

2. Judicia! Interpretatiotl of the Standard for Obtaining HiJtorz{'(l! 

CellSite Data 

Lower courts have, for the most part, accepted the govenunent's use of a 

D Order to compel historical cell site infonnation.lOo However, one circuit 

court has held that there may he circumstances in which a judge can require a 

probable cause showing before authorizing a government-compelled 

disclosure of historical cell site information. 

a) The Third Circuit Finds That Magistrate Judges Have the 

Discretion To Require Prohahle Cause 

A govemment appeal of a magistrate judge's opinion101 denying the use 

of a D Order to compel historical cell site data led the Third Circuit to 

consider whether a D Order hased on "specific and articulahle facts" can be 

sufficient to allow the government to compel the production of historical cell 

site data and whether, in some cases, a court should apply the I'ourth 

Amendment's probable cause requirement in place of the more relaxed 

provisions of the SCA goveming the disclosure of historical cell site 

infonnation. 102 The Third Circuit held that historical cell site data "is 

obtainahle under a § 2703(d) order and that such an order does not require 

98. Id (citing In re S.D.N.Y. ApplicatioN, 405 F. Supp. 2d 435, 444 (s.nN.Y 2005), 'Uld 

noting that cell site data is "inf01mation" and "'pertainls r to a subscriber or customer of 

cellular telephone serv-ice"). 

99. Id (citing 18 U.s.c. § 2510(8) and defining the "contents" of communications to 

include information concerning its "suhstance, purport, or meaning"). 

100. See In re Applications of the U.S. for Orders Pursuant to Title 18, U.S. Code, Section 

2703(d), 509 F. Supp. 2d 76, 82 (D. _\1ass. 2007) (granting the government's application for 

historical cell site infounation based on the govemment's stahltory analysis of ·18 U.s.c. 

§§ 2703(c), (d»; id. at 79 n.5 (collecting cases where courts have assumed or applied in dicta 

that compelling disclosure ofhistorica1 cell site data is proper under § 2703(d) of the SC:A). 

101. In re Application of the U.S. for an Order Directing a Provider of Elec. Commc'n 

Servo To Disclose Records to the Gov't (In re lVD. Pa. Application), 534 F. Supp. 2d 585 

(\VD. Pa. 2008). On appeal from the Magistrate Judge to the District Court, the court 

"recognized 'the important and complex matters presented in this case,' but affirmed in a 

two page order without ana1ysis." Appeal ofItz re WD. Pa. Ajplicatiofl, 620 F.3d 304 (3d (;if. 

2010) (citing III 1~ Jl?'D. Pa. /lppli({ltion, 534 F. Supp. 2d 585). 

102. Appeal olIn re lV.D. Pa. Appliiatioll, 620 [i. 3d 304. 
100 

144 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

the traditional probable cause determination.,,103 The Third Circuit also 

found, however, that magistrate judges have the discretion to turn down a 

government application for a D Order even when the D Order standard has 

heen satisfied and, instead, require a prohahle cause showing. This 

determination is based upon the Third Circuit's reading of D Order statutory 

language as "language of pennission rather than mandate."104 The extent to 

which a magistrate judge has discretion to deny a D Order is unclear, as the 

opinion merely instructs that the option to require a warrant "be used 

sparingly because Congress also included the option of a § 2703(d) order," 

that judges do not have "arhitrary" discretion, and in those cases where a 

magistrate judge does require a warrant, she must "make fact findings and 

give a full explanation that balances the government's need (not merely 

desire) for dle information widl the privacy interests of cell phone users.,,105 

In his concurring opinion, Judge T ashima noted his agreement with most 

of the reasoning of the majority opinion, hut he was concerned that 

"contradictory signals" leave magistrate judges and prosecutors with a lack of 

"standards by which to judge whether an application for a § 2703(d) order is 

or is not legally sutlicient."lUG Judge Tashima explained that "the majority 

suggests that Congress did not intend to circumscribe a magistrate's 

discretion in deternlining whether or not to issue a court order, while at the 

same time, acknowledging that [o]rders of a magistrate judge must be 

supported hy reasons that are consistent with the standard applicahle under 

the statute[.], ,,11'7 Contrary to the majority's statement that "a magistrate 

judge does not have arbitrary discretion," Judge 'l'ashima suggests that the 

majority's opinion perpetuates exacdy that, because: 

it provides no standards for the approval or disapproval of an 

application for an order cU1der § 2703(d) [and it] vests 

magistrate judges widl arbitraty and cU1cabined discretion to grant 

103. Id at 313. 

104. Id at 316 ("We begin wiili the text. Section 2703(d) states that a 'court order for 

disclosure under subsection (b) or (c) may be issued by any court iliat is a court of competent 

jurisdiction and sbdll issue only if' the intemwdiate standard is met. 18 U.s.c. § 2703(d) 

(emphasis added). We focus first on ilie language that an order 'may be issued' if the 

appropriate standard is met. This is the language of permission, rather than mandate. If 

Congress wished that courts 'shall,' rather than 'may,' issue § 2703(d) orders whenever ilie 

intelmediate standard is met, Congress could easily have said so. At the very least, the use of 

'may issue' strongly implies court discretion, an implication bolstered by the subsequent use 

of the phrase 'only if' in the same sentence."). 

105. Id at 316, 319. 

106. Id at 320 (Tashima,]., concurring). 

107. Id. 
101 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 

or deny issuance of § 2703(d) orders at the whim of the magistrate, 

even when the conditions of the statute are met1U8 

145 

Tndeed, the very instability that currently plagues the prospective cell site data 

legal landscape might also "fester" with respect to historical access standards 

if the Third Circuit's "rule," giving magistrate judges discretion to deny a D 

Order without standards or guidance about when such denial is appropriate, 

were to become the law of the land.!09 

Tn the wake of the Third Circuit's opinion, some magistrate judges who 

once granted access to historical cell site data with a D Order are now 

revisiting that practice. In ~fagistrate Judge Smith's recent opinion, however, 

the court placed more significance on "new technology" that has "altered the 

legal landscape even more profoundly than the new caselaw."!!O Judge 

Smith's opinion meticulously documents the changes in technology leading 

to his determination that "court decisions allowing the Government to 

compel cell site data without a probable cause warrant were based on 

yesteryear's assumption that cell site data (especially from a single tower) 

could locate users only imprecisely."!!! After establishing the state of current 

technology and its rapid pace of change in the direction of increased accuracy 

for the factual record, Judge Smith conducted a constitutional analysis and 

ultimately concluded that a compelled lvarrantle.r.r disclosure of sixty days of 

historical cell site data violates the Fourth !\mendment.ll2 

b) The nc. Circuit's "Mosaic Theory" 

Prior to Judge Smith's opinion, ~fagistrate Judge Orenstein, another 

judge who previously granted requests for historical cell site data pursuant to 

a D Order, also denied the government's application absent a warrant based 

108. Id 

109. For a more extended analysis and critique of the Third Grcuit opinion, see Orin S. 

Kerr, Third Circuit Rules Thdt Magistmte Judges Nm;e Discretioll To Reject NOt/-U'f1I7Wlt COllrt Order 

/lpplications and Require Sedrch IP'm'"rants To Obtain Histon,'al Gl! Site Records, VOLOKII 

~ONSP11L"CY (Sept. S, 2010), http://volokh.com/201O/09/0S/third-circuit-rules-thatmagistrate-judges-have-discretion-to-reject-court-order-application-and-recluire-search-war 

rants-to-o btain -histol~cal-cell-site-records I. 

110. Ttl re Application of the C.S. for Historical Cell Site Data (Til re 2010 SD. Tex'. 

/lpplicdtion), 747 F. Supp. 2d 827 (s.n Tex. 2010). 

111. Id at S30. 

112. The court's reasoning can be summarized as follows: (1) lmder current location 

technology, cell site infolmation reveals non-public information about constitutionally 

protected spaces; (2) historical cell site records are subject to Fourth Amendment protection 

under the prolonged surveillance doctrine of United States v.lvIaynard, 615 F.2d 544 (nC Cir. 

2010); and (3) the gnvemment has not demonstrated that the location data sought was 

vollUltarily conveyed by the user and therefore Smith 2). lvIary!alld, 442 C.S. 735 (1979), does 

not eliminate a legitimate expectation of priyacy. 
102 

146 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

on a probable cause showing.ll3 In finding the government's D Order 

application for historical cell site data over a fifty-eight-day period to be an 

unreasonable search and seizure under the Fourth Amendment,114 Judge 

Orenstein's opinion relies heavily on a recent D.C Circuit Fourth 

!\mendment decision, United States I). J'vfr!}l1ardll' The court in NTqynard 

considered whether the government's warrantless use of a GPS device placed 

on a vehicle to track a suspect's movements for twenty-eight days, twentyfour hours a day, was an unreasonable search under the Fourth Amendment. 

In concluding that the long-tenn GPS surveillance of movements exposed to 

puhlic view was a search,116 the lI,fqynard court recognized a novel "mosaic 

theory" of the Fourth !\mendment.'J7 Specifically, the court explained: 

Prolonged surveillance reveals types of intormation not revealed hy 

short term surveillance ... [and] can reveal more ahout a person 

than does any individual trip viewed in isolation .... A person who 

knows all of another's travels can deduce he is a weekly church 

goer, a heavy drinker, a regular at the gym, an unfaithful hushand, 

an outpatient receiving medical treatment, an associate of particular 

individuals or political groups-and not lust one such tact ahout a 

person, hut all such tactS.1lS 

As Professor Orin S. Kerr observes, under the mosaic theory, a court 

determines whetller govemment conduct is a search "not by whether a 

particular individual act is a search, but rather whether an entire course of 

conduct, viewed collectively, amounts to a search."ll0 Individual acts that 

113. In re Application of the U.S. for an Order Authorizing Release of Historical CellSite Info. (If? re 2010 ED.N.Y /lpplicatio12), 736 F. Supp. 2d 578 (EDN.Y 2010). Btlt Jee 1121~ 

Application of the U.S. for an Order Authorizing Disclosure of IIistorical Cell Site Info. for 

Tel '-.,"0. [redacted], Mise. '-.,"0.11-449, at 5 (DD.C Oct. 3,2011) (Lamberth, C.].), alimlable at 

http://legaltimes.typepad.com/ files/lambertluuling.pdf (holding that a D Order pelmits the 

govet11ment to compel disclosure of historical location data without a probable cause search 

warrant and that Alaynard does not control the question). 

114. In rr! 2010 ED.N.YApplicatiotl, 736 P. Supp. 2d at 582. 

115. United States v. '.1aynard, 615 F.3d 544 (D.C CiL 2010), reh'g denied sub n0171. United 

States v Jones, 625 F.3d 766 (nC Cir. 2010), ajj'd, 132 S. Ct. 945 (2012). 

11(,. Tn reaching its decision, the court explained how the reasoning of KllottJ did not 

foreclose the conclusion that long-term surveillance constitutes a search. lVIay12ani, 615 b.3d 

at 556-58. Indeed, the Court interpreted the Knottr opinion as reserving the que,tion of 

whether prolonged use of a beeper device would relluire a warrant. lei. at 556. The court 

acknowledged, however, tlnt appellate courts in tllree other circuits have reached opposite 

conclusions under KrLOtts. Ttl at 557-58. 

117. Itl at 562. 

118. Id (footnote omitted). 

119. See Orin S. Kerr, D.C CIrcuit Introdtlces '~VIosaic Theory" of Fotll1h /lmendJne12t, Holds 

GPS i"loniton'tlg a Fotlrth AJnelldJnent Sean-h, VULUKH CUGSP1KACY (Aug. 6, 2010), http:/ / 
103 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 147 

may not, in their OV.'11 right, be searches can become searches when 

committed in particular combinations.12o Thus in lvIClYl1afd, the court does not 

look at individual data recordings from the GPS device to determine 

whether, for example, individual trips are searches. 121 Instead, "the Court 

examines the entirety of surveillance over a one-month period and views it as 

one single 'thing' " subject to Fourth Amendment analysis. 122 But at what 

point would a single act or a series of acts amount to the prolonged 

surveillance that triggers the mosaic theory and how does a prosecutor, 

judge, or defense attorney recogni:oe the phenomenon? The AIc!yltard court 

vves no real e;uidance in this regard. 123 Indeed, the Solicitor General in the 

government's brief filed in JOlles (formerly Mqyl2r1rd) 124 has argued: "[T]he 

'mosaic' theory is unworkable. Law enforcement officers could not predict 

when their observations of public movements would yield a larger pattern 

and convert legitimate short-tenn surveillance into a search. Courts would be 

hard pressed to pinpoint that moment even in retrospect.,,125 

\v'hile acknowledging primary factual differences hetween the real-time 

GPS vehicle tracking in l'vft:gJZard and the government's application for two 

months' worth of historical cell site data, Judge Orenstein Ends the lVlqYlIard 

opinion "persuasive" support for his analysis that the Fourth Amendment 

volokh.com/ 20 1 0 / 0 8/06/ d -c-circuit -in trod uces -mo s aic-theory-of-fourth -amendmentholds-gps -m oni toring-a-fourth -amendmen t -search / . 

120. Id 

121. Id. 

122. Til 

123. In United States v. LlleVaJ-I'erez, 640 F.3d 272 (7th Gr. 2011), the Seventh Circuit 

considered whether AIaynard applied to a 60-hour, "factually straightforward" warrantless 

GPS surveillance. ld. at 274. In determining that Nlaytlard did not apply to the case, the 

majority opinion reasoned that },Jayllard's 28-day surv-eillance was much lengthier than the 

60-hour surveillance before the Seventh Circuit and the "single trip" in the instant case did 

not "expose or risk exposing" the "twists and turns" of the defendant's life, "including 

possible criminal activities, for a long period." Til at 274. In concluding .Mayfldrd did not 

apply, however, the majority emphasized "the present case ... is not meant to approve or 

disapprove the result the D.C c:ircuit reached under the facts of that case." ld. at 274 n.3. 

The concurring and dissenting opinions in CUel'aJ-Perez do provide some analysis of il,.Iaynarei. 

Indeed, the concurring opinion generally finds Maynard'J mosaic theory "unworkable," with 

Judge Flaum indicating that it is not "obvious" to him where the /V/a)lllard G:mrt would 

"draw constitutional lines around Cuevas-Perez's sixty-hour Journey." ld. at 282. In contrast, 

Judge Wood's dissent rejects the majority's "single trip" description, finding much more 

similarity between Cuevas-Perez's "60 hour odyssey across 1,650 miles" and the prolonged 

surveillance in i1Jayllarei. lei. at 293. 

124. See _fupra-note 115. 

125. Brief for the United States at 14, United States v .. Jones, 132 S. Ct. 945 (2012) ("-0. 

10-1259), 2011 \X'l. 3561881. Indeed, Respondent Jones does not employ the AIaynard 

"mosaic theory" in his brief to the Supreme Court. See Brief for Respondent Antoine Jones 

at 45,]0I!eJ~ 132 S. Ct. 945 (2012) (No. 10-1259),2011 \X1L 4479076. 
104 

148 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

requires the government to obtain a warrant to compel the location 

infommtion.126 Lower courts' reliance on Afayllard's "mosaic theory," 

however, raises questions, once again, about the viability of a series of cases 

that give prosecutors and judges little to no guidance ahout when and what 

amount of location data is subject to Fourth !\mendment protection. Judge 

Orenstein, for example, found that fifty-eight days of historical cell site data 

required a warrant under d1e reasoning in Aiaptard but, in a later opinion 

applying l\!fC!Yltani, he granted an application for discreet amounts of data 

spanning a twenty-one-day period under a D Order.127 Whle such opinions 

may be heralded as a "victory" for privacy interests hecause, among other 

things, they have the effect of destabilizing the government's use of the D 

Order, they serve neither privacy nor law enforcement interests insofar as 

they perpetuate a legal landscape in which lower courts continue to "search," 

in vain, for the appropriate standards to apply. 

J. The Jones Decision 

Notwithstanding such criticism of the mosaic theory in l-.1aytlard, the 

concurring opinions in United S tate.1 I}. Jom.r 12R suggest that, in some future 

case, there may be five votes for a mosaic-type Fourth !\mendment theory 

holding that "the use of longer term GPS monitoring in investigations of 

most offenses impinges on expectations of privacy.,,129 Indeed, Justice Alito's 

126. In re 2010 ED.N.¥. Application, 736 F. Supp. 2d 578, 584 (E.D.NY 2010). This 

~I\rticle does not focus on appropriate standards for law enforcement use of GPS tracking 

devices installed on vehicles-which do not involve compelled disclosures from third-party 

liCPA-covered providers-and which, therefore, as a matter of policy, may implicate slightly 

different equities and interes ts for Congres s to consider when drafting legislation. 

127. In re Application of the US for an Order Authorizing Release of Historical CellSite Info., 1"0. I1-MC-OIB, 2011 WL 679925 (TI.DS.Y. 2011). The gov-ernment's 

application for historical cell site data sought information from one phone for a three-day 

period, a six-day period from the same phone commencing less than a month later, and a 

twelve-day period from a second phone believed to have been used in furtherance of the 

offenses under investigation. Id. at Xl. The court distinguished the result of the instant case 

from that of l'vIqynard primarily hecause the court could not "assume that the information 

gleaned over such shorter pel~ods, separated by breaks of weeks or months, would 

necessarily be as revealing as the sustained montll-long monitoring at issue in l'vIqynard." Id. at 

*2. Tn making this distinction, however, the court acknowledged that "any such line drawing 

is, at least to some extent, arbitrary and the need for such arbitrariness arguably undC1mines 

the persuasiveness of l'vIqynard, and of [this court's] prior decisions." Id. fior further analysis 

and C1~tique of this decision, see Orin S. Kerr, AppZyillg fhe ~MoJaic Theory of fhe Fourth 

AmeJldmelit to Disc!osim a/Stored Records, VULUKH CU'ISP1KACY (Apr. 5,2011), http://volokh. 

com/20ll /04/05/ appl ying-the-mosaic-theory-of-the-fourth-amendment-to-disclosure-ofstored-records/. 

128. 132 S. O. 945 (2012). 

129. Id. at 964 (jllito,]., concurring). Justices Ginsburg, Breyer, and Kagan joined Justice 

~AJito's concurrence. \V"hile Justice Sotomayor did not join the ~AJito concurrence, she states 
105 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 149 

concurrence invokes the novel aggregative Fourth Amendment theory first 

articulated by the D.C. Circuit in AfqYllard. The Alito concurrence posits that 

"relatively short-term monitoring of a person's movements on publie streets 

accords with expectations of privacy that our society has recognized as 

reasonable" while law enforcement's "secretly monitor[ing] and catalogu[ing] 

every single movement of an individual's car for a very long period" does not 

accord with reasonable expectations of privacy.Du Likewise, lVlaywrd 

previously recognized that "[p]rolonged surveillance reveals types of 

infornlation not revealed by short term surveillance.,,131 

\v'hile Justice I\lito's concurrence applies the Katzm "expectation-of 

privacy test," the majority opinion, authored by Justice Scalia, bases its 

holding partially on a trespass t11eory: "We hold t11at t11e Government's 

installation of a GPS device on a target's vehicle, and its use of t113t device to 

monitor the vehicle's movements, constitutes a 'search.',,133 Justice Scalia 

defines the offending conduct further stating "the Government physically 

occupied private property for the purpose of ohtaining information."J)4 

Consequently, though "[t]respass alone does not qualify [as a search]," a 

search does occur when it is "conjoined" with "an attempt to End something 

or to obtain information.,,135 

Justice Alito criticizes this approach because, among other things, it 

"largely disregards what is really important (the me of a CPS for long-term 

tracking) and instead attaches great significance to something that most 

would view as relatively minor (attaching to the bottom of a car a small, light 

object that does not interfere in any way with t11e car's operation).,,136 Indeed, 

the attachment-focused majority opinion does not address instances where 

the use of GPS solely involves the transmission of radio or other electronic 

in her own concurrence, "1 agree with .Justice _I\LITO that, at the very least, 'longer term CPS 

monitoring in investigntions of most offenses impinges on eX'Pectations of privacy.' " Td. at 

955 (Sotomayor,.J., concurring). See afJo Orin S. Kerr, IfC"bat'J {be Status of {be Afosai( TbeO/y 

After Jones?, VOLOlili ~OI'-SP1KACY Gan. 23, 2012), http://volokh.com/2012/01/23/whatsthe-status-of-the-mosaic-theory-after-jones/ (explaining that the mosaic theory "lives"). 

130. 1olles, 132 S. Ct. at 964 (jllito, J, concurring). 

131. United States v. Maynard, GIS F,3d 544, 5G2 (D.c. Cif. 2(10), reb'g denied sub 110111. 

United States v.lones, 625 b.3d 766 (nc. Cir. 2010), aJl'd, 132 S. Ct. 945 (2012). 

132. Katz v. Cnited States, 389 C.S. 347 (1967). "As Justice IIarlan's oft-quoted 

concurrence described it, a Fourth Amendment search occurs when the government violates 

a subjective expectation of privacy that society recognizes as reasonable." Kyllo v. United 

States, 533 U.S. 27,33 (2001) (citing Katz, 389 U.S. at 361). 

133. 1olles, 132 S. Ct. 945. 

134. Id. 

135. Id. at 951 n.5. 

136. Id. at 961 Vllito,J., concurring). 
106 

150 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

signals not enabled by tile government's direct physical trespass-such as 

tracking a target's cell phone.137 \"\?hile acknowledging that govemment 

tracking though electronic means without actual physical trespass may be "an 

unconstitutional invasion of privacy," the majority opinion asserts "the 

present case does not require us to answer that question." I,R ~Moreover, the 

majority opinion criticizes the line-drawing problems the Alito concurrence 

presents: 

[I]t remains cUlexplained why a 4-week investigation is "surely" too 

long and why a dmg-trafficking conspiracy involving substantial 

atTlOWltS of cash and narcotics is not atl "extraordinaty offens[e]" 

which may pel1Tlit longer observation. \'/hat of a 2-day monitoring 

of a suspected purveyor of stolen electronics? Or of a G-month 

monitoring of a suspected terrorist~139 

Indeed, consistent with the difficulties lvlqytzard raised, Justice Alito's 

adoption of a mosaic-type theory provides no significant guidance to law 

enforcement, judges, and industry about when Fourth Amendment concerns 

materialize: "\Ve need not identify with precision the point at which the 

tracking of this vehicle became a search, for the line was surely crossed 

before the 4-week mark."110 Rather than creating clarity in the law, the Alito 

concurrence perpetuates, perhaps even intensifies, the confusion surrounding 

appropriate law enforcement standards for access to location data. 

4. The Imporlance of Legi!lative CZmi{y ill the Face of Rapid 

Technological Change 

Scholars and advocates may legitimately disagree about Fourth 

Amendment theory and about courts' application of the Fourth Amendment 

to government-compelled disclosures of cell site data. :\!otwithstanding this 

constitutional dehate, however, the current pace of technological change in 

this area has given rise to inordinately difficult analytical challenges and 

highlighted a consequent need for Congress to clarify or amend the law. 

Chief among these challenges is the current instability in the law created 

when courts must struggle to find congressional intent in laws that predate 

the current state of location technoloS'Y-in short, to find intention in the 

ahsence of a stahle ohject. In the face of this ultimately futile search for 

historical interpretive authority, courts must grapple directly with the legal 

137. Td. at 953 ("Situations involving merely the transmission of electronic signals 

without trespass would remain subject to the Katz analysis."). 

138. Id. 

139. Id. (citation omitted). 

140. Id. at 964 VlJito, J., concurring). 
107 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 151 

implications that enormously complex and quickly evolving location 

technologies raise in conjunction with the facts of a given case. Finally, 

courts must try to perform the foregoing analysis while simultaneously 

confronting any implications the rapid rate of ch:mge in the capahilities of 

location technology might have upon the reasonable scope of their decisions. 

To avoid these difficult acts of legal navigation, policymakers should enact 

laws containing dear standards that strike the right balance among law 

enforcement needs and privacy and industry interests. These standards must 

also be flexible enough to accommodate the pace of technological change to 

a deeree that renders it a moot consideration in any court's analysis. 

C. QUESTIO'-JS }L\ISED BY THE Two EXISTING STA'-JDARDS FOR 

COMPELLING DISCLOSURE OF LOCATIOK DATA 

1. f// hat DoeJ a "D" Order Require the GOlJertlJtJellt '1"0 S hOld 

The call hy some advocates for a prohahle cause standard to govern all 

law enforcement compelled disclosures of location data is, of course, a 

recognition that the D Order atTords a less stringent showing by law 

enforcement than that required to meet probable cause.HI Specifically, to 

obtain a D Order, law enforcement must provide "specific and articulable 

facts that there are reasonable grounds to believe" that the information to be 

compelled "is relevant and material to an ongoing investigation.,,'42 Some 

scholars have referred to the D Order standard as a "Terry-stop" standard, a 

reference to Terry II. Ohio, where the Supreme Court created the reasonable 

suspicion standard for sidewalk stop-and-frisk encounters. 143 The 'l"CI?Y 

standard is met "when an officer 'point[s] to specific and articulable facts 

which, taken together with rational inferences from those facts, evince more 

141. See H.R. REP. No. 103-837, at 31 (1994) (indicating that the D Order is "an 

intermediate standard ... higher than a subpoena, but not a probable cause warrant"). 

142. 18 lJ.S.C § 2703(d) (2010). 

143. 392 U.S. 1, 30 (1968); see also CHRISTOPHER SLOBOGIN, PRIV_"CY AT RISK: THE 

NEW GOVER'fMCNT SURVCILLANCE Al'D THE FOCRTH _1\',IENDME'fT 175-76 (2007) 

(arguing that the D Order standard, although perhaps intended to be more demanding than 

the relevance standard required for a subpoena, may not be much different: "leJven if 

material is meant to augment rele,'ant, it does not add much; materiality, in evidence law, 

means merely that the evidence be lOgically related to a proposition in the case"); Freiwald, 

supra note 52, at 692 (discussing that the D Order standard permits much broader inquiries 

into a much wider range of targets than the probable cause standard); Paul Ohm, Probably 

Probable Calise: The Dimimshin.R Im/!0I1allce OfJIIJtijZ,{1lioll Standards, 54 MIl'N. L. REv. 1514, 

1521-22 (2010) (noting that the D Order standard "is probably much more stringent than 

the mere-relevance subpoena standard" and is set by Congress "at a high enough level to 

prevent police fishing expeditions"). 
108 

152 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

than an inchoate and unparticularized suspicion or hunch of criminal 

activity.' ,,144 

From a practical standpoint, the D Order standard facilitates law 

enforcement access to non-content records at the early stages of an 

investigation, when the government is unlikely to meet the higher probable 

cause standard. In a recent case not involving location information, the DOJ 

asserted that the D Order standard "derives from the Supreme Court's 

decision in T er~y" and thus "is no more onerous than the TeT~Y rule.,,145 As 

such, the word "material" in iR usc. § 2703(d) "does not transform the 

§ 2703(d) standard into one that requires a showing that the records sought 

are 'vital,' 'highly relevant,' or 'essential.' ,,146 Indeed, the scope of a D Order 

may be "appropriate even if it compels disclosure of some unhelpful 

infonnation," as "'§ 2703(d) is routinely used to compel disclosure of 

records, only some of which are later determined to be essential to the 

governmenis case.' ,,147 For example, if investigators compel location 

information for every cell phone in the vicinity of a murder scene for a 

specific period of time, they are likely to obtain imle!'a12t location information 

about innocent people who just happened to be in a particular place at a 

particular time in addition to information about the presence of the murderer 

or witnesses who might have seen the murderer. 

Broadening the scope of a request for location information heyond, hut 

in relation to, a known target can advance an investigation strategically. Law 

enforcement, 111 certa111 circumstances, might request the location 

infonnation of all individuals who were called by or made calls to a particular 

target. 118 This practice, sometimes referred to as a "community of interest" 

request, is of particular concern to privacy advocates,149 but it can, for 

144. United States v. Mason, 628 F.3d 123, 128 (4th Cir. 20lO) (quoting United States v. 

Branch, 537 F.3el 328,3% (4th Cir. 2(08». 

145. Government's Response to Objections of Three Twitter Subscribers to Magistrate 

Judge's "1arch 11, 2011 Opinion Denying Motion To Vacate and Denying in Part "1otion 

To Unseal at 8-9, III re Application of the U.S. for an Order Pursuant to 18 e.s.c. § 2703(d), 

2011 WL 5508991 (ED. Va. 2011) (Mise. Nos. 1:11-D_\1-3, lO-GJ3793 & 1:11-EC-3), available 

at http://files.clouelprivacy.ne t/ govemlen t_opp-pel f. 

146. Id at 8-9 (quoting Subscribers' Objections). 

147. Id at S (quoting Magistrate Judge Buchanan's Opinion and Order of March 11, 20U). 

148. See Huwe Judiciary 2010 EC-PA Reju!7Jl Hea1?lIg, supra note 18, at 29-30 (written 

statement of l\lbert Gidari, Perkins Coie LLP) (explaining that with respect to location 

infi:mnation of specific users, many orders now require disclosure of the location of all of 

the associates who were called by or made calls to a target). 

149. Some privacy scholars express strong concems with a standard that "allows the 

government to seek location inf01mation about apparently innocent parties regularly," 

noting that community of interest requests provide law enforcement with infunnation about 
109 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 153 

example, enable law enforcement to identify unknown suspects potentially 

involved in criminal activity with a known target. 1SO 

Law enforcement often needs the ahility to cast a wider investigative net 

at early stages of an investigation and, assuming the government's 

interpretation is correct, the D Order standard facilitates this "overcollection" of information. But insofar as tile D Order standard does 

facilitate an often 11e(eJm~y over-collection of information, to what extent does 

it adequately prevent zl7171ecm'acY over-collection of information? In other 

words, should not the D Order standard explicitly require that a sufficient 

nexus exist between the scope of the location information requested and the 

criminal activity being investigated) 

If so, how should this nexus standard be examined by courts? 

Detennining whether an application reflects a time period tailored to the 

criminal activity heing investigated is one inquiry for courts to make in an 

effort to legitimately cahin the amount of information collected. i\ single 

individuals only tenuously connected to a crune without the judicial ov-ersight that a warrant 

guarantees. See Freiwald, Jupmnote 52, at 718. 

150. Consider the following scenat~o: British authot~ties at an airport package transit xray station in Coventry, Fngland x-rayed a package and discovered a .375 Magml111 revolver 

hidden inside a dlild's toy boat. More packages containing weapons and ammunition 

concealed inside children's toys were also discovered. \X/hen the revolver from the first 

package was removed, agents noticed that the gun's serial number had been filed down, but 

forensic analysis reconstmcted the number, allowing law enforcement to trace the gun back 

to a dealer with a known identity and a Jemale gun pllTchaser with a known identity in South 

Florida. The packages had also been mailed from South Honda via express mail, which 

allowed agents to identify the location, time, and date that the package was mailed. Cameras 

inside those post offices recorded video showing two men mailing the first package 

containing the .3S7 Magnwn rev-olver. No further information identifying those men was 

kno'Wn at the time. It is reasonable to assume that the woman 'Who purchased the revolver 

(whose identity law enforcement had confitmed) called or was called by the men who mailed 

the package. One way to assist law enforcement in identifying the men (who continued to 

mail packages ultimately discovered at Coventry airport) would be to obtain location 

information focused on the uldividuals in contact with the known female gun purchaser. 

This factual scenario is taken from a real case, Unifed SfafeJ v. Cla.Yfon, No. 99-06176 

(S.D. Ha. June 13, 2000) (Ferguson, J), prosecuted by Stephanie Ul 1999-2000 ulVolving a 

cell of IRA operatives who came to the United States, purchased weapons illegally, hid them 

in children's toys and large, hollowed-out computer towers, and mailed them to the Republic 

of Ireland where they would he smuggled into Belfast. This operation was occurring during a 

critical time in the peace process all(i the weapons were intended to replace the cache of 

weapons being turned over as part of the Good Friday Agreements. The factual narrative 

described is condensed to illustrate how a "community of interest" request would have 

assisted in identifying the identities of the men mailing the packages, had such a practice 

heen in use at that time. For more infonnation ahout the case, see Mike Clary, Lax Florida 

LaJils /1ttra,1ed 11Vl, REGISTER-GUARD (Eugene, Or.), June 8,2000, at 6A, al!aiiable at http:/ / 

goo.gI/S6BgC. 
110 

154 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

bank robbery occurring over the course of an hour committed by a few 

suspects, for example, would likely require a narrower collection of 

information than a sophisticated drug conspiracy covering multiple 

jurisdictions with multiple conspirators occupying ditlerent roles and 

perfonning different tasks. Not only would the length of time retlected in the 

bank robbery D Order application likely be shorter than in the drug 

conspiracy application, but the number of individuals targeted (known and 

unknown) might also be fewer. In certain types of investigations, identities of 

targets are not initially known, but locations where crimes or activities 

relevant to determinin8 the identities of suspects are known. \~'hen the 

request for the location data is centered on a place where an activity 

occurred, courts can ensure that the length of the request (i.e., from "Time 

X" to "Time \(") is suHiciently tailored to when tile investigation suggests 

that ti1e suspects were present at ti1e location. Similarly, when community of 

interest requests are made, courts could ensure that the breadth of location 

information requested ahout individuals who called or were called hy a target 

is reasonahle in light of investigative facts descrihed in the application. There 

are, of course, many pennutations of how the scope of a request for location 

data would manifest in a particular investigation. Considering that D Orders 

necessarily facilitate an over-collection of information, however, Congress 

could amend the language of § 2703(d) to ensure that courts are examining 

\vhether a sufficient neAllS exists between the scope of the location 

information requested and the criminal activity heing investigated. 

2. Probable Came of What? 

A strict probable cause standard for the disclosure of location 

infonnation could interfere with legitimate law enforcement objectives. Some 

of the privacy concerns motivating the advocacy for the application of a 

probable cause standard to all law enforcement compelled disclosures of any 

and all location information are discussed later in Part V. At this stage in the 

analysis, however, it is useful to explore how a strict definitional application 

of the probable cause standard-as articulated in Rule 41 151_might unduly 

limit some of the basic law enforcement uses of prospective and historical 

location infonnation to the degree tllat legitimate investigative activities 

151. See FED. R. CRIM. 1'. 41(c) Oisting categol~es of probable cause: "(1) evidence of a 

crime; (2) con trah and, fruits of cl~me, or other items illegally pmsessed; (3) property 

designed for usc, intended for usc, or used in committing a crime; or (4) a person to be 

arrested or a person who is unlawfully restrained"). 
111 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 155 

dependent upon the use of these tools would be inhibited, even thwarted, 

from the start.152 

If required to ohtain a Rule 41 warrant for compelled disclosures of 

location information, the government would need to establish probable cause 

to believe that the location information itself is evidence of a crime.153 In 

some instances, the location of a cell phone, insofar as it reveals a suspect's 

location, would qualify as evidence of a crime. Location information, for 

example, may rebut a defendant's alibi, place a defendant at the scene of a 

crime, or show that a defendant's movements are consistent with activities or 

overt acts alleged in furtherance of a criminal conspiracy. 

But not every use of location infonnation by law enforcement easily fits 

into the "evidence of a crime" element of Rule 41. If, for example, a person 

has committed a crime in the past, her current location may not be evidence 

of a crime, yet there might exist circumstances in which law enforcement has 

a legitimate need to find her. '54 If law enforcement has evidence to suggest 

that a person is ahout to commit a crime, her current location or prospective 

location leading up to the commission of that crime mayor may not, itself~ 

be evidence of a crime, yet our society generally accepts that law enforcement 

has a legitimate need to prevent her from committing a crime. Indeed, when 

addressing the DDP proposal that a probable cause warrant should be 

required for law enforcement access to all location data, Professor Kerr 

posed the question, "probable cause of 2l,hae,155 Is it "prohable cause to 

believe the person tracked is guilty of a crime" or "probable cause to believe 

the evidence of location information obtained would itself be evidence of a 

crime?,,156 Professor Kerr noted that the difference is important hecause, in 

the case of a search warrant, probable cause generally refers to probable 

152. We do not claim to know, nor are we able to anticipate, all of the ways in which law 

enforcement uses prospective and historical location infomlation in investigations. 

153. See In re Application of the U.S. for an Order Authorizing the Release of Prospective 

~ell Site Info., 407 fi. Supp. 2d 134, 135 (DD.C 2(06) (explaining the difference hetween 

the D Order standard and probable cause as being that the latter recjuires a finding that there 

is probable cause to believe that the information sought is itself evidence of a crime rather 

than reasonable grounds to helieve that the infonnation sought is relevant and material to an 

ongoing investigation). 

154. Some courts, however, have cOlutrued the prohahle cause requirement more 

broaclly with respect to tracking devices or cell site data. See, eg., In !~ Application of the 

United States for and [sic] Order: (1) Authorizing the Use of a Pen Register and Trap and 

Trace Device; (2) Authorizing Release of Subscriber and Other Tn Ii:!.; and (3) Authorizing 

the Disclosure of Location-Based Servs., 727 F. Supp. 2d 571, 581-82 (w.n Tex. 2(10). 

155. HouJe Judiciary 2010 r;;C:PA RPfhrm Hearing, Jttpra note lR, at 39 (written statement of 

Prof. Orin S. Kerr, The George Washington Cniv. Law Sch.). 

156. Id. 
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156 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

cause to believe that the infoonation sought is itJcij"evidence of a come.1S7 

Cell phone location data will be evidence of a crime in only certain kinds of 

cases and will not nonnally be evidence of a crime when investigators need 

to learn the current location of someone who committed a past crime. ,oR 

Magistrate Judge Susan K. Gauvey amplified this analysis in a recent 

decision when she concluded that a probable cause search warrant does not 

peonit law enforcement to acquire GPS location infoonation solely to 

execute an arrest warrant. 159 Specifically, the court noted that the 

government's "prohahle cause" theory for ohtaining the CPS location data 

to locate the subject of the arrest warrant was that the "evidence sought will 

aid in a particular apprehension," not that it was evidence of a crime itsele6U 

The government's request was for "broad information concerning ral 

defendant's ongoing location" with no alleged relationship whatsoever 

between the "defendant's ongoing movements and his crime.,,161 The court 

therefore reasoned that, hecause the government had not estahlished the 

"requisite nexus hetween the information sought and the alleged crime, no 

search warrant may issue" for the location data. 162 

:Moreover, in certain circumstances, law enforcement may compel 

historical location infoonation to exdl/de someone from a criminal 

investigation. In that instance, the location infonnation would not, under any 

reasonahle stretch of Rule 41, he evidence of a crime hut rather would serve 

the important function of "clearing" someone of criminal activity. Clearing a 

suspect would thus prevent further investigation, potentially avoiding a 

needless expenditure of government resources and a gratuitous government 

intrusion into his life by focusing the investigation more accurately upon the 

true perpetrator. These are just a few examples of how the "evidence of a 

crime" element of Rule 41 may not encompass important law enforcement 

investigative activities. To the extent that good policy may dictate a probable 

cause standard for location information, that standard would need to 

accommodate the diverse, legitimate uses of location information by law 

enforcement. 

lS7. Id 

158. Id 

159. III re Application of the U.S. for an Order Authorizing Disclosure of Location Info. 

of a Specified Wireless Tel.. No. 10-2188,2011 U.S. Dist. LFXTS 85638 (D. Mel. Aug. 3, 

2(11). 

160. Id at 93. 

161. Id at 105. 

162. Id. 
113 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 157 

IV. LESSONS LEARNED 

Tn 2010, the House Judiciary Subcommittee on the Constitution, Civil 

Rights, and Civil Liberties held three ECP A reform hearings (with Stephanie 

serving as lead counsel). The second of those hearings, and the most 

challenging to conceive and execute, explored issues pertaining to law 

enforcement access of location data (Location Hearing).163 The hearing 

focused on supplying memhers of Congress with the knowledge necessary to 

clarify or propose new law enforcement access standards for location 

information.'64 

Some of the challenges Stephanie encountered in developing this hearing 

sterIllned from factual and policy questions and quandaries that continue to 

inform the search for reasonahle access standards and other reforms that will 

strike the right balance among the interests of law enforcement, consumer 

privacy, and industry. 111is Part discusses these challenges, which now 

motivate and shape the recommendations for the policy framework 

presented later in this Article. 

A. Ac(~UlRINC~ l'~"cl'S To MAlili GOOD POLley Is D1FF1CUl:l' 

Location technology and the uncertain legal landscape governing law 

enforcement access to location information are complex suhjects. As with 

most complicated Issues, Congress needs information from all 

stakeholders-in this case from law enforcement, consumer privacy and civil 

liberties advocacy groups, and industry representatives-to judge the relative 

necessity for legislative action and discern the best directions for policy. 

\'(/hen compared, however, with other ne\v technologies prompting 

Suhcommittee consideration of ECPA reform, such as cloud computing, the 

subject of location-based information and services inspires an unusual degree 

of secrecy on the part of both industry and law enforcement. 

At a later Subcommittee ECP A reform hearing focused on cloud 

computing, five major cloud computing companies testified. 165 Industry 

testimony included explanations of husiness models and services offered hy 

the various cloud companies and a discussion about how current FCP 1\ 

standards are often difficult to apply to cloud services like Google Docs and 

163. See iJJcafiull Heanng, JJoIpranote 19. 

164. See id. 

165. See genem/fy RCP A Reform arid tbe Reilo/Jolt/ofl irl Cloud TJaJeli Computiflg: Hearing TJeforE the 

Submtllm. 011 tbe CiJllstittiliOll, Ciril Ri,gbrs, and Civil LJbmies oftbe H. Cotllm. 011 tbe Judiciary, 111 th 

~ong. (2010) ~lereinafter Goud Da.red Computing Hearing], aluila/;le at http://judiciary.house. 

gov/hearings/printers/l11 th/111-149_58409.PDF. Industry witnesses included representatives 

from Google, Nlicrosoft, Sales force, Rackspace, and Amazon. 
114 

158 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

Google Calendar.166 :Moreover, some of these companies asserted d1at weak 

ECPA privacy protections for information stored "in the cloud," versus the 

full Fourth Amendment protections afforded information stored on personal 

laptops, limits the expansion of the cloud market, particularly to foreign 

customers who are concerned that the U.S. government has overly broad 

access to cloud-stored information. 167 

In contrast to that very public cloud computing discussion, no wireless 

carriers or other providers of location-based services to consumers testified 

at the location hearing. \'(,'bile industry witnesses willingly discussed details 

about cloud-based services, as well as the challenges the law presents for the 

industry's compliance wid1 law enforcement requests for information stored 

in d1e cloud, no similar public discussion occurred vis-i-vis law enforcement 

requests for location infonnation or d1e types of location infonnation 

carriers collect and retain. 

Law enforcement is equally reticent to discuss puhlicly the investigative 

practices and processes they employ to obtain location information. \Vhile 

they willingly talk about how critical location information is for a variety of 

enforcement responsibilities,168 they will confirm only very general 

infom13tion about the acquisition and uses of the location data. Of course, 

\vhen overly detailed information about sources and methods becomes 

puhlic, these sources and methods may cease to he useful investigative 

tools. 169 Rut, unlike Wiretaps or Pen/Trap surveillance, Congress does not 

even have a sense of the number and scope of law enforcement requests for 

166. See id. at 20 (statement of Richard Salgado, Senior ~ounsel, Law Enforcement & 

Info. Sec., Google Inc.). 

167. See id. at 40 (testimony of David Schelhase, Exec. Vice President & Cen. Counsel, 

Salesforce.com) (explaining that customers considering storing their infot111ation in the cloud 

want assurances that the U.S. government will not access their data without appropriate due 

process). 

168. See Smale Judiciary 2011 ECPA Hearing, supra note 7, at 5 (testimony of James A. 

Baker); see aLfO Location Hemil!l'" sHpra note 19, at 60-61 (written statement of Richard 

Littlehale, Assistant Special Agent in Charge, Technical Servs. Unit, Tenn. Bureau of 

Investigation) (describing how cell phone location information frequently permits law 

enforcement an opportunity to fInd and rescue a victim or apprehend an offender in a 

matter of hours). 

169. \Ve are not in a position to assess all of die circumstances where location 

infi:mnation as an investigative tool could become less useful to law enforcement upon more 

disclosure about the method and frequency of this tool. We do note, however, tlnt 

cellphones are increasingly hecoming a necessary tool for society, and as a remIt, it is 

extremely difficult to avoid the possibility of location surveillance without turning off a 

phone, and losing all the benefits of that technology. 
115 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 159 

location infonnation, statistics that would not necessarily require the 

exposure of detailed sources and methods.170 

\v'hile we can dehate the motivations for the lack of detailed infonnation 

in the public record about industry and law enforcement practices pertaining 

to location information, at the end of the day, Congress needs 

comprehensive infonnation to legislate good policy. For both Wiretap and 

Pen/Trap authorities, for example, Congress mandated annual \Viretap and 

Pen/Trap reports, recognizing the need for accurate reporting on law 

enforcement's use of these tools. [71 As Senator Patrick Leahy has stated, 

reporting requirements are a "far more reliable basis than anecdotal evidence 

on which to assess law enforcement needs and make sensible policy in this 

area,,,172 as well as providing some degree of transparency and oversight of 

these surveillance powers. 173 No reporting requirements currently exist for 

location information.l71 Back in 2000, however, the Republican-controlled 

House Judiciary Committee proposed legislation concerning law 

enforcement access standards for prospective location information. 17S This 

bill included new reporting requirements that would have given Congress 

some sense of the scale of law enforcement compelled disclosures, as well as 

the number of people whose data was provided to law enforcement. 17G The 

170. See /!,e/?era!!y Christopher Soghoian, The Law Enforcement Surveillance Reporting 

Gap (Apr. 10,2(11) (unpuhlished mllilUscript), ,lJ)aihbk athttp://ssm.com/ ahstract=lil0662il. 

171. See 18 U.s.C § 2519(2)-(3) (2010) (outlining what the intercepted communications 

report issued by the Administrative Office of the United States Courts must contain). These 

reports are detailed, revealing for each wiretap the city or county where it was executed, the 

type of interception (phone, computer, pager, fax), the number of individuals whose 

communications were intercepted, the numher of intercepted messages, the numher of 

arrests and convictions that resulted from interception, as well as the financial cost of the 

wiretap. See airo id. § 3126. 

172. 145 COKG. REc. 30,868 (1999) (statement of Sen. Leahy). 

173. S. REp. No. 90-1097, at 79 (1968), repnllted 1111968 U.S.C.C.A."-. 2112,2196 ("[rhe 

wiretap reports] are intended to fonn the hasis for a puhlic evaluation of its operation. The 

reports arc not intended to include confidential material. They should be statistical in 

character .... [Tbey] will assure the community that the system of court order electronic 

surveillance envisioned by the proposed chapter is properly administered and will provide a 

basis for evaluating its operation."). 

174. See Soghoian, Jupmnote 170, at 22. 

175. See Elearonic LOln11!llt1ziations Plivacy /lct ol2000, DZ!!,ita! PnlJacy /lct ol2000 and Noti,--e oj 

Electronic },1onlton"tzg Act: the .\ubcolJtlJt. on the ('ollJtitutiOfl, (;ilil Right.r, and (;ild 

l.lberfies of {he H. C0171fTJ. Of! the 106th Congo (2000) [hereinafter House }udiaillJ 2000 

EGA Heari'CgJ. 

176. See Digital Privacy Act, H.R. 4987, 106th Congo (2000). Y\/hile the DO] opposed 

the particular formulation of these reporting requirements because they were overly 

hurdensome, they could he structured to he less onerous on inves tigators and prosecutors. 

See Houfe }udidary 2000 ECP/l Hearing, supra note 175, at 51 (statement of Kevin DiGregory, 

Deputy Assoc. Attorney Gen., Dep't of Justice) ("[T]he imposition of such extensive 
116 

160 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

bill did not become law and now, more than ten years later, Congress has 

little more infonnation than it did in 2000.177 

B. THE SINGULAR ADVOCACY l<'ocus Ol', LAW ENFORCEMENT 

ST,lNDf,RDS HAS N,lRROWED A DISCUSSION THAT SHOULD 

IKCLUDE MINIMIZATION AKD OTHER "DOWKSTRL"M" 

PRIVACY PROTECTIONS 

The advocacy regarding the appropriate standard for law enforcement 

access to location information has largely focused on the DDP Coalition 

principle calling for a Rule 41 probable cause requirement for all law 

enforcement compelled disclosures of location information (historical and 

prospective, regardless of accuracy).l7R This unitary standard, however, is a 

"non-starter" for law enforcement insofar as it will unduly limit the 

acquisition of non-content information at the early stages of an investigation 

and will likely prohibit some basic investigative uses of location 

infommtion.179 Indeed, it is one side of what has appeared to become a rather 

intractahle stalemate. 

The singular advocacy focus on a "high" law enforcement access 

standard unduly limited a discussion of other downstream, post collection 

privacy protections, which were neither included in the DDP proposal nor 

adequately considered publicly. Such additional protections are a signitlcant 

component, along with reasonable access standards, in the broader privacy 

framework proposed in Part VI. Such measures, mandated hy Congress for 

other surveillance authorities, include: minimi7ation, a process by which 

information not relevant to the investigation is purged from law enforcement 

databases;18o notice to individuals whose location information has been 

disclosed to law enforcement at a time that does not harm an ongoing 

investigation;181 and the publication of statistical reports on law enforcement 

use of location surveillance authorities.182 These sorts of protections are one 

reporting recluirements for cyber-crime investigators would come at a time when law 

enforcement authorities are strapped for resources to fight cyber-crime. The reporting 

requirements for wiretaps, while extensive, are less onerous because law enforcement applies 

for such orders relatively rarely. Extending such requirements to orders used to obtain mere 

transactional data would dramatically hinder efforts to fight cyher-crime, mch as the 

distribution of child pornography and Internet fraud."). 

177. See Soghoian, supra note 170, at 23. 

178. See Our Primiples, mpm note 22. 

179. See stlpra Part ll1. 

ISO. See lS U.s.C § 2S1S(S) (2010); SO U.s.C § lS04(a)(5) (2009); id. § lS61 (h) (2) (D). 

181. See 18 U.s.c. § 2518(8)(d) (1998). 

182. See 18 U.s.c. § 2519 (2010). 
117 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 161 

way to balance or offset access standards authorizing broader law 

enforcement collection of data. 

C. THE POLARIZED VIEWS OF LAW liN FORCEMENT AND PRIVACY 

ADVOCATES :'vL\KE CONSENSUS BUILDING DIFFICULT 

It is not particularly insightful to observe that when one side of a debate 

starts from a position that is completely unworkable for the other side and 

will not move, it is ditTicult to build consensus. If, at the end of the day, the 

only standard for location data that is acceptable to privacy advocates is a 

Rule 41 probable cause standard, then they risk letting the proverbial perfect 

he the enemy of the good. The advocacy message for overall ECPA 

reform-while supported through industry participation in the DDP 

Coalition and echoed by strong industry voices outside of the coalition 

calling for Congress to enact clear legal mles and shelter industry from 

liability-was driven primarily by privacy advocates. Thus, the burden to 

suggest new, workable, and more privacy-protective standards falls primarily 

on the shoulders of the community of privacy advocates. This is not an area 

where law enforcement will likely act as a willing catalyst for new access 

standards that place restrictions on their own investigative tools in the name 

of better privacy protections, even if they are prepared to agree to a fair 

compromise in the end. 110reover, law enforcement has strong advocates in 

Congress who will fight against overly broad proposals to restrict 

investigative authorities. Consider, for example, the opening statement by 

then Ranking :'vfemher Sensenhrenner (now Chairman of the House Judiciary 

Subcommittee on Crime, Terrorism, and Homeland Security and author of 

the USA PATRIOT Act) at the Location Hearing. Having clearly read the 

proposal for a unitary probable cause standard, the Ranking :'vfember 

announced, "\X/hile there may very well be a need to clear up the confusion 

in the area of obtaining prospective cell site information, it docs not 

necessarily follow that the appropriate remedy to any amhiguity would he a 

Rule 41 search warrant based upon probable cause."183 

Notwithstanding such strong allies in Congress, however, the DO] 

should carefully measure the practical impact of Jones. While Jones does not 

hold that a warrant is required for the installation and use of a GPS tracking 

device,184 a pmdent prosecutor interested in ensuring that CPS tracking 

183. Location Hearil~g, supra note 19, at 3 (opening statement of ranking member Rep. Jim 

Sensenbrenner). 

184. The Court declined to reach the question of whether a warrant is required to install 

a GPS device. See United States v. Jones, 132 S. O. 945, 954 (2012) ("The Govemment 

argues in the alternative that even if the attachment and use of the device was a search, it was 

reasonable-and thus lawful-under the flourth Amendment because 'officers had 
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162 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

evidence is admissible at trial would, absent further judicial or congressional 

guidance, be wise to obtain one in every instance. Only time will tell whether 

this new strategic necessity will have a measurable adverse impact on law 

enforcement investigations. 

A more urgent concern for the DO], however, should be the threat of 

continued judicial application and expansion of the mosaic theory inspired by 

the signals in the JoneJ concurrences. The signals in the JOlleJ concurrences 

indicate that a majority of the Court could, in the future, incorporate some 

version of the theory into its Fourth Amendment jurisprudence. As we have 

seen, absent clear congressional guidance regarding standards for law 

enforcement access to location data, some courts are already applying the 

mosaic theory to government applications for historical cell location data 

with varying interpretations about how much data forms a mosaic and 

triggers a Fourth Amendment issue.lss Justice Alito's answer for how to deal 

with the thorny line drawing prohlem under a theory that does not define 

when the mosaic materializes is simple: "where uncertainty exists with 

respect to whether a certain period of GPS surveillance is long enough to 

constitute a l'ourth Amendment Search, police may always seek a warrant.,,186 

Dut this simple dictate is hardly a viable one for law enforcement in every 

instance.187 If the DO] finds this potential reality to be unworkable and 

hannful to future law enforcement investigations (as it has suggested in 

congressional testimony),IRR it should engage earnestly in the legislative 

process and be prepared to agree to some reasonable additional privacy 

protections. Indeed, the prospect of a majority that would make the mosaic 

reasonable suspicion, and indeed probable cause, to believe that Uones] was a leader in a 

large-scale cocaine distribution conspiracy.' \Ve have no occasion to consider this argument. 

The Government did not raise it below, and the D.C Grcwt therefore did not address it." 

(citation onaitted»; Jee alJo Orin S. Kerr, [Fha£ Jones DOeJ :\"ot Hold, VOLOKH CONSPIRACY 

(Jan. 23, 2UI2), avmlable at http://volokh.com/2UI2/Ul/23/what-Jones-does-not-hold/ ("IWle 

actually don't yet know if a warrant is required to install a GPS device; we just know that the 

installation of the device is a Fourth Amendment 'search.' ''). 

ISS. See .rupm Section III.B.2.b. 

186. JoneJ, 132 S. Ct. at 964 (jllito,]., concurring). 

187. See Jupm Section III.A3. 

188. See Set/ate Judiciary 2()11 DCPA Hearing, .wpm note 7, at 5 (testimony of James A. 

Baker, _A.ssoc. Deputy Attorney Gen., U.S. Dep't of Justice) (''If an amendment Ito ECl'AJ 

were to unduly restrict the ability oflaw enforcement to quickly and efficiently detenlline the 

general location of a terrorist, kidnapper, child predator, computer hacker or other 

dangerous criminal, it would have a very real and very human cost."). 
119 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 163 

theory the law of the land should concentrate the Department's mind 

wonderfully upon resolving this issue through the legislative process.189 

V. WHAT IS THE HARM, AND WHO CAN ADDRESS IT 

MOST EFFECTIVELY? 

In proposing that Congress reform existing location privacy law, we 

confront a logical threshold question: just what harms would we seek to 

prevent? Wl1en it tlrst enacted the Electronic Communications Privacy Act 

back in 1986, Congress sought to reestablish the balance of interests between 

law enforcement and privacy'00 that had heen upset-to the detriment of 

privacy-by advances in wireless and computing technologies.!9! Congress 

also recognized that consumers might not embrace new technologies if 

privacy interests were not appropriately protected.!n As technology 

continues to develop-simultaneously enriching our lives and facilitating 

more prevalent government (and private) surveillance-Congress, once 

again, is preparing to confront the task of estahlishing an appropriate halance 

among stakeholder equities,193 which prompts us, yet agdin, to ask this 

threshold question. 

In recent years, prominent judges have, in written opinions, described 

and vuiced concern uver the harms assuciated with mudern lucatiun tracking 

technologies. In doing so, they have suggested that Congress, not the 

judiciary, might be in the best position to provide appropriate incentives and 

189. "Depend upon it, Sir, when a man knows he is to be hanged in a fortnight, it 

concentrates his mind wonderfully." JAMES DOSWELL, LIFE OF JOHNSON 849 (Oxford Cniv. 

Press 1960) (1791). 

190. See House Judiciary 2010 ECPA Reform Hearing, supra note 18, at 8-9 (written 

statement of James X. Dempsey, Vice President for Pub. Policy, Ctr. for Democracy & 

Tech.) (discussing balance of interests Congress sought to strike in enacting ECl'A). 

19'1. .il.mong the developments noted by Cong1'ess were '1arge-scale electronic mail 

operations, cellular and cordless phones, paging devices, miniaturized transmitters for radio 

surveillance, and a dazzling array of digitized networks .... " ILR. Illil'. No. 99-647, at 18 

(1986). Privacy, Congress concluded, was in danger of being gradually diminished as 

technology advanced. S. REp. No. 99-541, at 2-3,5 (1986); see also HR REp. No. 99-647, at 18 

(stating that '1egal protection against the unreasonable use of newer sutveillance techniques 

has not kept pace with technology''). 

192. See S. REp. :--':0.99-541, at S (noting that legal uncertainty over the privacy status of 

new fo=s of communications "may lUlllecessarily discourage potential customers from 

using innovative commlUlications systems"); see also H.R. RHl'. No. 99-647, at 19 (noting that 

legal uncertainty over confidentiality "may unnecessarily discourage potential customers 

from using ... lnewJ systems''). 

193. As of the writing of this "'liticie, five separate heal~l1g; 011 E(;PA refonn were held 

dU1~ng the lllth and 112th sessions of Congress (three hearings held in the House Judiciary 

Committee and two hearings in the Senate Judiciary Committee). 
120 

164 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

remedies. \\fe take our cue from these judges and their stated concems to 

identify potential harms Congress should consider when it evaluates the 

relative necessity for legislative action and discems the best policy 

direction. 104 

A. THE GOVERNMENT'S GAZE A'-JD THE PANOPTIC EFFECT 

As we shall see, some judges who have considered cases involving law 

enforcement access to location data posit dlat dle persistent gaze of 

government may itself represent an objective harm to the public.195 In doing 

so, these judges have alluded to surveillance theories found in literature, 

social theory, and philosophy. To evaluate and discuss their conclusions fully, 

we must briefly describe some of that material and how it appears, directly or 

allusively, in their opinions. 

Late eighteendl-century dleories of surveillance as an instrument to 

administer discipline and enforce social control, such as Jeremy Bentham's 

"Panopticon" prison architecture,l96 suggest that the potency of the 

government's gaze is such that, when imposed strategically and with 

suggested if not actual universality and constancy, it becomes internali7ed in 

the very minds of those subjected to its influence as a mechanism of 

rehabilitative discipline. 197 :'vforeover, 13endlam envisioned the Panopticon's 

design as appropriate not only to prisons, but to any environment where 

enhanced discipline is desired: schools, asylums, factories, and more. In 

short, for Bentham, the panoptic gaze of the state could serve as a secular 

version of the all-seeing eye of the Judeo-Christian God, and the normative 

behavioral conformity religious conscience once inspired would be supplanted 

on more certain ground by the discipline this modem gaze could inspire. 

The twentieth-century French social theorist Michel Foucault rigorously 

analyzed Bentham's project in the Panopticon and expanded it into an 

interpretive metaphor for coercive social power. Foucault examines 

"Panopticism" as an instance of modem society's ability to compel 

194. \Xlhat follows in this Section is not an attempt to describe an authol~tative legal or 

philosophical theory of the halIDs inherent in UllJUS tified disclosure of location data, though 

we shall have occasion to allude to law, philosophy, anc1literature in senrice of the task of 

describing those harms as expressed by Judges who have confronted them and chosen to 

discuss them in recent opinions. 

195. See United States v. Cuevas-Perez, 640 F3d 272, 285 (7th Cir. 2(11) (FlalUn, J, 

concurring) ("The constitutional ill of prolonged or mass use of GPS technology would not 

necessarily be based on the infonnation acquired by the device but on the fact of the 

govetnment's gaze."). 

196. See JEREMY DE'lTHAM, THE PA'IOPTICON WRITINGS 29-95 (Miran Dozovic ed., 

1995) (1787) 

197. Id. 
121 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 165 

compliance with its approved behavioral norms through its institutions and 

their various discourses. 198 The presence of modern surveillance mechanisms, 

visible and imperceptible, public and private, promotes the "Panoptic 

effect"-a general sense of being omnisciently observed. The state may 

choose to deploy this effect to amplify and mystify the power of its own 

"gaze" as a coercive instrument, and to promote the internalization of that 

gaze in the service of discipline. I" 

Bentham's plan for the Panopticon was fairly simple: a model prison 

consisting of a central tower surrounded by a ring of prison cells, each of 

them backlit, so that anyone in the tower could see all of the prisoners at 

once. Bentham posited that a single inspector in the tower could control the 

behavior of all of the prisoners through making each prisoner "always feel 

themselves as if under inspection, at least as standing a great chance of being 

SO.,,200 Eventually, since the backlit cells and the tower structure made it 

impossible for prisoners to observe him, the monitor in the tower would 

actually become superHuous and the inmates, having internalized the 

presumption of his continued surveillance, would literally watch theJJ1se!l'es. 

198. See "1ICHEL FOUCAULT, DISCIPLINE & PU'fISH: THE BIRTH or THE PRISO'f 195-

228 (1978). Discourse in this case does not refer merely to the word's common denotation 

as written or spoken communication or debate, but to the word as used in modem social 

theory, particularly the work of Foucault, referring to the Va1~OUS systems oflingu1stic usages 

associated with complex social practices (e.g., law, medicine, religion) deployed as 

instmments of social power, particularly the power of the state. See l"etlera/Jy "1ICHEL 

F01J(:AlJLT, THE ORDER OF THTKGS (1970); MTCHEL FOlJCATJTT, THE ARCHEOLOGY OF 

K'fOWLEDGE (1972). For an extended discussion of the diffuse nature of power in society 

and the role this concept of discourse plays in analyzing how ideas and language encode 

power in social spaces and, therefore, have the potential to playa role in historical change, 

see MICHliL flOUCAUU', T}J)o Lecture.r, it! POWliR!KNOWLEDGli: SliLECIED Il'-l'liRylhWS & 

OTHER WRITI'fGS 78 (Colin Gordon eei., 1980). 

199. It is important to note that more recent writers on "sUlveillance theory" have 

qualified Bentham and Foucault usefully. See, eg., GTILES Dm.ElJ7.E, POSTSCRTPT ON THE 

SOCIETIES OF CONTROL 3-7 (1992) (distinguishing Foucault's "disciplinary" society from 

his own "control" society in critique of the Panopticon); DAVID LYol'-, THEORIZING 

SURVEILUUCE: THE PANOPTICON ,\NO BEYOND (2006); DAVID LYON, SURVEILUUCE 

STUDIES: A'f OVERVIEW 54-62 (2007) (summal~zing contemporary criticism qualifying the 

application of Foucault's analysis to contemporary surveillance). \v11ile the rigor and depth 

of recent surveillance theory is indispensible background to anyone who would consider 

surveillance in all its profundity, its presence in legal opinions to date, which is the focus in 

this Article, has been predominantly restt~cted to metaphorical allusions to Orwell's dystopia 

in 1984 and some consideration of the govemment's "gaze" as discussed in Foucault's 

inte'1,retation of the Panopticon. Since these inte'1lfetive frames are effectively canonical 

and, as such, disseminated commonly enough to dl~ve judicial decision making, as well as the 

appeal hy the judiciary for legislation in this area, we place our own main focus on them at 

this moment in the policy debate. 

200. Jeremy Bentham, Letter V' EsJetltial Poittts a/the Plan, itt BlON'1 HAM, supra note 196. 
122 

166 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

Foucault claimed this intemalization of surveillance made the Panopticon a 

quintessential figure for a peculiarly modem and secular form of state power 

that arose in the Enlightenment, "a new mode of obtaining power of mind 

over mind, in a quantity hitherto without example.,,201 

As modem location surveillance techniques increase in precision and 

their pervasive distribution throughout society becomes known, though the 

instruments themselves may or may not remain invisible, people become 

increasingly aware ot~ and potentially influenced by, a palpable sense of the 

omniscient gaze similar to that produced hy Bentham's prison design. 

Consider, for example, that through the use of modem surveillance 

technologies, a single police onicer can now monitor the movement of tens, 

even hundreds, of targets from the comfort of her desk202 and, because there 

is no statutory notice provided to those under such surveillance, targets have 

no way of knowing if and when they are heing or have heen watched.203 

\~'hile surveillance has traditionally been very expensive in terms of human 

resources (often requiring multiple shifts of agents to watch a single target 

for a nventy-four-hour period), the ubiquity of cellular phones and 

innovations in GPS tracking technology has made surveillance easier, 

cheaper, and consequently more prevalent.20"1 A law enforcement agency's 

gaze is no longer limited by the number of agents available to drive around a 

city, but only by the amount of money available in its budget to pay wireless 

carriers for their assistance, or to purchase GPS tracking devices or other 

similar technologies.20s l'vloreover, although such surveillance is supposed to 

201. Id at Preface. 

202. United States v. Pineda-Moreno, 617 F.3d 1120, 1124 (9th Cir. 2010) (Kozinski,]., 

dissenting from denial of rehearing en hanc). 

203. See Appeal afln tv If/D. Pa. Applimtion, 620 F.3d 304. 317 (3d CiL 2010) (noting that 

"it is unlikely that cell phone customers are aware that their cell phone providers coUect and 

store historical location infomlation"). 

204. See United States v. Garcia, 474 F.3d 994, 998 (7th Cir. 2007) ("The new 

[surveillance] technologies enahle, as the old (because of expense) do not, wholesale 

surveillance .... Technological progress poses a threat to privacy by enabling an extent of 

surveillance that in earlier times would have been prohibitively expensive."). 

205. Christopher Soghoian, An nnd to Pril)(lty Theater: n.'PoJing and DiJaUlrtlging Copomte 

Disc!ostm 0/ User Data to the GOlJen/11Je/?t, 12 MIN],;. JL. SCI. & TECII. 191, 222-23 (2Ull). 

("Many telecommunications companies and ISPs seek and typically receive payment from 

government agencies for the surveillance services they provide, a practice that the law often 

permits."). The cost of location surveillance by some carriers appears to have plummeted 

over the past decade--a savings that they were obligated to pass on to law enforcement, 

though no public data exists for comparison. For example, in 2U03, Nextel communications 

charged $150 per "ping." See NEXTEL, SUBPOE'lA & COURT ORDERS: KEXTEL'S GUIDE FOR 

LAW ENFORCEMENT 6 (2003), miailable at http://info.publicintclligcncc.nct/ncxtclsubpoena. 

pdf. In 2009, it was revealed that law enforcement agencies had perfurmed 8 million pings 
123 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 167 

be invisible, it is becoming more perceptible through media stories, making 

the fact of its pervasive existence known, at least in an abstract sense.206 This 

simultaneous visible and invisible presence of surveillance is precisely what 

produces the anxiety that is the foundation of the panoptic effect. 207 These 

particular location technologies partake of a whole system of surveillance 

instmments and mechanisms, both governmental and private, which 

constmct and project the government's gaze.2U~ 

Echoing the conclusions hinted at by the history of surveillance, its 

coercive utility, and the rapid innovation in contemporary surveillance 

technology, including geolocation systems, Seventh Circuit Judge Flaum, 

while criticizing the reasoning of lvlqyllard in CUelJm"-Perez, suggests that the 

fact of the "goveo1ment's gaze" itselt~ as exerted by "mass use of GPS 

via a website created by Sprint/Nextel. See l'imda-Morel2o, 617 F.3d at 1125 (Kozinski, J., 

dissenting from denial of rehearing en banc). Although "We have no direct evidence to 

suggest that the carrier has reduced the cost of its pings (or moved to a fi.xed fee, rather than 

per-ping charges), even without adjusting for inflation, had Sprint charged $150 for each of 

the 8 million pings, it would have made $1.2 billion. Since law enforcement certainly did not 

spend that much money for this pmpose, some new billing arrangement must have 

motivated the increased activity level. 

206. See ,~emrally The UVir; (HBO cable television sel~es, 2002-2008); see also Anders 

Albrechtslund, SurJ)ezllatice and Tltbics ill Film: Rear \Vindow (mdllw Conversation, 15 J. CRTM. 

TUST. & POPULAR CULTURE, no. 2, 2008, at 129-44. 

" 207. Regarding the "Panoptic effect" of the state's gaze, Professor Daniel So love points 

out that: 

~I\lthough concealed spying is certainly deceptive ... ri1t is the awareness 

that one is being watched that affects one's freedom. A more 

compelling reason why covert surveillance is problematic is that it can still 

have a chilling e ffeer on behavior. Tn fact, there can be a more widespread 

chilling effect when people arc generally aware of the possibility of 

surv-eillance hut are never sure if they are heing watched at any particular 

moment. 

DAN1EL SOLOYE, lJI'-DhKS'J'AND1NG PKlvACY 109 (2008). This is true, unequivocally, 

regarding the specular value of strategically displaying and withholding evidence of state 

power. Moreover, revelations of the covert commercial use of location-based tools, such as 

the recently divulged use of i\pple's iPhone and Google's Android phones in WiFi mapping, 

have the indirect effect of reinforcing the general sense of the state's coercive gaze and its 

power to influence compliance with social nonns, whether or not there is any actual 

convergence of interest between the state and private actors in a given case. See ~A,.ngwin & 

Valentino-Devl~es, slipranote 41. 

208. See Christopher Slobogin, Ts the T'olilth Ameruimerlt RelelYJtlt it! (J TedJrlologim/ Age?, 

bCTURE CONST. (Brookings Inst., Washington, D.c.), Dec. 8,2010, available athttp://,,,,,,",'W. 

hrookings.edu/ ~ /media/Files/ rc/papers/201C1/1208_ 4th_amendmenUlohogin/12C18_ 4th 

_affiendmencslobogin.pdf (describing the negative, real world impacts of surveillance even 

when the government makes no use of the surveillance product). 
124 

168 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

technology," may represent a "constitutional ill" which amounts to a 

cogniL:able harm.209 

Historical location information produced hy mohile devices adds another 

layer of implication to the panoptic effect. Such information is, of course, a 

record of where we have been. These data are stored by companies providing 

wireless services to consumers and on mobile devices for periods of time 

unknown to the user since retention policies vary by company.210 Some 

companies may store more precise data than others,211 but through these data 

the government may get an accurate picture of most everywhere we have 

been. 212 Moreover, once information is disclosed, the government entities 

responsible for the investigation add it to databases and keep it for an 

indet1nite period of time.2D In effect, modern location technology can give 

the govemment an increasingly perfect memory of our activities, thus making 

it impossible to escape one's past. Data retention policy, at this point, might 

he considered a relatively unknown and thus "immature" source of panoptic 

power. We are only now heginning to learn the details and scope of the 

heretofore hidden commercial use of location data on smartphones,214 and 

Congress is currently considering data retention legislation that will require 

providers to store subscriber data for tvvelve months.ll5 These developments 

209. United States v. Cuevas-Perez, 640 F.3d 272, 285 (7th Cir. 2011) (blaum, J, 

concurring} 

210. Soghoian, supra note 205, at 210 ("[1\1]ost technology providers and commlUlications 

carriers now have established data retention policies that govern the length of time before 

which they will delete customer records, communications, logs, and other data. 

Unfortunately, outside of the search engine market, where pressure from European 

regulators has led to companies puhlicly touting their policies, few other finns will puhlicly 

reveal their own data retention rules."). 

211. See Location IIearing, .wpm note 19, at 27 (written statement of Prof. Matt Blaze, 

Univ.ofPa.). 

212. See People v. Weaver, 12 N.Y.3d 433, 441-42 (2009) (describing the types of 

infomlation that tracking devices can record ahout an individual's life). 

213. See J"enerally Fred H. Cate, Govemmetlt Data l'vIininJ": The Needfor a L~f!,al Framework, 43 

IIARv. CR.-CL. L. IlliY. 435 (200S). Moreover, the data of innocent individuals who are not 

targets of government surveillance can get "swept up" by community of interest relluests or 

other compelled disclosures of data that seek to discover everyone who was at or near a 

particular location at a particular time. 

214. See Jennifer Valentino-DeVries & Julia Angwin, Latest Trr:aJtlrr: Is Locatiot! Data, 

WALL ST. J. (May 10, 2(11), http://on.wsj.com/xJGP9u ("Location information is emerging 

as one of the hottest commodities in the tracking industry .... [T]he Journal's '\'I;'11at They 

Know' series found that 47 of the 101 most popular smartphone apps sent location 

lnh)nnatiotl to other ccnnpanles."). 

215. The Protecting Children from Internet Pornographers Act of 2011 was favorably 

reported out of the House Judiciary Committee on July 2S, 2011 and requires certain tyl1es 

of providers to retain some types of data for at least 12 months. See H.R. 1981, 112th Congo 

§ 4 (2011), at'ailable athttp://1.usa.gov/xeBBB6. 
125 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 169 

will inevitably lead to a broader public discussion of both the commercial and 

law enforcement uses of historical location data. These discussions will 

ostensibly be conducted in the name of protecting the public from the 

government's intrusive eye, which will serve ironically to enhance its power 

to reinforce the panoptic effect. 

More than forty years ago, Vice President Hubert Humphrey observed 

that "[wJe act differently if we believe we are being observed. If we can never 

be sure whether or not we are being watched and listened to, all our actions 

will he altered and our very character will change. zl6 Justice Douglas made the 

same point a few years later, observing that "[mJonitoring, if prevalent, 

certainly kills free discourse .... ,,217 IIumphrey and Douglas botl, anticipate 

Foucault in their conclusions in describing the effect of being observed. To 

these men, one of politics, the other of law, the observing gaze of tl1e state 

was, intuitively, a powerfully coercive force that changes people, as surely and 

utterly as the Medusa's gaze was said to change men to stone. 

The ever-improving accuracy of location technology has given the 

government's gaze a degree of clarity hitherto undreamed of~ except perhaps 

in dystopian novels such as Orwell's 1984. Notably, as they contront the 

powerful gaLe of modern surveillance technologies, judges around the 

country are voicing their own anxiety regarding the impact of this technology 

on individuals and society, often turning to sources like Orwell to illustrate 

their conclusions. Tn People 2}. U:7ea2)el~ a case about a GPS tracking device 

placed on a car, Judge Lippman expressed his concern over tl1e very personal 

profile of an individual's life captured by tracking technologies: 

The whole of a person's progress through the world, into bod1 

public and private spatial spheres, can be charted and recorded 

over lengd1Y periods possibly limited only by the need to change 

lie transmitting unit's batteries. Disclosed in the data retrieved 

from d1e transmitting w1it, nearly instantaneously wid1 d1e press of 

a button on d1e highly portable receiving LU1it, will be trips d1e 

indisputably private nature of which talces little imagination to 

conjure: trips to d1e psychiatrist, d1e plastic surgeon, d1e abortion 

clinic, lie AIDS treatment center, d1e s trip club, the criminal 

defense attorney, d1e by-d1e-hour motel, d1e w1ion meeting, d1e 

mosque, synagogue or church, d1e gay bar and on and on. 'X/hat d1e 

technology yields and records wid1 bread1talcing quality and 

quantity is a highly detailed profIle, not simply of where we go, but 

by easy inference, of our associations-political, religious, amicable 

and amorous, to name only a few-and of d1e pattern of our 

216. Hubert H. Hmnphrey, ForeJJ}ord, in EDWARD V. LOl'G, TIlE INTRUDERS, at viii (1967). 

217. United States v. White, 401 U.S. 745, 762 (1971). 
126 

170 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

professional and avocational pursuits. 'W11en multiple GPS devices 

are utilized, even more precisely resolved inferences about our 

activities are possible. ~A.nd, with GPS becoming an increasingly 

routine feature in cars and cell phones, it will be possible to tell 

from the technology with ever increasing precision who we are and 

are not with, when we are and are not with them, and what we do 

and do not carryon our persons-to mention just a few of the 

highly feasible empirical configurations 218 

Likewise, in his dissent in Ul2ited States 2). Pi71eda-Nrorel2o,219 a case where the 

:'-Jinth Circuit rejected en banc review of a panel decision involving GPS 

technology, the ever~witty220 Judge Kozinski turns deadly serious, invoking 

his own childhood in Communist Romania and alluding directly to tlle 

setting of 1984 as he describes the tracking technology in question: 

I dun't think that must peuple in the United States wuuld agree 

with the panel that sumeune whu leaves his car parked in his 

driveway outside the door of his home invites people to crawl 

lUlder it and attach a device that will track the vehicle's every 

movement and transmit that information to total stf<Ulgers. There 

is something creepy and whllunerican about such clandestine and 

wlderharlded behavior. To those of us who have lived wIder a 

totalitariarl regime, there is arl eerie feeling of deja vu. This case, if 

arly, deserves the comprehensive, mature arId diverse consideration 

that arl en barlC parlel GUl provide. We are taking a giarlt leap into 

the unknown, arId the consequences for ourselves ,Uld our children 

may be dire arId irreversible. Some day, soon, we may wake up arId 

fmd we're living in Ocearlia221 

218. People v. Weaver, 12 'lY.3d 433, 441-42 ('.1ay 12, 2009). 

219. United States v. Pineda-Moreno, 617 fi.3d 1120, 1121-26 (9th Gr. 2010) (Kozimki, 

]., dissenting from denial of rehearing en bane). 

220. In criticizing the underlying panel's conclusion that the defendant has no 

e"'Pectation of privacy in his driveway,Judge Kozinsb e"'Plains: 

The panel authorizes police to do not only what invited strangers could, 

but also uninvited children-in this case crawl under the car to retrieve a 

ball and tinker with the undercarriage. But there's no limit to what 

neighhorhood kids will do, given half a chance: They'll jump the fence, 

crawl lUlder the porch, pick fruit from the trees, set fire to the cat and 

micturate on the azaleas. To say the police may do on your property what 

urchins might do spells the end of Fourth Amendment protections for 

most people's curtilage. 

Ttl at 1123. 

221. Id. at 1126. Further, the court in United States v. Sparks refused to find a Fourth 

Amendment violation in the govemment's use of GPS placed on the defendant's vehicle 

under the specific facts of the case, but it nonetheless acknowledged that the court "is not 

unsympathetic to the sentiment expressed by Chief Justice Kozinski and his "linth Circuit 
127 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 171 

Judge Kozinski's language echoes the disturbing uncertainty that results 

when the instruments of the state's panoptic gaLe become even partially 

visible. Indeed, as we have discussed, the very partial nature of their visibility 

is essential to produce the uncertainty and anxiety of the panoptic effect. In 

response, Judge K07inski appeals to a locus of greater authority, here an en 

banc panel of the Ninth Circuit, to assert the control (i.e., "comprehensive, 

mature and diverse consideration") necessary to govern dle state's panoptic 

ga:Le in the name of preserving dIe specifically "American" way of life it 

seems to threaten. 

Judge Flaum, in his concurring opinion in goes further still, 

suggesting the government's increasingly powerful and clear sense of sight 

widl regard to me lives of individuals, using new, more accurate location 

technologies, might offend the Fourth Amendment in a manner explicitly 

proscribed by the Founders as it was being crafted: 

There may be a colorable argument ... that the use of GPS 

technology to engage in long-term tracking is analogous to general 

warrants that the Fourth A.mendment was designed to curtail, 

because of the technology's potential to be used arbitrarily or 

because it may alter the relationship between citi:Len and 

government in a way that is inimical to democratic society222 

hrethren, that there is something 'creepy' ahout continuous surveillance hy the government." 

750 F Supp. 2d 384, 395-96 (D. Mass. 2010). Ylihile noting that "[aJdvances in teclUlology, 

like CPS devices, provide neutral and credible evidence and thus facilitate the ultimate (and 

yet am0'l"hous) gual of 'Justice,' " the court also recogl1izes that "it is easy to envision the 

worst-case Orwellian society, where all citizens are monitored by the Big Brother 

government." Id. at 394-9\ Jee airo In I~ Application of the U.S. Authorizing the Release of 

Historic Cell-Site Info., 809 F Supp. 2d 113, 127 (ED.NY. 2011) ("Vihile the government's 

monitoring of our thoughts may be the archetypical Orwellian intlUsion, the government's 

surveillance of our movements over a considerahle time period through new technologies, 

such as the collection of cell-site-location records, without the protection of the Fourth 

Amendment, puts our county far closer to Oceania than our Constitution permits."). 

222. United States v. Cuevas-Perez, 640 F3d 272, 285 (7th Cir. 2011) (Flaum, J, 

concurring). In the same case, in her dissent, Judge Wood also appeals to Orwell for 

inte'l,retive authority, with a sense of urgency matching that of Judges Flaum and Kozinski: 

This case presents a critically important question about the government's 

ability constantly to monitor a person's movements, on and off the public 

streets, for an open-ended period of time. The technological devices 

availahle for mch monitoring have rapidly attained a degree of accuracy 

that would have been unimaginable to an earher generation. They make 

the system that George Orwell depicted in his famous novel, 1984, seem 

clmusy and easily avoidable by comparison. 

Id. at 286 (\Vood, j., dissenting). 
128 

172 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

Judge Flaum's concurrence strongly criticizes the reasoning of the lVlaplani 

court223 (the case concluding that Ul1ited States' fl. K110th 224 does not govern 

prolonged GPS surveillance and instead applying a mosaic theory of the 

Fourth Amendment), yet he seems to go out of his way to propose an 

alternative theory of the Fourth ;\mendment that might, perhaps, offer a way 

to cabin or control the government's prolonged use of GPS tracking. This 

palpable concern on d1e part of senior jurists from two appellate courts is 

indicative of the general harm to society, to which all others are ancillary, 

created by location technology, and the issues this technology raises should 

he scrutinized accordin8ly. 

But where should one turn for sufficient authority? A Ninth Circuit en 

banc panel? How about the ultimate authority in the judicial branch: the 

Supreme Court of the United States? Judge Flaum considers that option 

briefly, perhaps aware of the government's petition for certiorari in lvlqJ11afd, 

later granted in jotze.r,225 in further reducing his argument to its hare hones: 

"on this view, the constitutional ill of prolonged or mass use of GPS 

technology would not necessarily be based on the information acquired by 

the device but on the fact of the government's gaze.,,226 

It may be tempting, as a judge on a federal appellate court, to urge the 

Supreme Court to employ the Fourth Amendment against the "ill" that can 

he inflicted hy the mere "fact of the government's gaze." But Judge Flaum 

himselt~ having indulged in the Fourth !\mendment argument and perhaps 

gauging the limited power of the judiciary to use the common law in an 

effort to assert control of technology changing at d1e pace of :'vIoore's Law,227 

immediately withdraws it in favor of a legislative remedy: 

223. Id at 2Sn (flaum, J., concurring) ("Neither of lVIaynard's twin hases for ruling that 

the defendant had an objectively reasonable expectation of privacy is doctrinally sound---or 

all that workable as a practical matter."). 

224. 4(,0 U.S. 276 (1983) 010lding that a person does not have a reasonable expectation 

of privacy in movements from one place to another on public thoroughfares). 

225. See Petition for Writ of Certiorari, Cnited States 'i. Jones, 132 S. Ct. 945 (2012) 

(No. 10-1259). 

226. Cuevas-Pmz, 640 F.3d at 285 (7th Cir. 2(11) (bIaum,J, concurring). 

227. Moore's law desctihes a long-tenn trend in the development of computer 

hardware, specifically that the number of transistors that can be placed inexpensively on an 

integrated circuit doubles approximately ev-ery two years, resulting in a corresponding, 

roughly exponential, increase in the capabilities of many digital devices-processors, 

computer memory, digital camera resolution, and more. Moore's projected rate of growth, 

which is used in the semiconductor industry to guide long-term planning and to set targets 

for research and development, has continued for over fifty years and is expected to remain 

constant through at least 2015 or later. It was named for Gordon E. Moore, the co-founder 

of Intel, who described the trend in a 1965 paper. Gorden E. Moore, Afore 

CompotletltJ onto Itlt~graled CirCliits, 38 ELOCl'RON1CS, no. 8, Apr. 19, 1965, at 
129 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 

Of course, the Supreme Court just last term reminded us dlat 

"rtlhe judiciary risks error by elaborating too fully on the Fourdl 

A.mendment implications of emerging technology before its role in 

society has become clear." Cify of On/an'o 1) • • Quon, 130 S. Ct. 2619, 

2629 (2010). In light of Klloll's holding and QlIOIl'S admonition, it 

strikes me not so much as insufficiently circumspect as simply 

beyond our mandate to conclude dlat what is permissible when 

accomplished witll a beeper is impermissible when accomplished 

widl a GPS unit. I agree widl dIe dissent, however, dlat notlling 

would preclude Congress from taking dIe important questions 

implicated by GPS technology and imposing answers. Indeed, tile 

unsellled, evolving expecLalions in lhis realm, combined wilh lhe 

fast pace of technological change, may make the legislature tile 

branch of government dlat is best suited, and best situated, to act22~ 

173 

The Supreme Court has now decided JoJZeJ'. "There do we find ourselves? 

The concurring opinions echo the concerns Judge K07.inski and Judge Flaum 

expressed. Justice Alito's concurrence recognizes that law enforcement's 

secret, long-term monitoring of every single movement of an individual's car 

does not accord with society's reasonable expectations of privacy.229 Justice 

Sotomayor even quotes Judge Flaum's concurrence in Cttevas-Perez as she 

asserts: "GPS monitoring-hy making availahle at a relatively low cost such a 

substantial quantum of intimate information about any person whom the 

Government, in its unfettered discretion, chooses to track-may 'alter the 

relationship between citizen and govemment in a way that is inimical to 

democratic society.' ,,230 

The majority opinion, however, functions only to limit the scope of the 

"government's ga7,e" with respect to the physical attachment and use of a 

GPS tracking device. 1ndeed, the majority's definition of "search" does not 

apply to situations where tile transmission of radio or other electronic signals 

is not attained through the government's physical attachment of a device by 

trespass. Moreover, Justice Alito's adoption of a mosaic-type theory raises 

http://download.intel.com/museurn/ Moores_Law / Articles-Press_releases/ Gordon_Moore_ 

19G5_,'\rticle.pdf. See generally Dob Schaner, TIle Denchmark of Progress in Semiconductor 

Electronics (Sept. 26, 1996) (unpublished paper), available at http://research.microsoft.com/ 

en-us/urn/ people/ gray/Moore_Law.html. 

228. Cl1eliaJ-Pmz, 640 F.3d at 285-86 (Flamil, J., concurring) (citing Orin S. Kerr, The 

FOl1rth Amendment and New Technologies: COllstitl1tiollal Nyths and the Case for Calltion, 102 MICH. 

L REV. 801, 805-06 (2004) (arguing that G:mgress should be the primary driver of privacy 

protections when technology "is in flux"». 

229. joneJ, 132 S. O. at 964 (jllito, J., concurring). 

230. Id at 956 (Sotomayor, J., concun~ng) (quoting ClJel'as-Perez, 640 F.3d at 285) 

(1llaum,J., concurring)). 
130 

174 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

the same thomy line drawing issues presented by l'vlaptard. 231 Perhaps 

recogni:oing the limitations of this approach, Justice Alito acknowledges that 

"[tJhe best we can do in this case is to apply existing Fourth Amendment 

doctrine and to ask whether the use of CPS tracking in a particular case 

involved a degree of intmsion that a reasonable person would not have 

anticipated."232 But like Judge Flaum, Justice ~A.lito recognizes that "[iJn 

circumstances involving dramatic technological change, the best solution to 

privacy concerns may be legislative.,,233 

Certain judges and justices who have closely considered the implications 

of location technology have expressed concern, even anxiety, over the effects 

on society of the government's use of location technologies. Some of these 

jurists have further questioned the law's current ability to contain its effects 

and have found that ability, and hence their own powers, wanting. We share 

the jurists' skepticism. Cogni:oant of the power of the government's ga:oe and 

in agreement with Justice Alito's234 and Judge Flaum's conclusion that the 

legislature is likely the hranch of government hest suited to fashion the 

appropriate protections against this ga7:e, we now present our model privacy 

framework for location information. 

VI. LEGISLATIVE PROPOSAL 

In an effort to try and hridge the gap he1\veen the currently polarized 

positions of privacy advocates and law enforcement, we offer a model 

privacy framework to govern law enforcement compelled disclosures of 

historical and prospective location information.l3s It is neither the most 

231. See Jt/pm Section m.B.2.b. 

232. JoneJ, 132 S. O. at 964 UlJito,J., concurring). [iurthermore, during the gov~ernment's 

oral argument in JONes, shortly following Justice Breyer's stated concenl over "what. a 

democratic society lwouldJ look like if a large number of people did think that the 

govemment was tracking their every movement over long periods of time" and his searell 

for a "reason and principle" that would "reject" this kind of government surveillance "but 

wouldn't also reject igovernment tracking! 24 hours a day for 2il days," Justice Scalia 

exclaimed, "Don't we have any legislatures out there that could stop this stuff?" Transcript 

of Oral ~I\rgument at 24-26, JOIleS, 132 S. Ct. 945 (2012) (No. 1O~1259), available at http:/ / 

www.supremecourt.gov/oral_arguments/argument_transcripts /1 O~~1259.pd f 

233. Id. (citing Kerr, Jtipmnote 228, at 805--(6). 

234. Justice Ginshurg, Justice Breyer, and Justice Kagan all signed Justice Alito's 

concurrence regarding this conclusion. 

235. \Ve intend the privacy framework and access standards proposed in this Part only 

to apply to criminal law enforcement authorities. They are not intended to amend or affect 

intelligence or national security authorities that the government may use to acquire location 

infonnation. The govemment's use of such intelligence tools is heyond the scope of this 

Article. Any actual legislation that seeks only to amend criminal law enforcement authorities 

would include appropriate statutory language to exempt relevant intelligence authorities. 
131 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 175 

friendly to law enforcement nor the most protective of privacy, but it is an 

attempt to find a reasonable balance among the interests of law enforcement, 

privacy, and industry. 

Our proposal relies on several overarching principles that form a 

foundation for crafting the correct balance: a strong privacy framework that 

does not unduly limit law enforcement investigative activities or negatively 

affect industry innovation. These principles are influenced by a variety of 

sources including, but not limited to, ideas expressed by the DDP Coalition, 

otl-the-record discussions with industry representatives, information revealed 

in public congressional hearings and elsewhere in the public record, and 

extensive discussions with private practitioners, academics, and privacy 

advocates. 

1\. OvER ARCHING PRINCIPLES 

1. Clear Rules 

Law enforcement, judges, and industry all benefit from clear access 

standards.236 \x;11en the ECPA was passed in 1986, location data was not a 

"routine tool" used by law enforcement and cell phones were a luxury 

affordable to only a small number of people. Congress, understandably, did 

not have the clairvoyance to foresee the explosion in wireless mohile devices. 

'.Jor did Congress anticipate the confusion237 that would ensue due to the 

lack of any clear guidance in the ECP A in the form of standards goveming 

law enforcement compelled disclosures for prospective location infonnation. 

In contrast to the uncertain, even chaotic, legal landscape that currently 

hurdens the analysis of law enforcement access to location data, clear 

standards enable all stakeholders to execute their respective responsibilities 

certain in the knowledge that tl1ey are following the law. lior prosecutors and 

agents, this means they can eHiciently get access to location information 

because they won't have to "haggle" over tlle appropriate standard for access 

\viili certain judges. For mabristrate judges, clear standards better enable iliem 

to ensure that the government follows the law in obtaining access to any 

location data. Moreover, industry can comply with the law without omning 

236. See Comments of CTIA-The \Vireless Association, supra note 46, at 16 ("The lack 

of a consistent legal standard for tracking a user's location has made it difficult for carriers to 

comply with location demands."); Senate Judiciary 2011 RePA Heming, Jupm note 7, at 7 

(testimony of lames A. Baker, Assoc. Deputy Attorney Gen., U.S. Dep't of Justice); Location 

Hearing, .rupra note 19, at 85 (written statement of Judge Stephen \Vm. Smith, C.S. Magistrate 

Judge). 

237. See Jupra Part III. 
132 

176 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

the current risk of incurring liability for inappropriately disclosing customer 

infommtion to the govemment.238 

2. Techllolqgy Neutrality 

In order for the ECPA to remain a "fof\vard looking statute,,,2,0 even 

with respect to the next generation of smartphones, it is critical that law 

enforcement access standards do not depend on the precision and 

capabilities of particular location technologies, or with the general state of the 

industry at the time of drafting. There has been an explosion in the growth of 

location-based services over the past several years. During that time, the 

precIsion of the location information these technologies produce has 

increased dramatically, such that single cell tower data-particularly where 

enhanced by some of the 350,000 femtocells deployed around the 

COl.l11try24U_is becoming as accurate as GPS.241 Indeed, the rapid pace of 

innovation, driven by market incentives to enhance the accuracy of locationbased advertising, suggests that location information will continue to become 

increasingly precise. 

/\. standard that is dependent on the precision of the location data 

requested creates an unstable, unworkable situation where, for example, 

certain magistrate judges feel compelled to examine deployment maps of cell 

towers or seek expert guidance to determine the precision of the location 

data produced in a particular district. 242 To foster clear rules that can be 

applied without undue confusion, ultimately leading to greater stahility in the 

law, Congress should enact law enforcement access standards that are not 

dependent on the specific precision of location data. 

3. Standardr Alone U7i!1 Not A cbieve the Appropriate Balance 

Most of the privacy community's location information advocacy to date 

has focused on a "high" standard for law enforcement access. This focus has 

led to a stalemate with much of the law enforcement community and has put 

powerful members of Congress "on guard" to protect law enforcement 

equities. Regardless of the standard required for law enforcement access to 

238. See getJertllly Albert Gic1ari, Jr., Companies GlUgbf in tbe Middle, 41 U.S.F T ,. REV. 535 

(2007). 

239. See IIow'e Judiciary 2010 ECPA Reform IIeming, ,rupm note IS, at 10 (written statement 

of James X. Dempsey, Vice President of Pub. Policy, etr. for Democracy & Tech.). 

240. See Press Release, lnforma Telecoms & Media, supmnote 27. 

241. See Tn r~ 2010 SJ) Tex. AppIL'ation, 747 F Supp. 2c1 827,834 (S.D. Tex. 2010) ("/\s 

cellular network technology evolves, the traditional distinction between 'high accuracy' CPS 

tracking and 'low accuracy' cell site tracking is increasingly ohsolete, and will soon he 

effectively meaningless."); see also supra Section lLF. 

242. See supm Sections IILA.2, III.A.3. 
133 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 177 

location data, there are some privacy concerns that can only be addressed 

through post collection process and rules, such as data minimiL:ation, 

subscriber notification, and statistical reporting. A regime of reasonable 

access standards comhined with downstream privacy protections seems to 

present the best way forward. 

4. ItIJ'istence on a Single Location Standard Is a '~1 Foolish ConsiJ'tenry"243 

As stated in the Introduction, this proposal is not the most privacy 

protective, the least burdensome to industry, or the most law enforcement 

friendly. Rather, it is an attempt to eliminate the uncertainty and instability 

currently plaguing the law and to achieve a halance of equities that is more 

palatable insofar as it improves the positions of each of these stakeholders in 

some appreciable way. The process of passing legislation is largely about 

compromise. As a result, the "right" and politically feasible policy balance 

may not always create a perfectly "consistent" set of law enforcement access 

standards or privacy protections, if consistency is to be read as mere verbal 

or structural symmetry for its own sake. 

Some privacy scholars have argued that the law, as a matter of policy, 

should treat historical and prospective location data the same, specifically 

calling for a justification for treating them anytl1ing otl1er than tl1e same. 244 

Such an approach, however, would be a significant departure from existing 

statutory surveillance law, which has traditionally treated historical (stored) 

and prospective (real time) information differently, requiring more process 

when the government compels real time information. 245 Insistence upon a 

243. "A foolish consistency is the hobgoblin of little minds, adored by little statesmen 

and philosophers and divines." Ralph Waldo Emerson, SelfReliatlce, itl 2 THE COLLhC'J'ED 

WORKS OF RALPH W. EMERSON: ESSAYS: FIRST SERIES 33 Goseph Slater et a1. eds., 1979) 

(1841). 

244. i\t the 20"11 Privacy Law Scholars Conference, co-sponsored by the law schools at 

the University of California, Berkeley and The George Washington Cniversity, the authors 

workshopped a draft of this Article. Several privacy scholars and members of the privacy 

commlmity lluestioned our justification for treating stored location information differently 

from real time location data, advocating for a standard that would require a warrant for all 

location data. 

245. bor example, the government can use a subpoena to obtain stored telephone toll 

records, see IS lI.s.e. § 2703 (c) (2) (2010), hut must get a Pen/Trap order from a court to 

obtain the same information in real time, Jee iei. § 3121. In order to obtain the content of 

e-mails in real time, tlle government must meet higher hurdles of a wiretap "super" warrant, 

which requires a court to find that "no11nal investigative procedures have been tried and 

have failed or reasonably appear to be unlikely to succeed if tried or to be too dangerous," id. 

§ 25IS(c), in addition to several other "prohahle cause" requirements, .fee id § 2S1S (a)-(h), (d). 

On the other hand, the government can get stored e-mail content by meeting the standard 

Rule 41 "probable cause" showing, or less. See § 2703(a)-(b); see aim Location IIealill/", supra 
134 

178 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

standard that is "consistent" in the sense only of being identically applied to 

this distinction would serve only to polariL:e the legislative process to the 

point of collapse. Law enforcement will predictably retreat to one comer in 

order to demonstrate how a prohahle cause standard for all location data 

would unduly limit investigative activities 246 while privacy advocates will just 

as predictably withdraw support for any legislation that authorizes law 

enforcement to compel all location information with a unitary standard lower 

than probable cause. Empathy is lost. Synthesis is precluded. This familiar 

impasse, which has become the norm in our recent political life, is here the 

fruit of a foolish consistency that would level a long-held distinction hetween 

two categories of data and, in doing so, likely derail a legislative balancing 

process that could improve the position of all stakeholders when measured 

against the current state of the law. 

As a matter of legislative strategy then, mandating a single standard for the 

sake of this leveling form of consistency has risks. Such consistency can, of 

course, cut hoth ways: it would he equally consistent to allow law enforcement 

access to all location data with either a probable cause warrant or a D Order. 

Indeed, consistency for its own sake, argued in either direction, is a reductive, 

polarizing position that short-circuits any legislative etlort to harmonize the 

competing policy interests of the privacy and law enforcement communities. 

B. How To DEFINE LOCA'l"IO'J INFORMAllO~ tOR PURPOSES OF 

AMENDIKG THE ECPA 

There are many data forms that reveal an individual's location and that 

law enforcement can compel from third-party providers. These sources 

include wireless phone carriers and smartphone platform vendors (such as 

Apple and Google). Location information can also be discerned through 

transactional records, such as tollbooth, public transport, and credit card 

records.247 Law enforcement agencies can also ohtain location information 

directly, without going to third parties, by intercepting wireless phone signals 

note 19, at 82 (written statement of Judge Stephen Wm. Smith) (explaining levels of privacy 

protection given to different surveillance authorities). 

246. See .rllpra Section IV.B. 

247. See Ryan Singe!, FedJ 1I7 arranfteJ:lq Tracking AmericanJ' Lrrdll CardJ if! Real Time, 

WlliliD (Dec. 2,2010), http://www.wired.com/threatlevel/2010/12/realtime/ ("Federal law 

enh:>rcement agencies have been tracking Americans in real-time using credit cards, loyalty 

cards and travel reservations without getting a court order, a new document released under a 

government mmhine request shows .... [S]o-called 'Hotwatch' orders allow for real-time 

tracking of individuals in a criminal investigation via credit card companies, rental car 

agencies, calling cards, and even grocery store loyalty programs."). 
135 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 179 

using a Triggertlsh, Stingray, or other similar tracking technologies,248 or by 

covertly installing a GPS tracking device under a car. \Vhile law 

enforcement's access to these sources of data all raise legitimate privacy 

concerns, this }\rticle focuses on the compelled disclosure of location 

information from communications carriers, such as mobile phone services. 

Congress can, and should, look into other forms of location surveillance, but 

they remain beyond the scope of dlis Article. Our proposed standard, 

directed at third-party communication carriers, begins with the following 

statutory definitions: 

An "electronic location service" CELS") is any service which possesses 

location information about a customer, subscriber, or user. 

"Location information" ("LI'') is any information derived or otherwise 

calculated from tile transmission or reception of a radio signal tint reveals 

tile approximate or actual geographic location of a customer, subscriber, or 

user 249 

"Historical location information" is location information that existed prior 

to the issuance of an order. 

"Current or prospective location information" is location information dlat 

comes into existence after a court order for disclosure of that information is 

issued. 

248. Lell J-ite Simlilators, '1 ~ggedish, cell Pholles (last updated Feb, 23, 2007), ill U.S. Dep't 

of Justice, Response to Freedom of Tnfonnation Act Request No. 07-4130 reo Mobile Phone 

Tracking 18 (Aug. 12, 2008), available at http://www,aclu,org/pdfs/freespeech/cellfoia_ 

releaseJI74130_20080812,pdf (stating that Triggerfish can he deployed "without the user 

knowing about it, and without involving the cell phone provider"); Julian Sanchez, FOu1 

Doc.r Sho]J/ Pedr C:m Lojack AiobileJ Withollt Telco IIelp, ARS T12CHN1CA (Nov. 16, 2008), 

http:// arsteciullGLeom/teeh-pohey /nelN s/ 2008/ 11/ foia-does-show-feds-GUl-lojaek-mobileswithout-telco-help.ars ("The Justice Department's electronic surveillance manual explicitly 

suggests that triggerfish may be used to avoid restrictions in statutes like CALEA that bar 

the use of pen register or trap-and-trace devices-which allow tracking of incoming and 

outgoing ca11s from a phone subject to much less stringent evidentiary standards-to gather 

location data,"); Jee also Jennifer Valentino-DeVries, 'Stingrqy' Phone Tracker Fl/eLf Constitutional 

Clash, WALL ST. J (Sept. 22, 2011), http:/ / on,wsj.com/ lhMb7d. 

249. "Radio" refers to the radio frequency ("RF") portion of the electromagnetic 

spectmm, which is "generally defined as that part of the spectrum where electromagnetic 

waves have frequencies in the range of ahout 3 kilohertz [3000 hertz] to 300 gigahertz." liED. 

CO>IMC''1S COMM'N, Bl~LLETIN No, 56, QUESTIONS AND ANSWERS ABOUT BIOLOGICAL 

EFFECt'S A'ID POThNT1AL HAZAKDS OF ILA,D10FIlliC,2UI2NCY ELECTKOJl;u\GNI2T1C Fll2LDS 2-3 

(4th eel., 1999), (Jl)"ilaUe at http://www.fcc.gov /Rureaus/Fngineerin~ Technology/Documents/ 

bu11etins/ oet56/ oet56e4,pdf, see also Radio, MCRRLA,M-WEDSTCR DICTIONARY Ol'LINE, http:/ / 

www.tllen~amwebster.com/dictionary/radio (last visited Mar. 19, 2012) (defining radio as 

"of or relating to electric currents or phenomena (as electromagnetic radiation) of 

frequencies between about 3000 hertz and 300 gigahertz"). 
136 

180 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

C. A STAKDARD FOR LAW ENFORCE'>1EKT CO'>1PELLED DISCLOSURES 

OF HISTORICAL LOCATION DATA 

Our proposed law enforcement access standard for historical location 

infonnation is built around the current D Order standard with the addition 

of an element specifically requiring courts to examine whether the scope of 

the reyuest is reasonable in light of the criminal activity being investigated. 

\Ve have previously discussed certain examples of scope permutations in 

investigations 2SO-it would be useless to try and define all of them in 

advance. A discussion of how Congress generally views the scope inquiry 

could also be developed in legislative history. A court, when applying the 

standard, will focus the scope of its inquiry on issues raised (and perhaps 

resolved) by the specific facts presented by the government in its application 

for a D Order. This standard could he drafted as follows: 

(a) DISCLOSURE UPOK COURT ORDER.-Except as provided in 

paragraph (3), a provider of an electronic location service shall provide 

historical location information to a governmental entity only if the 

governmental entity obtains a court order issued by any court of competent 

1urisdiction establishing-

(1) specific and articulable facts showing that there are reasonable 

grounds to believe that d1e location information requested is relevant and 

material to an ongoing criminal investigation; and 

(2) specific and articulahle hcts showing that a reasonahle and sufficient 

nexus exists hetween the alleged or suspected criminal activity descrihed 

in paragraph (1) and the scope of the location data requested. 

(3) PE&vlITTED DISCLOSURES \>:TITHOUT COCRT ORDER.-A 

provider of an electronic location service may disclose historical location 

information with-

(A) d1e express consent of d1e customer, subscriber, or d1e user of d1e 

equipment concerned; or 

(B) as otherwise authorized in lH usc. § 2702 (c) (3)-(Ci). 

Dy maintaining the "relevant and material" language, our standard preserves 

law enforcement eyuities while limiting the unnecessary over-collection of 

historical location information hy requiring courts specifically to approve the 

scope of a request. :Moreover, this standard "forces" the government to 

articulate how the scope of the request is reasonable in light of the particular 

250. See supra Section IILC.1. 
137 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 181 

facts and needs of the investigation.251 \Ve hope that this type of balancing 

can foster a compromise between privacy advocates and law enforcement 

insofar as it docs not raise the historical data access standard up to probable 

cause that would unduly limit law enforcement in the early stages of an 

investigation, but it does require written justification and court approval for 

the scope of the request. 

This standard also maintains the exceptions for disclosure of non-content 

records already present in the ECPA, including emergencies involving danger 

of death or serious physical injury.2s2 Finally, this proposed language clearly 

establishes the standard the government must meet before obtaining access 

to historical location data, a change that benet its all stakeholders. 

D. A STAKDARD FOR LAW ENFORCEYIEKT COYIPELLED DISCLOSURES 

OF PROSPECTIVE LOCATION DATA 

Our proposed standard for prospective location information requires a 

prohahle cause showing. \Ve expand the categories of that showing, however, 

to accommodate common, legitimate law enforcement uses of prospective 

location data, including location information pertaining to a person who has 

committed, is committing, or is about to commit a felony offense or is a 

victim of that offense. 

The DO] has acknowledged that, as a matter of policy, it already advises 

prosecutors and agents to ohtain a prohahle cause warrant for GPS or 

similarly precise location information. 253 Our standard not only codifies the 

DOJ's existing practice regarding GPS and similarly precise location data but 

also requires a probable cause showing (based on the expanded categories) 

for all prospective location data. Insofar as single cell site data can now be as 

precise as GPS location information-and such precision will only continue 

to increase over time-drawing distinctions in the law hased upon data 

precision is no longer logical or workable.254 

2S1. Indeed, in Stephanie's experience as a federal prmecutor, when a standard calls for 

this type of explanation, prosecutors and agents are much more likely to tailor applications 

narrowly at the outset, in anticipation of court scrutiny. 

252. One of the current ECPA exceptions,18 U.s.c. § 2702(c)(6) (2010), puts no limits 

on providers sha11ng non-content inf01mation with third parties who arc not law 

enforcement. In recent testimony, the DOJ has suggested that it may he appropriate for 

Congress to consider restricting disclosures of personal information by service providers. See 

SeI2ate Judiciary 2011 ECPA HearinJ;, JUpra note 7, at 10 (testimony of James A. Baker, Assoc. 

Deputy Attomey Gen., U.S. Dep't of Justice). Insofar as this i\rtic1e focuses on law 

enforcement access issues, it is beyond the scope of this Article to address this issue. 

2S3. See Senate Judiciary 2011 BaA Hearing, .rupranote 7, at 7 (testimony of James A. Baker). 

254. See supra Sections IILA.1, IILB.1, IILC.1, IYB; see also Location Healing, sl1pra note 

19, at 85 (written statement of Judge Stephen Wm. Smith). 
138 

182 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

\Vith the expansion of the categories of probable cause, we have once 

again attempted to accommodate law enforcement investigative needs255 in 

order to foster a compromise between law enforcement and privacy 

advocates. This st311dard could he drafted as follows: 

(1) DISCLOSURE UPON COURT ORDER FOR A PERIOD NOT TO 

EXCEED 30 DIIYS.-Except as provided in paragraph (2), a provider of 

an electronic location service shall provide a governmental entity current or 

prospective location information about a customer, subscriber, or user only 

if the governmental entity obtains a court order from any court of 

competent jurisdiction issued upon a finding that there is probable cause to 

believe that-

(A) the information sought is evidence of a crime: or 

(R) a person is committing, has committed, or is about to commit a 

felony offense or is a victim of that offense; and the location information 

sought to be obtained concerns the location of the person believed to 

have committed, be committing, or be about to commit that offense or a 

victim of that offense. 

(2) PEMlITTED DISCLOSURES \'I,IJ:THOUT COURT ORDER.-A 

provider of an electronic location service may provide the information 

described in paragraph (1)-

(A) to a public safety answering point, emergency medical service provider 

or emergency dispatch provider, public safety, fire service or law 

enforcement official, or hospital emergency or trauma care facility, in 

order to respond to d1e user's call for emergency services; 

(B) with the express consent of the customer, subscriber, or the user of 

the equipment concerned; or 

(C) as otherwise authorized in 18 C.S.c. § 2702(c)(3)-(6). 

(3) DEFINITION.-The term "public safety answering point" means a 

facility d1at has been designated to receive emergency calls and route them 

to emergency selvice personnel. 

(4) EXTJ:<:NSIONS.-Extensions of such an order may be granted for up 

to 30 days upon a prohahle cause showing as detmed in sections (A)-(B) of 

paragraph (1) of this provision. 

This statutory language is not from the ECPA refonn hearings of 2010-

2011. 256 Rather, it is adopted from a bill, entitled me "Electronic 

Communications Privacy Act of 2000," reported out favorahly hy a 

255. See supra Section III. C. 

256. See discussion supra Parts I, IV. 
139 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 183 

Republican-controlled House Judiciary Committee. The bill never became 

law, but it applied the "expanded" probable cause standard to prospective 

location information. 257 These expanded probable cause standards address 

situations ,;vhere, for example, law enforcement may have prohahle cause to 

believe someone has committed a crime yet the suspect's current or 

prospective location information may not itselfbe evidence of a crime.2ss 

Consistent with other real-time surveillance authorities like Pen/Trap and 

the Wiretap Act, our proposal affords prospective location information a 

higher degree of privacy protection than that given to previously stored 

information. 2s9 /\lso mirroring the \\!iretap /\ct,2('0 our proposal places a time 

limit of thirty days for each individual order, without preventing the 

government from returning to a court for an extension. This standard also 

includes specific exceptions to allow for the operation of the E-911 system261 

while incorporating all of the exceptions for non-content infonnation already 

present in the ECPA. Finally, this proposed language clearly estahlishes a 

standard the government must meet hefore getting access to prospective 

location data, a change that again benefits all stakeholders. 

E. POST ACCESS RCLES AND "DOWNSTREAM" PRIVACY PROTECTIOKS 

It is obviously important for Congress to select the right legal standard 

required for law enforcement to obtain location data. Equally important to 

an overall privacy framework, however, are rules regarding the retention of 

the data once it is acquired, notice to individuals "vhose information has heen 

acquired by law enforcement, and reporting requirements to Congress.262 

Indeed, such "downstream" protections can offset any over-collection of 

infonnation by la\v enforcement during the course of an investigation. This 

Section proposes three specific methods to protect privacy following the 

257. See HR. 5018, 106th Congo § 6(a) (2000). 

258. SeeJupm Section 111. C. 2. 

259. See discussion .rttpm note 245 and accompan)ring text. 

260. 18 U.s.c. § 2518(5) (20liJ). 

261. Location IIeating, .wpm note 19, at 36 (statement of '\1ichael Am arm a, Sr. Vice 

President for Public Affairs, TmePosition Inc.) (describing the FCC E-911 relluirement). 

262. See 01ID S. Kerr, UJe ResmitionJ and tbe Futttre o/Sun'eiiiallce Lau), FUTURE CO!-.ST. 

(Brookings Tnst., Washington, D.c.), Apr. 19, 2011, aVai/aUe at http://www.brookings.edu/ 

papers/2011/0419_surveillance_laws_kerr.aspx ("l'fJhe law should still regulate the collection 

of evidence. Dut surveillance law shouldn't end there. The shift to computerization requires 

renewed attention on regulating the use and disclosure of information, not Just its 

collection.") . 
140 

184 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

disclosure of location infonnation to law enforcement: minimization, 

notitlcation, and congressional oversight through statistical reporting.263 

1. lvIi nimization 

Given the large amount of data that law enforcement agencies now 

obtain via location requests and the number of innocent people whose 

infonnation may be obtained through community of interest requests or 

requests associated with a specitlc place, we believe that minimization rules 

can and should playa role in limiting the privacy harms associated with such 

data collection. These minimi:cation rules would focus on removing irrelevant 

location data from law enforcement datahases at a time appropriate to the 

particular investigation or case. Minimi7ation requirements are not a new 

idea. They already playa privacy protective role in several other surveillance 

statutes, including the \Viretap Act,264 the USA PATRIOT Improvement and 

Reauthorization Act of 2005 ("PATRIOT Act"),265 and the Foreign 

Intelligence Surveillance Act ("FISA'').266 

Although Congress has frequently enacted minimization requirements, it 

has never legislated the specific details of how such minimi7ation would 

work with respect to particular surveillance authorities or investigations. In 

both the Wiretap Act and FISA, govemment lawyers submit minimization 

protocols as part of their applications, which are then approved by a judge 

and included in the court order. Likewise, in the PATRIOT Act, Congress 

directed the DOJ to adopt specitlc minimization procedures for records 

263. There are other types of downstream privacv protections that could and perhaps 

should eventually he included in a privacy framework--e.g., the umealing of court orders 

with appropriate redactions at a time when such unsealing would no longer Jeopardize an 

investigation or place individuals involved in it at risk. See, e.g., Stephen \\1m. Smith, IVidzu ill 

tbe Comtbo7lJe: jlidgmentJ ~Made in tbe Sbade, 3 FED. CTS. L. REv. 177 (2009) (arguing that the 

overabundant, indefinite sealing of certain types of Judicial orders undelmines the legitimacy 

of those decisions). For the purpose of making gDod policy, unsealing, whether after a 

specified period or after specific conditions have been met, could facilitate greater 

transparency and provide C£)ngress with hetter infonnation ahout how the government uses 

ami courts apply surveillance authorities. Notwithstanding the potential utility of such a 

pohcv, however, we believe that the unsealing of court records raises serious security and 

privacy issues that require a complex and lengthy analysis that is beyond both the scope of 

ECP A reform and this Article. 

264. Title III of the Omnibm Crime Control and Safe Streets Act of 1968 for the first 

time authorized law enforcement personnel to monitor private telephone conversations. 

Pub. L. '(0. 90-351, tit. III, 92 Stat. 197,211-25 (codified as amended at 18 e.s.c. §§ 2511-

2520 (2010». The Act also provided strict guidelines and limitations on the use of wiretaps 

as a barrier to govemment infringement of individual privacv. One of the protections 

included by Congreso was the minimization requirement of 18 U.s.C § 2518(5). 

265. 50 U.s.C § 1861(gj (2009). 

266. Id. § 1804(a) (5). 
141 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 185 

obtained pursuant to Section 215 orders. Section 215 is a national security 

collection authority that allows the government to obtain both content and 

non-content information.267 

/\s such, we propose that Congress should require the DO], in 

consultation with State Attorneys General, to develop mles and procedures 

for tile minimization of location infonnation. Such mles would be intended 

to prevent the retention of infornlation that is not relevant to reasonable law 

enforcement purposes. Statutory language could be drafted as follows: 

The Attorney General, in consultation wicil State Attorneys General, shall 

adopt specific minimization procedures governing the retention and 

dissemination by governmental entities of location information received in 

response to an order under cilis section. 

In dlis section, dle term "minimization procedures" means specific 

procedures, reasonably designed in light of llie fonn and purpose of an 

order for the production of location information, to minimize dle retention 

and prohibit dle dissemination of non-publicly available location 

information concerning non-consenting persons, consistent willi dle need 

of law enforcement to obtain, retain, produce, and disseminate infornution 

dut: 1) is evidence of a crime; or 2) concerns the location of a person who 

is committing, has committed, is about to com1111t, or is a victim of a felony 

offense; or 3) is otherwise relevant and material to an ongoing criminal 

investigation and to be retained or disseminated for law enforcement 

pmposes. 

This language gives the Attorney General, in conjunction with the State 

Attorneys General, the flexihility and discretion to design minimization rules 

and procedures consistent with law enforcement needs while minimi7ing the 

retention and dissemination of location data that is not or is no longer 

relevant to legitimate law enforcement purposes. 

2. Notificatioll 

Covert surveillance methods are investigative tools that by their very 

nature invade the privacy of those targeted and are, as history has shown, 

prone to abuse. 26B To ensure these surveillance powers are restricted to 

267. Section 1861 of Title 50, commonly referred to as "Section 215 Business Records," 

permits the government to ohtain, with a rrSA court order, any "tangihle thing" for certain 

types of national secU1~ty investigations. Such Section 215 minimization procedures were 

intended to minimize tlle retention and prohibit tlle dissemination of non-publicly available 

infi:mnation conceming Cnited States persons consistent with national secU1~ty interests. See 

§ 1861(g). 

268. See Julian Sanchez, Wiretappinlr True Danger, L.A. TIMES (Mar. 16, 2(08), http:/ / 

articlcs.latimcs.com/2008/ marl 16/ opinion/ op-sanchcz16 C\Vifuout meaningful oversight, 

presidents and intelligence agencies can-and repeatedly have-abused fueir surveillance 
142 

186 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

legitimate law enforcement investigative needs, surveillance of l11nocent 

persons should be limited whenever possible and, whenever employed, it 

should not remain secret indefinitely. Such transparency facilitates social and 

congressional oversight of government use of surveillance techniques: 

individuals who may have been inappropriately or illegally monitored are 

provided with information and resulting incentives that may motivate them 

to pursue personal remedies, such as placing facts about the surveillance in 

the public record. Indeed, a disclosure mechanism that will raise public 

awareness of, and stimulate public discourse about, the scope and frequency 

of government surveillance activities may serve as an important deterrent to 

grahlitous use or abuse of these powers. 

In both the \\firetap Act and the Stored Communications Act, Congress 

created mandatory notice requirements that guarantee that subjects of some 

forms of law enforcement surveillance would be told that their 

communications have heen intercepted or accessed. 269 Such notice provisions 

act as an important privacy protection that particularly henefits those who are 

subjects of surveillance but never charged with a crime. \Vl1ile those who are 

evenrually arrested and charged might otherwise learn that they have been 

the target of surveillance (through the disclosure of search warrants, 

affidavits, and other documents), those who are not charged would never 

know about their surveillance histories were it not for the existence of notice 

requirements in existing surveillance laws. 

\Ve propose a similar notice requirement for those individuals whose 

location information is obtained by law enforcement agencies. This 

requirement will apply to those individuals targeted in location orders, as well 

authority to 'py on political enemies and dissenters. .. [AJ thorough congressional 

investigation headed by Sen. FnUlk Church (D-Idaho) revealed that for decades, intelligence 

analysts-and the presidents they served-had spied on the letters and phone conversations 

of union chiefs, civ;l rights leaders, joumalists, antiwar activists, lobbyists, members of 

Congress, Supreme Court Justices---cven Eleanor Roosevelt and the Rev. Martin Luther 

King Jr. The Church Committee reports painstakingly documented how the information 

obtained was often 'collected and disseminated in order to serve the purely political interests 

of an intelligence agency or the administration, and to influence social policy and political 

action.' "). 

269. See 18 USc. § 2518(8)(d) (Wiretap Act notifications) and §§ 2703(b)(1)(B), 2705 

(TICP A notifications). ECPA notifications only apply to the di,closure of content (not noncontent) and then only when a § 2703(d) order or subpoena is used to compel content. If 

using a Rule 41 warrant to compel content, at least one court held that the government only 

has to notify the service provider, not the customer or subscriber. Ttl re Application fi:>r 

Warrant for E-mail _Account lredactedJ@gruaiLcom Maintained on Computer SenTers 

Operated by Google, Inc., Headquartered at 1600 Amphitheater Parkway, Mountain View, 

CA, Mag. No. 1O-291-M-01 (DD.C. Nov. 1,2010) (Lamberth,].), amilable athttp://www.dcd. 

uscourts.gov-j dedi sites I dedi files I maglO-291.pdf. 
143 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 187 

as innocent individuals whose infonnation may be obtained as part of 

disclosures associated with specific places or community of interest requests. 

In addition to facilitating transparency and providing notice to impacted 

individuals, this requirement will, similar to existing compensation 

requirements,270 discourage law enforcement agencies from making 

unnecessary requests for large amounts of data,271 as the cost of notifying 200 

people will presumably be greater than that of notifying only twenty. This 

requirement could be drafted as follows: 

(a) NOTIFICATION.-

(1) Within 90 days after the disclosure of historical location information, 

or the expiration of an order authori7,ing prospective location information, 

the governmental entity shall serve upon, or deliver by appropriate 

means,272 the customer, subscriber, or user whose location was disclosed 

with notice that-

(A) states with reasonable specificity the nature of the law enforcement 

inquiry; and 

(B) informs such customer, subscriber, or user that their location 

information was supplied to that govemmental authority, and the date 

on which such disclosure was made. 

(2) Extensions of the delay of notification of up to 90 days each shall be 

granted by the court upon application hy a governmental entity if the 

court determines that there is reason to helieve that notification of the 

existence of the court order may have an adverse result described in 

paragraph (3) of this subsection. 

(3) An adverse result for the purposes of paragraph (2) of this subsection 

lS270. See HOIIJe Judiciary 2010 Ec..l'A Rt/orm Hearil{f!" mpra note 18, at 32 (written 

statement of Albert Gic1ari, Perkins Coie LLP) ("\~11en recorc1s are 'free,' such as with phone 

records, law enforcement over-consumes with abandon. . .. But when service providers 

charge for extracting data, such as log file searches, law enforcement requests are more 

tailored. ") 

271. William J Stuntz, The Distriblltion 0/ Fotlrtb Atnel2dtnellt Privacy, 67 CEO. WASH. L. 

REV. 1265,1275 (1999) ("[I]fyou tax a given kinc1 of [law enforcement] behavior, you ,,~ll 

probably see less of it."). 

272. Due to the widespread popularity of prepaid phones, many communications 

carriers do not have a name or address on file for large nlUnbers of their customers. As a 

result, it would not be possible for the carriers to notify these customers via U.S. mail 

(something requirec1 for surveillance of internet communications content perfOTlTlecl uncler 

18 U.s.c. § 2705(a) (5». The use of the term "appropriate means" is designed to enable 

companies to notlfy their customers v-ia a conmmnicatlon medium that is appropriate to the 

service they offer, and the contact information they have on file. This could include, for 

example, email, or mobile text message ("SMS"). 
144 

188 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

(A) endangering the life or physical safety of an individual; 

(H) flight from prosecution; 

(C) destruction of or tampering with evidence; 

(D) intimidation of potential witnesses; or 

(E) otherwise seriously jeopardi7,ing an investigation or unduly delaying 

a trial. 

(b) PRECLUSION OF NOTICE TO SUBJECT OF GOVERNMENTAL 

ACCESS.-A governmental entity acting under section [xl may apply to a 

court for an order commanding a provider of an electronic location service 

to whom a court order issued under section ~'\;'l is directed, for such period 

as the court deems appropriate, not to notity any other person of the 

existence of the court order. The court shall enter such an order if it 

determines that there is reason to believe that notification of the existence 

of the court order will result in-

(1) endangering the life or physical safety of an individual; 

(2) flight f,'om prosecution; 

(3) destruction of or tampering with evidence; 

(4) intimidation of potential witnesses; or 

(5) othenvise seriously jeopardizing an investigation or unduly delaying a 

trial. 

This section requires the law enforcement agency to notify all persons whose 

location information it obtains within ninety days after either the disclosure 

of historical data or the end of prospective surveillance. Individuals shall be 

notified via "appropriate" means, which could be a series of text messages, 

an email, or a letter, depending on the contact information known to law 

enforcement. As with other notitlcation statutes, the proposed section also 

permits the government to seek further delay of notice with cause, as well as 

prohibit a location provider from telling a target that her location 

information has been disclosed. \\7hen notifying innocent third parties that 

their location information was disclosed (incidentally) as part of a "broad" 

authorization, the governmental entity making the notitlcation should 

consider language that communicates the benign nature of the disclosure. 

3. SurtJeill!llICe S tatisties 

W'hen Congress created both the wiretap and pen reb rister/trap and trace 

interception statutes, it mandated the annual publication of aggregate 
145 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 189 

statistical reports 273 that were "intended to form the basis for a public 

evaluation of [the statute's] operation [and] will assure the community that 

the system of court-ordered electronic surveillance . . . is properly 

administered.,,274 Since at least 1998, the Administrative Office of the United 

States Courts ("/\0") has made copies of these reports available to the 

general public via its website.275 The public release of the annual report 

usually leads to media coverage highlighting the increased use of wiretaps.27G 

These statistics also provide a rich source of information for scholars 

wishing to study and report on the ever-increasing use of electronic 

sllrveillance. 277 By comparing these reports, scholars have been able to 

observe several notable surveillance trends. These include that the majority 

of wiretaps are for dmg crimes;278 that courts rarely, if ever, refuse wiretap 

applications;279 that the vast majority of wiretaps target mobile phones/So and 

the ever-growing use of wiretaps by state law enforcement agencies. lSI 

273. SeeJtlpll1note 171. 

274. S. Illip. '(0. 9()-1097, at 69 (196il), reprinted itl 196il U.S.CCA.K. 2112, 21S:=i, atld 

at!ailable at 1968 'lVL 4956. at *2185. 

275. See, e,r,., ADMI'f. OrneE or TIlE U.S. COCRTS, 1997 WIRETAP RI:;PORT (1998), 

h ttF/ /web.archive.org/weh/ 19981206135425/www.uscourts.gov/wiretap/contents.ht1111. 

276. See, e,fl,., National Xews Bliels; Record Tota! ol Wirett(Pj" Was /Jpproved by L0I111J~ N.Y. 

TIMES (May 10, 199il), http://nyti.lm/IhNhQj; Sman Stellin, (;o11lpressed Data; Who~r 

TJ/TatdJing? No. Who's listetling III?, NY TIMES aune 3, 20(2), http://nyti.ms/Ih,(p2d; Ryan 

Singel, Police ltYirott(Ppil(r, .ltlmps 26 Percellt, WIRED (Apr. 30, 2(10), http://www.wired.com/ 

threatlevel/201 0/04/ wiretapping/. 

277. See Ootid Based Lomplltil{1!, Heanl{l!" JIIPIl1 note 165, at 130 (oral answer from Fred 

C:ate, Prof. and Director, Or. for Applied C:yhersecurity Research, Ind. Cniv., to C:hainnan 

Nadler) ("[Surveillance] statistics gives Congress a sound empirical basis on which to 

evaluate how its laws are being used and whether they need to he changed. It also provides 

that same information for people such as those of LIS gathered at this table when making 

recommendations to Congress. And it provides infolmation to the public and the press so 

that they know how those laws are heing used and to what effect."); Jee aLro Soghoian, slijJm 

note 170. 

27R Soghoian, .Clpra note 17(), at 9 ("[Ivqore than 86 percent of the 2306 wiretap orders 

obtained [in 2009] by federal and state law enforcement agencies were sought in narcotics 

investigations."). 

279. See id. at 6-7 ("De tween 1987 and 2009, law enforcement agencies requested over 

30,000 wiretap orders .... DU1~ng the more than 20 years for which public data exists, 

requests for wiretap orders haye heen rejected just 7 times, twice in 1998, once in 1996, 

twice in 1998, once in 2002 and once in 2005."). 

280. See id. at 7 ("96 percent (2,276 wiretaps) of all authorized wiretap for 2009 are for 

portable devices."). 

281. See id. at 12 ("Over the last decade, the use of electronic surveillance orders has 

increased nationwide, although this is largely due to a massive increase in use hy the 

states .... [California and New York] arc now responsible for a combined 58 percent of all 

state wiretap orders."). 
146 

190 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

\~'hile much is known about the scale and use of wiretaps and, to a lesser 

extent, Pen/Trap surveillance, law enforcement requests for location 

information arc largely a "known unknown.,,282 '\lireless companies and their 

represent:ltives h:lve provided, :It hest, :l p:lrti:ll picture whose det:lils emerge 

only through Freedom of Information I\ct requests :lnd other investigative 

reporting techniques by privacy advocates. 283 That picture is not sufficiently 

clear to guide Congress regarding the use of this surveillance technique.2~4 To 

remedy this deficiency, we propose a specific reporting requirement that will 

enable Congress to know as much about the state of location surveillance as 

it currently knows :lhout wiret:lps :lnd would, :lS Sen:ltor P:ltrick Le:1hy h:ls 

described, provide a "f:lr more reliable basis th:ln anecdot:ll evidence on 

which to assess law enforcement needs and make sensible policy in this 

area.,,285 This standard could be drafted as follows: 

(a) GENERAL RCLEIVL~KING AUTHORITY FOR REPORTS UNDER 

THIS SECTION.-The Director of the Administrative Office of the 

United States Courts may make 1Ules regarding d1e content and form of d1e 

reports required under d1is section. 

(h) REPORTS CONCERl'ING DISCLOSURES.-

(1) TO ADil/lIKISTRATI'v'E OFFICE.-Not later than 30 days after the 

issuance or denial of an order WIder this chapter compelling the 

disclosure of location information, the issuing or denying judge shall 

report to the Administrative Office of the United States Courts-

(A) the fact that an order was applied for; 

(B) the type of order applied for; 

(C) whether the order was gr<mted as applied for, was modified, or was 

denied; 

(D) whether the court also granted delayed notice and the num.ber of 

tirnes such delay was granted; 

(E) the offense specified in the order or application, or extension of an 

order; 

282. News Transcr~pt, U.S. Dep't of Defense, DoD News Briefing-Secretary 

Rumsfeld and Gen. Myers (reh. 12,20(2), available athttp://www.defeme.gov/tramcripts/ 

transcript.aspx?transcriptid=2636 (,,[T]here are known knowns; there are things we know we 

know. We also know there are known unknowns; that is to say we know there are some 

things we do not know."); Jee (Jim Jupra Part T (discussing details about what is known 

regarding the scale of location surveillance). 

2S3. See generallY Soghoian, .rupra note 170. 

284. Id 

285. 145 COI'-G. Rb:c. 31,311 (1999) (statement of Sen. Leally). 
147 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 

(F) the identity, including district where applicable, of the applying 

investigative or law enforcement agency making the application and the 

person authorizing the application; and 

(G) the type of information or records sought in the order. 

(2) TO CONGRESS.-In April of each year the Director of the 

ll.dministrative Office of the United States Courts shall report to 

Congress with respect to the preceding calendar year-

(A) the overall total number of each of the events described in the 

subparagraphs of paragraph (1), regarding applications reported to that 

Office; and 

(R) a summary and analysis of the data described in paragraph (1). 

(c) PROVIDER REPORTING REQCIREMEKTS.-

(1) TO ADMINISTR/\TI,lE OFFICE.-Except as provided in 

paragraph (2), in January uf each year each provider of an electronic 

location service shall repurt with respect to the preceding calendar year to 

the Administrative Office of the United States Courts-

(i\) the number of legal demands and emergency requests received 

from Federal law enforcement agencies during the preceding calendar 

year for location information; 

(B) the number of legal demands and emergency requests received 

from State, local, and tribal law enforcement agencies during the 

preceding calendar for location information; and 

(C) the 111.U11ber of aCC01.U1ts about which location information was 

disclosed, specifying d1e numbers disclosed pursuant to legal demand 

and fue 111.U11bers disclosed voluntarily, to Federal, State, local, or tribal 

law enforcement agencies. 

(2) EXCEPTIONS.-The requirement of paragraph (1) does not apply 

to a provider of an electronic location service that, during the reporting 

period-

(A) received fewer than 50 requests combined from law enforcement 

agcncics; or 

(13) disclosed account information concerning fewer dun 100 

subscribers, customers, or od1er users; or 

(C) had fewer than 100,000 total customers or suhscrihers at the end 

of the calendar year. 286 

191 

286. The purpose of these statistics is to provide Congress, scholars, and the general 

public with information necessary to determine the scale of surveillance and to observ~e 
148 

192 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

(3) COMPE\rSATION.-The Director of the Administrative Office of 

the United States Courts shall provide reasonable compensation to a 

provider for the costs of compiling a report required wIder this 

subsection. 2R7 

(4) CONFTDFNTTALTTY OF TDFNTTTY OF SFR'v'TCF 

PRO'viDFRS.-The Director of the Administrative Office of the United 

States Courts shall establish procedures to prevent the release to the 

public of the identity of service providers with respect to disclosures they 

make under this subsection288 

(5) TO CONCRESS.-In April of each year, the Director of the 

Administrative Office of the United States Courts shall report to 

Congress with respect to the preceding calendar year-

(A) the total nwnbers of legal demarlds ,md of disclosures required to 

be reported under paragraph (1); ,md 

(R) a summary and analysis of the information required to be reported 

by paragraph (1), but without disclosing the identity of any service 

general trends. Information from small providers who receive just a handful of requests per 

year will not significantly aid in the ability to observe such trends, in comparison to tile tens 

of tilousands of requests received by large providers. FUlihelIDore, tilis notice requirement, 

while modest, could still be quite burdensome for a small provider. It is for this reason that 

we have opted to exempt such providers from tile statistical reporting requirements. 

2S7. As a general rule, companies are not in favor of regulations that are costly to 

comply witil. j\ltllough we do not believe tilat tile cost of compiling and submitting tilese 

reports will be exceedingly expensive (particularly given tllat Google already provides some 

data voluntarily), we have included a cCIDlpensatioll provision to avoid giving cornpanies a 

reason to lobby against it. We believe that tile data tilat will be made public as a result of tilis 

provision is worth the modest cost to the taxpayer. 

288. j\ltilough most large internet and telecommunications companies tilat handle user 

data receive both compulsory and voluntary location data requests from the government, 

few Wee to discuss tile topic publicly. As such, many companies might vigorously oppose tllis 

statistical reporting requirement if it would mean tilat tlleir names would be associated witil 

the data that eventually becomes published. In order to respond to companies' concerns, this 

provision has been drafted to ensure tint identities of tile companies will remain 

confidential: only aggregate statistics will be puhlished. In March 2010, Microsoft Associate 

General Counsel Mike Hintze told a reporter at TFiml tilat the reason Ivlicrosoft does not 

publish statistical data regarding tile number of legal requests tile company receives for 

customer infonnation is due to the fear of negative publicity. ''\Ve would like to see more 

transparency across tile industry," Hilltze said. "But no one company wants to stick its head 

up to talk ahout numhers." Ryan Singel, C()()gle, l'vficm.m/t Push Fedr To Fix Pril)ary L:iws, WIRED 

(!vIar. 30, 2010), http://www.wired.com/tilreatleveI/2010/03/google-microsoft-ecpa/; J"ee also 

Letter from 11ichael T. Gershberg, Counsel to YailOO! Inc, to William Bordley, FOIPA 

Officer, U.S. Marshals Servo 9 (Sept. 15, 2009), available at http:/ / cryptome.org/ yahoo-pricelist-letter.pdf ("lSurveillance pricingJ info=ation, if disclosed, would be used to 'shame' 

YailOO! and other companies-and to 'shock' their customers. Therefore, release OfYallOO!'S 

info=ation is reasonably likely to lead to impailIDent of its reputation for protection of user 

privacy and security, which is a competitive rusadv-antage for technology companies."). 
149 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 

provider with respect to dIe disclosures to law enforcement dlat service 

provider made. 

193 

This section creates a new statistical surveillance report for Congress that 

documents the issuance of orders compelling the disclosure of location 

infonnation. The A0289 will compile the annual report based on infonnation 

submitted to it by judges who have issued orders in response to government 

applications to compel location infonnation. The AO will then submit the 

compiled infonnation in a report to Congress. This section also requires 

providers of an electronic location service (other than those falling below a de 

minimis threshold) to submit annual reports regarding the number of 

compelled and voluntary disclosures of location infonnation they have made 

to the AO.290 The AO will then compile the data collected, produce a 

statistical summary containing no reference to the names of individual 

providers, and suhmit the information in a report to Congress. 

VII. CONCLUSION 

The use of location infonnation by law enforcement agencies is common 

and is becoming more so as technology improves and produces more 

accurate and precise location data. The legal mystery surrounding the proper 

law enforcement access standard for prospective location data remains 

unsolved and has created, along with conflicting rulings over the appropriate 

law enforcement access standard for both prospective and historical location 

data, a messy, inconsistent legal landscape where even judges in the same 

district may require law enforcement to meet different standards before 

authorizing law enforcement to compcllocation data. As courts struggle with 

these intertwined technology, privacy, and legal issues, some judges are 

expressing concern over the scope of the hanns, from specific and personal 

to general and social, presented by unfettered government collection and use 

of location data. 

289. The AO is the preferred entity to manage and execute this task because it is an 

objective, neutral organization and because it has historically produced the annual Wiretap 

Report (part of the Omnibus Crime Control and Safe Streets Act of ·1968) in an accurate, 

timely manner. See 145 CONGo REc. 31,311 (1999) (statement of Sen. Leally) (''The ~i\O has 

done an excellent joh of preparing the wiretap reports."). Placing the reporting hurden with 

the AO also prevents law enforcement from complaining that the reporting relluirements are 

turning "crinlefighters into bookkeepers." House Judiciary 2000 ECPA Hearil~g, Sltpra note 175, 

at 39 (statement of Kevin DiGregory, Deputy Assoc. Attorney Gen., Dep't of Justice). 

290. The AO is only capable of compiling information on court orders for location 

infonnation. Statistical data for voluntary disclosures made in emergencies can only come 

from the providers or law enforcement, and so we have opted to place this burden on the 

providers, who are then compensated for their trouble. 
150 

194 BERKELEY TECHNOLOGY LAW JOURNAL [Vol. 27:117 

This Article proposes model law enforcement access standards and 

downstream privacy protections for location information. This proposal 

attempts to (1) articulate clear rules for courts to apply and law enforcement 

agents and industry to follow; and (2) strike a reasonahle halance among the 

interests of law enforcement, privacy, and industry. We believe that our 

location information frame\vork could form a solid basis for legislation 

because, among other things, when measured against the current state of the 

law, it improves the position of all stakeholders appreciably. Industry gains 

clear rules to follow and is not overly burdened or exposed by reporting 

requirements. Law enforcement gains clear rules to follow that will not 

unduly limit their investigative activities, especially in light of certain existing 

policies voluntarily adopted by the DO]. Indeed, law enforcement's ability to 

acquire prospective location information to find individuals who have 

committed, are committing, or are about to commit a crime, when the 

location information itself is not evidence of a crime, is arguably improved by 

these proposed access standards. Moreover, law enforcement participation in 

a system that features tighter standards for initial access, as well as increased 

downstream privacy protections like minimi7ation and notice, will promote 

increased public trust in the integrity of the system and a corresponding 

increase in law enforcement's own credibility. 

Whle many privacy advocates have lobbied for a probable cause 

standard for all law enforcement access to location data, we have illustrated 

that this is not a realistic legislative goal in the current political climate or any 

immediately foreseeable one. Law enforcement will successfully argue that 

such a standard will unduly limit its investigative activities, including the 

ability to exclude someone from an investigation and spare her any 

unnecessary further inquiry into her personal life. Our proposal, however, 

offers privacy advocates clear rules that improve upon the current D Order 

standard and ensures that a probable cause standard will govern all law 

enforcement compelled disclosures of prospective cell phone location data. 

~foreover, this privacy framework offers privacy advocates a policy more 

protective than any threshold access standard alone can provide: downstream 

privacy protections that, among other things, ensure blTeater transparency and 

congressional oversight and minimize government authorities' retention of 

location data. /\s a legislative strategy, then, we submit that privacy advocates 

will stand on much firmer ground in supporting access standards aimed at a 

reasonable, legitimate balancing of stakeholder equities that also include 

downstream privacy protections. \\7hile privacy advocates can continue to 

fight for higher access standards for all location data in the courts, their 

constituents will not benefit from valuable downstream protections unless 

Congress includes them as part of reasonahle, palatahle ECP 1\ legislative 
151 

f 

2012] LAW ENFORCEMENT ACCESS TO LOCATION DATA 195 

reform. Our solution follows the suggestions of some jurists who have 

considered the potential social harms posed by location-based technologies 

and services: that Congress may be best suited to address these issues. We 

agree and offer the foregoing proposal as a strong initial step in that 

direction. 291 

291. During the writing of this Article, three bills in the 112th Congress were introduced 

proposing new law enforcement access standards for location data. See S. 1011, 112tb Cong. 

(2011); S. 1212, 112th Congo (2011); and II.R. 216S, 112th Congo (2011). None of these hills 

currently contain downstream privacy protections. Two of tbe bills, S. 1212 and H.R 2168, 

require a Ru1e 41 "probable cause" standard for all law enforcement compelled disclosures 

of location data, including the use of GPS tracking devices placed on cars. \v11ile S. 1011 

allows law enforcement to compel historical location data witb a D Order, tllere is no scope 

element addressing whether there is a mfficient ne""s hetween the alleged or suspected 

criminal activity and the scope of tbe location data relj1.1ested. See JNpra Sections IILC.l, 

III.C.2. S. 1011, like tlle two other bills, requires a Ru1e 41 "probable cause" showing for law 

enh:>rcement to compel prospective data (including the use of GPS tracking devices) but 

similarly does not take into account the "probable cause of what" problem tbat may inhibit 

law enforcement from acquiring the current or prospective location of a suhject who, for 

example, has committed a past crime when tbe subject's current or prospective location is 

not itself evidence of a crime. 
152 

*The Subcommittee had not received a response from this witness at the time this hearing 

record was submitted for printing, September 24, 2013. 

Questions for the Record submitted to Mark Eckenwiler, 

Senior Counsel, Perkins Coie LLP* 
153 

Enclosure 

Congressman John Conyers, Jr. 

Questions for Hearing Record 

"The Electronic Communications Privacy Act (ECPA), Part 2: 

Geolocation Privacy and Surveillance" 

The Subcommittee has received conflicting information regarding the extent to which the 

use of "microcells," "picocells" and "femtocells" impacts the accuracy of single tower 

location data obtained by law enforcement agencies. 

In his written testimony, Mr, Eckenwiler stated that "user-owned microcells .,. do not 

expand the network of towers available to the general population," adding that they "are 

only usable by their owners" and not by "other cell phone users" using the same wireless 

carrier,1 

Professor Blaze, however, observed in his written testimony that the general trend is for 

"cellular sectors [to] become smaller and smallerL] and [that] microcells, picocells, and 

femtocells are being deployed to provide denser coverage."2 

The recently published memo from the Center for Democracy and Technology on "Trends 

in Cell Site Precision" describes in greater depth the industry trend towards the 

deployment of femtocells. It notes, for example, that Sprint has distributed free femtocells 

to customers with poor 3G coverage, and has now deployed more than 1 million femtocells 

nationwide.3 

User manuals for the femtocells provided to consumers by AT&T, Verizon and Sprint are 

also very instructive on this issue,4 According to this carrier-supplied documentation, 

AT&T femtocells only provide service for phones on an "approved user list,"S while Verizon 

and Sprint femtocells appear to provide service by default to any active subscriber.6 

1 See hl:tll;jJlu.gig0I'yJl!lm.iig£!tihtClillllll.iiill~1!J.lil1U:UQJ.:YEck~!lwikromz j).Qj,:&'i~QJ3,ud[ at page 4. , Sec http; /ljudiciarl/,hpl!sGgmcllwariJli:,VLHlil/j)..:'l.Z.5.2.![LJ..il~~at page 15. 

3h!1pS: //www.cd~.org/mes/file icell·location·l'rccisioQ,pdf at page 2, 

4 T·Mobile does not currently use femtocell technology, 

5 hxtn:/1.ww..,.",atx,!'<1Jl.l fm cd ja lel1 U S ,{:m:l'j~J.:n2l:dVQ~0.~J!iil\1:n G M iCl'oCe II thrrMAillI!1Llllit at page 3 

("All 3G and 4G cell phones that receive wireless service from AT&T will work with the MicroCell if they are 

added online to the MicroCell's approved user Iist.") , 

6 b.1:t!);JJ:SJ)Jlj)Qn..\,i!.(iZQJ1!o'!.ir~lr.ss,comL.[l\lfl"'~twQrl< ~[WdJ;;LJru;r..llli\[L,gtJ2df at page 5 ["If you do not 

choose to manage the access to your Net\Vork Extender, other Verizon Wireless subscribers within range of 
154 

f 

For each of the witnesses, please provide any additional information to clarifY: 

1. The extent to which femtocells generally expand the coverage of wireless networks; 

2. Whether they provide service only to the phone of a customer which has installed 

the device, or to phones of other wireless subscribers who are nearby; and 

3. Whether wireless carriers are able to "filter out" high-accuracy femtocell data from 

historical or "real time" single cell tower data provided to law enforcement agencies 

in response to an order issued under 18 V.S.c. § 2703(d) or a "hybrid order?" 

your Network Extender will be able to use your Network Extender .. ,,"); See also 

i!ltj);U.J!P):l!l:rt.~pri llt(mn/ gIQh .. ll.ru!fL!Jli..<:U:\lJQ~"'l>"m~JlligLiljn)Y~LQlYl,.l'-lUilll.iuL,u.:l:ldf ["When the 

base station is set to aoen access, the first three callers detected within the base station's area are given 

access to place or rece-ive calls through the base station. Your base station is set to open access by default.") 
155 

Response to Questions for the Record from Peter A. Modaferri, 

International Association of Chiefs of Police 
156 

My understanding is that enhanced accuracy, which is the issue at hand, is a by-product of this 

business model - the service providers figured thi s business model was more cost effective than 

paying for a more towers and data connections in areas with only a few customers. 

2. Whether they provide service only to the phone of a customer, which has installed the 

device, or to the phones of other wireless subscribers who are nearby? 

Response: I am not certain whether femtocells are capable of only providing service to specific 

phones of individual customers. What confuses the issue is the conflicting information regarding the 

extent to which the use of "micro cells" "picocells" and "femtocells" impacts the accuracy of single 

tower location data obtained by law enforcement agencies can be found in the industries use of 

terminology. As I understand it, what is causing the confusion is the fact that the term "microcell" has 

been used in two ways in the cellular marketplace. Technically, a "microcell" is the next step down 

irom a "macrocell" (usually antennas mounted on a big tower) Historically, a "microcell" was a lowerpowered device that was attached to a water tower, tall building, church steeple, or whatever to fill in 

coverage gaps. So, it would cover a somewhat smaller area than a macrocell, but not dramatically 

smaller. 

The devices that providers are selling/giving to customers in poor coverage areas actually only cover 

the area immediately around a residence, considerably smaller than a true microcell. From a 

technical/engineering standpoint, it is my understanding that these are technically "femtocells" 

However, for marketing purposes companies determined that "femtocell" was too complicated for the 

average consumer to understand, hence, companies started advertising them as "microcells." This has 

significantly confused an already "muddy" situation. 

To complicate matters iurther, in the middle ground for this cell structure you have picocells, which 

are smaller than true microcells, but bigger than femtocells. Picocells are utilized for large government 

and private sector complexes. An example of this is can be seen in metropolitan subway stations. 

For clariiication, these are base stations (cell sites) in decreasing order of power, as I understand them' 

Macrocell (big tower) 

Microcell (lower-powered antenna to fill in coverage gaps in urban areas, attached to whatever is 

handy) 

Picocell (lower-powered unit to cover a specific building or area) 

Femtocell (little router-looking device that attaches to your home internet connection to make sure 

your cell phone works in your house ... sometimes called a "microcell" for marketing purposes) 

3. Whether the carriers are able to "filter out" high accuracy femtocell data from historical 

or real time single cell tower data provided to law enforcement agencies in response to an order 

issued under 18 U.S.c. § 2073d or a "Hybrid Order"? 

Response: Assuming that cell service providers can cull out femtocell information irom the inventory 

of data that they furnish to law enforcement - and it is not documented that they are able or willing to 

do so - the data that remains should pass constitutional muster. In fact. the 5,h Circuit Court of 

Appeals in Texas recently found that such information is unprotected under the Fourth Amendment, 

precisely because it is not the solely the phone user's information, but, rather, a business record the 

service provider keeps as part of the whole record of the delivery of the communication: 
157 

f 

In the case of such historical cell site information, the 

Government merely comes in after the fact and asks a provider 

to tum over records the provider has already created. 

Moreover, these are the providers' own rccords of tmnsactions to 

which it is a patty. The caller is not conveying location 

information to anyone other than his service provider. He is 

sending information so that the provider can perform the service 

for which he pays it: to connect his call. And the historical cell 

site information rcvcals his location information for addressing 

purposes, not the contenls of his calls. The provider uses this 

data to properly route his call, while the person he is calling does 

not receive this information.' 

It is plain that cell phone data docs not require a warrant merely becausc it is information about a cell 

phone. Instead, the analysis would begin and end with the intrusion level versus what, if any, privacy 

rights a subject surrenders when he allows a third party to access location ini(umation concerning his 

or her whereabouts'. 

Our core position is that the Icgal standard tbr accessing records should be based on how they at'e 

created (in the normal course of business vs. because of law enforcement demand, like a real-time 

remote geoloeate), not how precise they are. Again, a ealilo a residentiallandline gives a very precise 

location, but no one is suggesting that it needs a higher level of protection. 

I refer again to the quoted portion of the 5th Circuit opinion. The provider created the location record 

to properly route and deliver a phone call. That record may be a precise femtocell location or a less 

precise tower/sector location - it does not ma((er - the record was created by the provider for the same 

purpose. Precision or lack of precision should not be the determinant in the case of historical location 

infonnatioH. 

I know that many people do not belicve they have an expectation that the location information 

associated with their cell phone is private. How so? Because in a variety of investigations I have 

directed, thc subjects intentionally turned offthcir cell phones at some time prior to the crimes (even 

took the battery out of the devices) in order ensure that relevant location records were not created. 

Thank you again for this opportunity. As always, I stand ready to answer any questions that 

committee members may have for me. 

Very t

2

,,1 yours, 

/' ~-

/.~.--- /.;? ". vl'fiter A. Modaften 

Chief of Detecti vcs 

Rockland County District Attomey's Office 

, In Re: Application Of 'I' he United States Of America For Historical Cell Site Data, No. 11-20884 (5th 

Cir. July 30, 2013). 
158 

*The Subcommittee had not received a response from this witness at the time this hearing 

record was submitted for printing, September 24, 2013. 

Response to Questions for the Record from Catherine Crump, 

Staff Attorney, American Civil Liberties Union (ACLU)* 

"'.="'-

Ms. C~th=rine Crump 

SllIff Auorney 

ACLU 

[nngrrns of thE 'linitrd ~mtEs 

t lDU8t nfl{rprcsrnmtlors 

COMMnTU 0,. THE JlJ\l!CIfJlv 

]',. ..... __ Qo~ ... I1""_, 

W_'o><!l(:"",~" 

'~1Im..¥1 

---JUlle21,2013 

l2S B!OO.d Slr\...:I, 18th Floor 

NCWYOfk.N\' lOOlJ.l 

[.lear Ms. Crump. 

1'he Judicia!), Commillec'B Sul!commiu<'I: On Crim~. Troori.m.IlOO1Cland S«urity.nd 

In~ .. !j&llli""" held a hearing on "The Eleel"",ic Communica1i"", Pri~y Act{ECl'A.), Part 2; 

<lfl>IOCIIlion PrivlloCY and S",,'eUlal\CC,~ 011 Thursday, April 25, 2013 at 10:00 •. m in room 21~1 

of!he Raybltm Ilou"" Office Building. ThJn~ you fm your teSlimony. 

Que<tion. for !he rccnttl h,aV1: ~n submitted to !he Subcommittee within live ICHisl.live 

day~ "flho. hearing. The que,ui.oo.ll !ldd~ 10 yoo"rc al1achc<i. We will "ppttt;ale. fulllllld 

complele response as Lhey will be included in lh. official hewing m;oro. 

Pleue ,ubmil your wril1cn InSwers to Alici. Church at alida.cl!yrch!\jlmail.tIOYK.W.W or 

B·3]09 Rayburn 110= Omce Buildin!\. Wamlngton, DC, 20~IS by July 26. 2013. [f)'Oll have 

1liiy flJl'\h<or qll<'slio!lll or C<Jocems, please C<Jnl8ct or 31 201'nS-5n7. 

Thank you agllin for your part;c;p<:uioo ;n !he hearing. 
159 

Enclosure 

Congressman John Conyers, Jr. 

Questions for Hearing Record 

"The Electronic Communications Privacy Act (ECPA), Part 2: 

Geolocation Privacy and Surveillance" 

The Subcommittee has received conflicting information regarding the extent to which the 

use of "microcells," "pica cells" and "femtocells" impacts the accuracy of single tower 

location data obtained by law enforcement agencies. 

In his written testimony, Mr. Eckenwiler stated that "user-owned microcells ... do not 

expand the network of towers available to the general population," adding that they "arc 

only usable by their owners" and not by "other cell phone users" using the same wireless 

carrier.1 

Professor Blaze, however, observed in his written testimony that the general trend is for 

"cellular sectors [to] become smaller and smallerL] and [that] microcells, picocells, and 

femtocells are being deployed to provide denser coverage."2 

The recently published memo from the Center for Democracy and Technology on "Trends 

in Cell Site Precision" describes in greater depth the industry trend towards the 

deployment of femtocells. It notes, for example, that Sprint has distributed free femtocells 

to customers with poor 3G coverage, and has now deployed more than 1 million femtocells 

nationwide.3 

User manuals for the femtocells provided to consumers by AT&T, Verizon and Sprint are 

also very instructive on this issue.4 According to this carrier-supplied documentation, 

AT&T femtocells only provide service for phones on an "approved user Iist,"S while Verizon 

and Sprint femtocells appear to provide service by default to any active subscriber.6 

1 See httll;i/Jlllij(:j1JIYJ1£!Jl';;UNS/l1J,al'ing,(113th/MIS.ZilUJJlcl~ZlJQ'tZ~lin;111[![ at page 4. 

2 See http://judiciary.house.gov(hearings 1113t11/Q4252Q'I 3/Blaze%20Q4252013.pdf at page 15. 

3 Illt!)s: /lwww.cdt Qrg/files/fiJe(cell·location'precision.Ddf at page 2. 

1 T· Mobile does not currently use femtocell technology. 

5 hlli.!l,L,6:/ww.att CQm!IDs:lJiilL~1LUSi£w1/3Gm.i,rt>[~Il/,,~e!st8J::r.:;'GMiCmCqll lJ,~!:.i:MJl.rolli.Lmlf at page 3 

["AIl3G and 4G cell phones that receive wireless service from AT&T will work with the MicroCell if they are 

added online to the MicroCell's approved user list."). 

6 h.tt!lJ,llillpporl.vCm(lnwirJ:il:;i.&IlJl~j;~lil'smlCkLlI~"Ltrlilll!!:i!l4ll!f at page 5 ["[fyou do not 

choose to manage the access to your Network Extender, other Verizon Wireless subscribers within range of 
160 

f 

For each of the witnesses, please provide any additional information to clarify: 

1. The extent to which femtocells generally expand the coverage of wireless networks; 

2. Whether they provide service only to the phone of a customer which has installed 

the device, or to phones of other wireless subscribers who are nearby; and 

3. Whether wireless carriers are able to "filter out" high-accuracy femtocel! data from 

historical or "real time" single cell tower data provided to law enforcement agencies 

in response to an order issued under 18 USc. § 2703(d) or a "hybrid order?" 

your Network Extender will be able to use your Network Extender .... "): See also 

~1'0It.sl)riil1.LomLgllIllilVJ)(li/JJfi1:LIWi'les/"'mSll1]!;/jllCi:!.~~J.diDly-'",l:l)!,sllrinU,g,pd(("When the 

base station is set to open access, the first three callers detected within the base station's area are given 

access to place or receive calls through the base station, Your base station is set to open access by default") 
161 

Response to Questions for the Record from Matt Blaze, Professor, 

University of Pennsylvania 
162 

itsel( Otber than that, the various small celltechllolog;es 3re largely similar,) From the 

telephone users' persp~tive, calls served by small cells and those served by large cells 

are effectively indistinguishable, and a user today is likely to encounter both large and 

small cells throughout the day or even during a mobile call , 

Small cell base stations expand the coverage of wireless networks in two imponallt 

ways_ First. because they arc typically located on or near the panicul~r premises that 

they are intended to cover, they expand Tadio sigoal coverage of the network (the "bars" 

displayed on a phone handset) into areas where radio signals from large base stations 

may be blocked by opaque envirOlllllental features such as buildings, foliage, and 

terrain such as hills or valleys. Small cells afe especially imponant for extending 

coverage inlO indoor areas such as private homes 3nd businesses_ Large base stations 

are typically located outdoors, atop buildings or on towers, and to serve a wider 

geographic area, but at the expense of complete coverage within thaI area. 

Second, small cells expand the capacity of the network to serve more customers 

simultaneously. Each bltse statioll, Ivhether small or large, has only II. limited amount of 

bandwidth available to it, II. fraction of which ;s occupied whenever a customer makes a 

call or uses a data service, (Wireless carriers have limited chunks of radio spectrum 

bandwidth Ih8t they can use to provide cellular service: this difectly translates to II. fi .... ed 

number of phone calls, text messages. and data thaI II. carner can accommodate in a 

given geographic area.) Addi ng small cell base stations makes it possible to serve more 

customers by allowing the !lnite amount of radio spectrum allocated to wireless comers 

to be re-used within a smaller area, 

For these reasons - ensuring good coverage 10 indoor areas and more efficiently using 

scarce radio spectrum - the deploymel1l of small cell base stations such as femtocells is 

growing and can be expected to continue to grow at II. fast pace. They are onen the only 

effective way a carri er can e .... pand coverage to eliminate weak-sig.nal areas and increase 

usage capacily . FrOIll the user's perspective, the increased proliferation or small cell 

base stations means that the likelihood that any given call will be served by a small cell 

is growing rapidly This is espocially lrue in urban areas and other places with a high 

density of cellular users. 

Q uestion 2: Whether 'hey prol'id,' senice flllly 10 IIii.' pllO/I!.' of a CIiS/Ulller which has 

IIIsrall,'(I flit' del"lee, ur fV phv/lI!~' (if Olher wireless Sllbscrilu'fS whu "re lIearby. 

Re~ lon se: Carrier-maintained small cells {micfoceUs, picoceits, etc.} will generally 

serve the phone or any subscriber within range, For customer-maintained fenllocells, 

whether they will provide !;Crvice ror other subscribers depends on how they are 

contigured. Today, some earners provide femlOCclis configured to serve only 

specifically-designated subscribers by default. Other providers. including Vcrizon 

Wireless and Sprint Nelllel, currently prollide femtocells configured to serve any 

sub,scriber by default, 

U NIVERS IT'i' of PENNSYLVANIA 
163 

Æ 

Because small cells are an esse-utia) part of expanding future network coverage and 

capacity in dense areas. we can c."Pcct the trend to be toward open femtocells. either 

through default configuration or by carriers providing incentives for cuSlOmers to tum 

the feature on. Also, as noted above, there are other kinds of small cells that are 

installed and maintained directly by the carrier (rather than by customers), and these 

cells are still open to all subscribers even when customer-maintained femtocells of that 

carrier might not be. 

Q uest ion 3: W/I('II1('r wirefl.'s.I' c(ll'ril.'r,l· lire (Ihk IV ''ji/JI.'I' (JI,I" high-an:uff/cy /l.'lIIlOc"'l 

dalajrom hisloricu/ qr "rifallillll.''' sm!;le CI'I/ IUII'I'/' ull/a provitl('d fa laU' 1'1!{tJrC('/IIelll 

ll~ell cies;/I rt'sIXJII.W IV ( 1/1 orde/' isslled III1c1er 18 WiC § J.703(cI) (Ir (/ "hybrid order?" 

RtS IJO nSt: Whether a camer can filter out customer-maintained femtocell records from 

data provided to law enforcement will depend on the policy and technical capabilities 

of the panicular carrier. Among olher things, it will depend upon how such cells are 

identified in a given carrier's internal databases and whether they can be distinguished 

from other base stations at the time records are e"macted for law enforcemellt use. 

For other kinds of smal l-cells, particularly those maintained by the camer (as OPPO&ed 

to a cUStomer), it will be more difficult for carriers to filter their records. This is 

becaus~ there is little technical distinction, for the purposes of a wireless camer's 

operations, between a small cell and a large cell. Indeed, the difference between camermaintained small cells and large cells is more of a continuum of their coverage size 

than a bright-li ne distinction. 

Movillg forward. we can e)(pt:ct to see wireless networks wilh an iJ1creasing proportion 

of small cells (which will consist of a tombination of carrier-maintained small cells and 

customer-maintained small cells). particularly in dense areas Even if it were possible 

\0 do so, filtering OUt all small cells from call record data provided to law enforcement 

could, in many cases, leave location infonnation in few or none of call detail records 

for many targets. because a large fraction of calls will be served by such cells. 

Thank you again for the opponunity to respond to these que~ ions. Please feel free to 

contact me if I can be of any further assistance. I can be reached via email at 

bl aze@cis.upenn ,edu. 

Sincerely 

M

~~ att Blaze . 

UNIVEItS ln ' of PENNSYLVANIA