In the 

United States Court of Appeals 

For the Seventh Circuit ____________________

No. 15‐2443

UNITED STATES OF AMERICA,

Plaintiff‐Appellee,

v.

DAMIAN PATRICK,

Defendant‐Appellant.

____________________

Appeal from the United States District Court

for the Eastern District of Wisconsin.

No. 13‐CR‐234 — Rudolph T. Randa, Judge.

____________________

ARGUED MAY 24, 2016 — DECIDED NOVEMBER 23, 2016

____________________

Before WOOD, Chief Judge, and EASTERBROOK and KANNE,

Circuit Judges.

EASTERBROOK, Circuit Judge. Police in Wisconsin arrested

Damian Patrick while he was in a car on a public street and

found him armed. That led to this federal prosecution, be‐

cause Patrick’s criminal record made it unlawful for him to

possess firearms. 18 U.S.C. §922(g)(1). The district court de‐

nied his motion to keep the gun out of evidence. 2015 U.S.
2 No. 15‐2443

Dist. LEXIS 1421 (E.D. Wis. Jan. 7, 2015), approving a magis‐

trate judge’s recommendation, 2014 U.S. Dist. LEXIS 179522

(E.D. Wis. Sept. 30, 2014). Patrick pleaded guilty but reserved

the opportunity to contest the validity of his arrest, and thus

the validity of the gun’s seizure. He now appeals from the

57‐month sentence he received.

Patrick was serving a term of parole that followed his re‐

lease from state prison. He did not comply with the condi‐

tions of his release, and a warrant was issued for his arrest.

(He does not contest that warrant’s validity.) In an effort to

find Patrick, Milwaukee’s police obtained a second warrant,

which authorized them to locate Patrick using cell‐phone da‐

ta. Patrick’s cell phone revealed his location, which enabled

the police to find him.

Patrick attempts to undermine the validity of the loca‐

tion‐tracking warrant by contending that his person was not

contraband or the proceeds of a crime, and that it therefore

was off limits to investigation. That sounds like an attempt

to resurrect the “mere evidence” doctrine that the Supreme

Court disapproved in Warden v. Hayden, 387 U.S. 294 (1967).

Hayden authorized the use of warrants to get evidence to lo‐

cate a wanted person. See also Steagald v. United States, 451

U.S. 204 (1981) (search warrant to enter house to look for

person to arrest). Police were entitled to use a warrant to ob‐

tain data that would help them track down Patrick’s location.

Indeed, they were entitled to arrest him without a war‐

rant of any kind, let alone the two warrants they had. United

States v. Watson, 423 U.S. 411 (1976), holds that probable

cause alone is enough for an arrest in a public place. A war‐

rant is necessary only when the police need to enter a private

area to capture the wanted person. See Payton v. New York,
No. 15‐2443 3

445 U.S. 573 (1980). Because Patrick was visible to the gen‐

eral public, he did not have any privacy interest in his loca‐

tion at the time.

More: the Supreme Court recently held that a valid arrest

warrant precludes the suppression of evidence seized in an

arrest, even if the arrest was set in motion by officers who

had neither probable cause nor knowledge of the warrant.

Utah v. Strieff, 136 S. Ct. 2056 (2016). Strieff tells us that, if the

police had stopped Patrick’s car for no reason at all and

learned only later that he was a wanted man, the gun would

have been admissible in evidence. The officers who nabbed

Patrick, by contrast, had both probable cause to believe that

he was a fugitive from justice and knowledge of the arrest

warrant. The gun cannot be less admissible than in Strieff,

even if we knock out the means used to track his location.

Because Patrick was arrested in a public place, and the

arrest was supported by both probable cause and a valid ar‐

rest warrant that had been issued before any effort to learn

his location (an effort that therefore could not “taint” the ar‐

rest in the parlance of the exclusionary rule), we need not

resolve some difficult issues posed by a fact that came to

light while the case was in this court. After Patrick filed his

opening brief, the prosecutor revealed that Patrick’s location

had been pinned down using data from a cell‐site simulator.

That device (often called a Stingray, the trademark of one

brand) pretends to be a cell‐phone access point and, by emit‐

ting an especially strong signal, induces nearby cell phones

to connect and reveal their direction relative to the device.

Here is a description from the Department of Justice:

Cell‐site simulators ... function by transmitting as a cell tower. In

response to the signals emitted by the simulator, cellular devices
4 No. 15‐2443

in the proximity of the device identify the simulator as the most

attractive cell tower in the area and thus transmit signals to the

simulator that identify the device in the same way that they

would with a networked tower.

A cell‐site simulator receives and uses an industry standard

unique identifying number assigned by a device manufacturer

or cellular network provider. When used to locate a known cellu‐

lar device, a cell‐site simulator initially receives the unique iden‐

tifying number from multiple devices in the vicinity of the simu‐

lator. Once the cell‐site simulator identifies the specific cellular

device for which it is looking, it will obtain the signaling infor‐

mation relating only to that particular phone. When used to

identify an unknown device, the cell‐site simulator obtains sig‐

naling information from non‐target devices in the targetʹs vicini‐

ty for the limited purpose of distinguishing the target device.

By transmitting as a cell tower, cell‐site simulators acquire the

identifying information from cellular devices. This identifying

information is limited, however. Cell‐site simulators provide on‐

ly the relative signal strength and general direction of a subject

cellular telephone; they do not function as a GPS locator, as they

do not obtain or download any location information from the

device or its applications. Moreover, cell‐site simulators used by

the Department must be configured as pen registers, and may

not be used to collect the contents of any communication, in ac‐

cordance with 18 U.S.C. §3127(3). This includes any data con‐

tained on the phone itself: the simulator does not remotely cap‐

ture emails, texts, contact lists, images or any other data from the

phone. In addition, Department cell‐site simulators do not pro‐

vide subscriber account information (for example, an account

holderʹs name, address, or telephone number).

Department of Justice Policy Guidance: Use of Cell‐Site Sim‐

ulator Technology (Sept. 3, 2015) at 2. See also the Wikipedia

entry at <en.wikipedia.org/wiki/Stingray_phone_tracker>.

If the Department’s description is accurate (a question not

explored in this litigation) law‐enforcement officials get the
No. 15‐2443 5

same sort of information that a phone company could pro‐

vide using its own facilities, and they get it in real time ra‐

ther than waiting for the phone company to turn over data.

But instead of collecting information on just one person, as

the warrant in this proceeding entitled the police to learn

Patrick’s location, a cell‐site simulator collects the relative

location of everyone whose phone is induced to connect to the

simulator—though it may discard that information before

alerting officials to the presence of the sought‐after person

(just as the phone company, which has location data about

all of its customers, would disclose only one person’s loca‐

tion).

One potential question posed by use of a cell‐site simula‐

tor would be whether it is a “search” at all, or instead is cov‐

ered by Smith v. Maryland, 442 U.S. 735 (1979), and United

States v. Knotts, 460 U.S. 276 (1983). The former holds that a

pen register is not a search because it reveals the making of a

call, and the number called, but not the call’s communicative

content. The latter holds that the use of a beeper is not a

search, because it reveals a suspect’s location but nothing

else. Recent decisions such as United States v. Graham, 824

F.3d 421 (4th Cir. 2016) (en banc), and United States v. Carpen‐

ter, 819 F.3d 880 (6th Cir. 2016), apply these principles to

hold that tracking a person via data from phone companies

is not a search within the scope of the Fourth Amendment.

(Graham involved historical cell‐tower location information

and Carpenter involved “transactional records” from phone

companies, so both cases dealt with the sort of information

covered by the location warrant in this proceeding.) Police

freely use databases, containing information such as the ad‐

dresses associated with automobile license plates and per‐

sons licensed to drive, to track down suspects; they search
6 No. 15‐2443

trash for credit card receipts showing where he made pur‐

chases; they consult a suspect’s relatives and friends (and

sometimes his enemies) to learn his whereabouts; no one

thinks that those methods require a search warrant.

A contrary line of argument analogizes cell‐site simula‐

tors to GPS locators, which are treated as searches when po‐

lice enter private property to install them, see United States v.

Jones, 132 S. Ct. 945 (2012), and may be searches when used

for extended durations even if installed with a vehicle own‐

er’s consent, id. at 954–64 (concurring opinions of Sotomayor

and Alito, JJ.). If a cell‐site simulator is like a GPS tracker,

and if the approach of the concurring opinions in Jones is

adopted, then it would be necessary to know how long the

police used a simulator while searching for Patrick and just

how accurate is the location information it provides. (Is it

information that leaves uncertainty about where in several

city blocks a suspect may be, such as the beeper in Knotts, or

is it closer to the precise location supplied by a GPS tracker?)

Cf. Kyllo v. United States, 533 U.S. 27 (2001) (thermal image of

the inside of a house is a search, given a person’s strong pri‐

vacy interest in his dwelling).

The United States has conceded for the purpose of this

litigation that use of a cell‐site simulator is a search, so we

need not tackle these questions. The parties join issue, how‐

ever, on the significance of the fact that police did not reveal

to the state judge who issued the location‐tracking warrant

that they planned to use a cell‐site simulator—indeed, im‐

plied that they planned to track him down using his phone

company’s data. Patrick says that leaving the judge in the

dark (perhaps misleading the judge by omitting a potentially

material fact) makes the location‐tracking warrant invalid.
No. 15‐2443 7

This poses the question whether a judge is entitled to know

how a warrant will be executed.

The Fourth Amendment requires that warrants be based

“upon probable cause, supported by Oath or affirmation,

and particularly describing the place to be searched, and the

persons or things to be seized.” The Supreme Court stated in

Dalia v. United States, 441 U.S. 238, 256 (1979), that neither

constitutional text nor precedent suggests that “search war‐

rants also must include a specification of the precise manner

in which they are to be executed.” The manner of search is

subject only to “later judicial review as to its reasonable‐

ness.” Id. at 258. And the Justices added in Richards v. Wis‐

consin, 520 U.S. 385 (1997), that courts cannot limit a warrant

so as to foreclose a particular means of execution. In Richards

the police sought a warrant that would have authorized a

no‐knock entry to conduct a search. The judge denied that

request but issued a warrant for a regular search. After the

police conducted a no‐knock entry anyway, the Court held

that this was proper because it was reasonable to carry out

the search that way under the circumstances.

This means that the police could have sought a warrant

authorizing them to find Patrick’s cell phone and kept silent

about how they would do it. Or affidavits and the warrant

itself might have said that “electronic means that reveal loca‐

tions of cell phones” will be used. Professor Kerr has con‐

cluded from Dalia and Richards, and other considerations,

that the Fourth Amendment forbids judges to attempt to reg‐

ulate, ex ante, how a search must be conducted, and confines

the judiciary to ex post assessments of reasonableness. Orin S.

Kerr, Ex Ante Regulation of Computer Search and Seizure, 96 Va.

L. Rev. 1241, 1260–71 (2010).
8 No. 15‐2443

We can imagine an argument that it will often be unrea‐

sonable to use a cell‐site simulator when phone company da‐

ta could provide what’s needed, because simulators poten‐

tially reveal information about many persons other than the

suspects. (The contrary argument is that data from simula‐

tors is current, while data relayed through phone‐

companies’ bureaucracies may arrive after the suspect has

gone elsewhere.) But if the problem with simulators is that

they are too comprehensive, that would not lead to suppres‐

sion—though it might create a right to damages by other

persons whose interests were unreasonably invaded. Patrick

is not entitled to invoke the rights of anyone else; suppres‐

sion is proper only if the defendant’s own rights have been

violated. See, e.g., United States v. Payner, 447 U.S. 727 (1980).

Patrick contends that, even if ex ante authorization of the

method is unnecessary, the police must be candid with the

judiciary when they mention potential methods of executing

a search warrant. He seeks, at a minimum, a remand to ex‐

plore those questions, after the fashion of a Franks hearing

(see Franks v. Delaware, 438 U.S. 154 (1978)), at which the

court would decide whether the warrant still would have

issued if the affidavits had been more forthcoming.

But for the reasons given earlier we conclude that the an‐

swers do not control this appeal. A person wanted on proba‐

ble cause (and an arrest warrant) who is taken into custody

in a public place, where he had no legitimate expectation of

privacy, cannot complain about how the police learned his

location. Recall that the cell‐site simulator (unlike the GPS

device in Jones) was not used to generate the probable cause

for arrest; probable cause to arrest Patrick predated the effort

to locate him. From his perspective, it is all the same whether
No. 15‐2443 9

a paid informant, a jilted lover, police with binoculars, a bar‐

tender, a member of a rival gang, a spy trailing his car after it

left his driveway, the phone company’s cell towers, or a de‐

vice pretending to be a cell tower, provided location infor‐

mation. A fugitive cannot be picky about how he is run to

ground. So it would be inappropriate to use the exclusionary

rule, even if the police should have told the judge that they

planned to use a cell‐site simulator to execute the location

warrant.

The Department of Justice announced last September that

in the future it would ordinarily seek a warrant, plus an or‐

der under the pen‐register statute, 18 U.S.C. §3123, before

using a cell‐site simulator, but it has not conceded that this is

constitutionally required. Questions about whether use of a

simulator is a search, if so whether a warrant authorizing

this method is essential, and whether in a particular situa‐

tion a simulator is a reasonable means of executing a war‐

rant, have yet to be addressed by any United States court of

appeals. We think it best to withhold full analysis until these

issues control the outcome of a concrete case.

AFFIRMED
10 No. 15‐2443

WOOD, Chief Judge, dissenting. This case raises serious is‐

sues about the use of cell‐site simulators to track down the

location of a target person. That is how police found Damian

Patrick, for whom an arrest warrant had been issued for pa‐

role violations. My colleagues see no serious Fourth Amend‐

ment issues in Patrick’s case, because they believe that a de‐

fendant has no interest in the manner in which a warrant is

executed. They also question whether the use of a cell‐site

simulator is a “search” at all, noting that Smith v. Maryland,

442 U.S. 735 (1979), holds that the use of a pen register is not

a “search,” and that United States v. Knotts, 460 U.S. 276 (1983),

says the same thing about the use of a beeper. Finally, they

note that Patrick was arrested in a “public place,” by which

they mean sitting in the passenger seat of a parked car. All of

this matters greatly to Patrick, because if his initial arrest was

invalid, then the gun that the police spotted in plain view in

the car should have been suppressed as “fruit of the poison‐

ous tree,” see Wong Sun v. United States, 371 U.S. 471, 488

(1963), and Patrick’s conviction under 18 U.S.C. §§ 922(g)(1)

and 924(a)(2) for being a felon in possession of a firearm

would need to be revisited. If the arrest complied with the

Fourth Amendment, the gun was lawfully found and seized

and his conviction must be affirmed. Because I believe that the

panel opinion underestimates the relevant technology’s capa‐

bilities and extends Utah v. Strieff, 136 S. Ct. 2056 (2016), too

far, I dissent.

This is the first court of appeals case to discuss the use of

a cell‐site simulator, trade name “Stingray.” We know very

little about the device, thanks mostly to the government’s re‐

fusal to divulge any information about it. Until recently, the

government has gone so far as to dismiss cases and withdraw

evidence rather than reveal that the technology was used. See
No. 15‐2443 11

Memorandum Agreement between Amy S. Hess, Assistant

Director, Operational Technology Division, FBI, and David

Salazar, Chief of Police, MPD (Aug. 13, 2013) (agreeing to dis‐

miss cases rather than disclose use of Stingray). Indeed, in this

case, the government appears to have purposefully concealed

the Stingray’s use from the issuing magistrate, the district

court, defense counsel, and even this court. It ultimately ad‐

mitted its use of the device only in response to an amicus curiae

brief filed during this appeal.

Although, as we all agree, Patrick does not have standing

to challenge any location information gathered from other

persons’ cell phones, see Jones v. United States, 362 U.S. 257,

261 (1960), overruled on other grounds by United States v. Sal‐

vucci, 448 U.S. 83 (1980), he is entitled to challenge the use of

the Stingray itself, along with the gathering of any non‐loca‐

tion information from his cell phone.  

The record is painfully—indeed fatally—inadequate with

respect to critical details about the way the Stingray was used.

We are thus not in a position to determine whether (1) its use

was sufficiently outside the scope of the warrant to merit

blanket suppression; and whether (2) Patrick’s arrest (putting

the warrant to one side) was based in whole or in part on in‐

formation gathered in violation of Title III of the Omnibus

Crime Control and Safe Streets Act of 1968, 18 U.S.C. §§ 2510–

20 (if, as it may, that statute applies). Even if the Stingray re‐

vealed no information beyond Patrick’s location, we must

know how it works and how the government used it before

we can judge whetherit functions in a manner sufficiently dif‐

ferent from the location‐gathering methods specified in the

warrant that it amounted to a search outside the warrant’s

scope.  
12 No. 15‐2443

The majority offers a long quote from the Department of

Justice Policy Guidance manual on the use of cell‐site simula‐

tor technology, ante at 3–4, but that information is contestable.

We are given no reason to think that a municipal police de‐

partment such as MPD was bound in any way to the guidance

offered by the DOJ, or that the MPD chose to follow the DOJ

Guidance as a matter of internal policy. There is another side

to the story, but because of the government’s furtiveness, Pat‐

rick never had the chance to present it.  

With certain software (known as “Fishhawk” and “Por‐

poise”), the Stingray is much more than a high‐tech pen reg‐

ister. It can capture the “emails, texts, contact lists, images,”

and other data disclaimed by the last paragraph of the major‐

ity’s excerpt of the Policy Guidance. It can eavesdrop on tele‐

phone conversations and intercept text messages. See Stepha‐

nie K. Pell & Christopher Soghoian, Your Secret Stingray’s No

Secret Anymore: The Vanishing Government Monopoly over Cell

Phone Surveillance and Its Impact on National Security and Con‐

sumer Privacy, 28 HARV. J.L. & TECH. 1, 11–12 (2014) (“Depend‐

ing on the particular features of the surveillance device and

how they are configured by the operator, IMSI catchers can be

used to identify nearby phones, locate them with extraordi‐

nary precision, intercept outgoing calls and text messages, as

well as block service, either to all devices in the area or to par‐

ticular devices.” (footnotes omitted)). Because many third‐

party apps automatically send and receive data through the

subscriber’s network, it is reasonable to assume that a Sting‐

ray can collect other information from a cell phone, as well.  

We know nothing about the way in which the Stingray

used in Patrick’s case was configured, nor do we know the

extent of its surveillance capabilities. The majority properly
No. 15‐2443 13

notes that DOJ’s description may or may not be accurate, ei‐

ther in general or for particular cases. It is worth underscoring

how inaccurate that description may be and how important it

is, both for Patrick and as a matter of Fourth Amendment ju‐

risprudence and public policy, that these questions be ex‐

plored.

In this case, the location warrant authorized only methods

of fixing Patrick’s location that involved gathering infor‐

mation that would reveal his phone’s connection with cell‐

phone towers. The Supreme Court has recognized that a

search of cell‐phone data requires a warrant. See Riley v. Cali‐

fornia, 134 S. Ct. 2473, 2494–95 (2014) (associating a warrant‐

less search of a cell phone with the “reviled ‘general warrants’

and ‘writs of assistance’” against which the Fourth Amend‐

ment was aimed). The authorization of the collection of loca‐

tion data cannot be expanded to permit a search of the con‐

tents of Patrick’s cell phone. If the Stingray gathered infor‐

mation from the phone that went beyond his location, such a

“search” of his phone would have been unauthorized, and

suppression of the additional information (which might have

pinpointed Patrick’s location) would likely be required. See

United States v. Foster, 100 F.3d 846, 850–51 (10th Cir. 1996)

(applying blanket suppression where agents performed gen‐

eral search of residence and seized “anything of value” even

though warrant authorized only search for four firearms and

marijuana).  

Title III may also be pertinent here, depending on what the

facts reveal about the device that was used. It seems clear that

if the MPD intercepted any cell‐phone conversations, text

messages, or data, Title III covered those interceptions. Under

section 2511(a), any person who “intentionally intercepts ...
14 No. 15‐2443

any wire, oral, or electronic communication” without follow‐

ing the proper procedures is liable under the statute. “Title III

now applies to the interception of conversations over both cel‐

lular and cordless phones.” Bartnicki v. Vopper, 532 U.S. 514,

524 (2001). The Act defines “electronic communication” as

“any transfer of signs, signals, writing, images, sounds, data,

or intelligence of any nature transmitted in whole or in part

by a wire,radio, electromagnetic, photoelectronic or photoop‐

tical system that affects interstate or foreign commerce.” 18

U.S.C. § 2510(12). Text messages and cell‐phone data trans‐

missions easily fit that definition. None of the relevant excep‐

tions to that definition applies, see id., and there is no reason

to think that the interception of text messages or data trans‐

missions would otherwise be excluded from it. See Brown v.

Waddell, 50 F.3d 285, 289 (4th Cir. 1995) (“The principal pur‐

pose of the [Electronic Communications Privacy Act] amend‐

ments to Title III was to extend to ‘electronic communications’

the same protections against unauthorized interceptions that

Title III had been providing for ‘oral’ and ‘wire’ communica‐

tions via common carrier transmissions.”); see also Joffe v.

Google, Inc., 746 F.3d 920, 930 (9th Cir. 2013) (electronic infor‐

mation transmitted over Wi‐Fi network does not fit 18 U.S.C.

§ 2511(g) exceptions).

The MPD concededly never followed the procedures re‐

quired for an order for electronic surveillance. See 18 U.S.C.

§ 2518. Any interception of the substance of Patrick’s commu‐

nications would thus almost certainly be illegal. The remedy

for a Title III violation is normally the suppression of the ille‐

gally intercepted communications and any evidence derived

from them. 18 U.S.C. § 2515. If such evidence is relevant to

Patrick’s conviction, Title III might require suppression and,
No. 15‐2443 15

in the absence of the suppressed evidence, a reversal of the

conviction.  

Even if the Stingray did not gather any information from

Patrick’s cell phone other than its location, its use still might

be problematic. The court order authorized “cellular tele‐

phone global positioning system (GPS) location information

... if available,” and the “identification of the physical location

of the target cellular telephone.” But that is not all it said: it

specified in some detail the manner in which that information

was to be collected—from the service provider. “Such service

provider,” it stated, “shall initiate a signal to determine the

location of the subject’s mobile device on the service pro‐

vider’s network or with such other reference points as may be

reasonably available[.]” It “[a]pprove[d] the release of infor‐

mation,” not the use of a device that would allow the MPD to

track Patrick’s phone on its own. While it also “authorize[d]

the identification of the physical location of the target cellular

phone,” the context implied that the identification would be

derived from information released by a service provider. I

take these limitations, built into the warrant, seriously; they

circumscribe the authority granted by the warrant just as

surely as a physical limitation to the house but not the garage,

or vice versa, would do.

At oral argument, the government argued that the warrant

authorized it to obtain Patrick’s location with no restrictions

on how it went about accomplishing that task. It relies on Da‐

lia v. United States, 441 U.S. 238, 257 (1979), which held that a

warrant was not defective for lack of particularity where it

authorized police officers to install an electronic listening de‐

vice in the defendant’s office but did not specify that the of‐

ficers would covertly enter the premises to do so. Dalia noted
16 No. 15‐2443

that “the specificity required by the Fourth Amendment does

not generally extend to the means by which warrants are ex‐

ecuted.” Id. But that statement must be understood in context.

Here, the device itself is what is at issue. Because of its capa‐

bilities, the way it was used could affect the scope and loca‐

tion of the search itself.  

We are in all likelihood not looking at two interchangeable

tools for gathering exactly the same information. If the facts

ultimately show that the MPD had gathered the identical in‐

formation in the same manner that Sprint would have used, I

would concede that there is no problem. In such a case, the

only difference between using the Stingray and obtaining the

information from Sprint would be who gathered the infor‐

mation. And the majority may even be correct that the gov‐

ernment’s regrettable lack of candor about the manner of the

search is not enough by itself to render the search unconstitu‐

tional. Under these circumstances, there would be no addi‐

tional privacy intrusion from the use of the Stingray, and the

misrepresentation would not affect whether there was proba‐

ble cause for the search. See United States v. Mittelman, 999

F.2d 440, 444 (9th Cir. 1993) (holding that because “only false

statements that are material in causing the warrant to issue

will invalidate it,” “misstatements regarding the manner of a

search do not bear on the issue of whether the search itself

was justified” under the Fourth Amendment (quoting United

States v. Ippolito, 774 F.2d 1482, 1485 (9th Cir. 1985))); see also

Franks v. Delaware, 438 U.S. 154, 156 (1978) (warrant based in

part on false statements is void if “with the affidavit’s false

material set to one side, the affidavit’s remaining content is

insufficient to establish probable cause”). This means that the

critical questions in a case such as this one, where a much

more sophisticated device is used, are how the Stingray was
No. 15‐2443 17

used, how it works, and whether, conceptually, it “searched”

Patrick’s phone in the same manner that Sprint would or

much more intrusively.

According to extra‐record information provided by amici,

the Stingray is different in kind, not just in degree. On this

record, we do not have sufficient information to say whether

that is right or wrong. We do not know whether the warrant’s

authorization of Sprint to “initiate a signal to determine the

location of the subject’s mobile device on the service pro‐

vider’s network or with such other reference points as may be

reasonable available” also describes the working of the Sting‐

ray that was used. If so, perhaps all is well. If the Stingray

works in a different manner—for instance, by forcing the cell

phone to transmit location data housed inside the cell phone

ratherthan using a signal to locate the cell phone on the Sprint

network—it might not. See C. Justin Brown & Kasha M. Leese,

Stingray Devices Usher in A New Fourth Amendment Battle‐

ground, 39 CHAMPION 12, 14 (2015) (arguing that cell‐site sim‐

ulators engage in “electronic ... intrusion” possibly constitut‐

ing trespass because they force cell phones to transmit infor‐

mation that they would not otherwise). The relevant point is

that a location warrant does not (without saying more) au‐

thorize a search of the contents of the cell phone itself. If that

is the right way to describe what the Stingray did, its use

would constitute an impermissible search, and the gun would

be fruit of the poisonous tree. At this point, we do not have

the facts to say.

My colleagues finally dismiss my concerns for a different

reason: they contend that the existence of a warrant for Pat‐

rick’s arrest brings this case under the rule of Utah v. Strieff,
18 No. 15‐2443

136 S. Ct. 2056 (2016), and precludes the application of the ex‐

clusionary rule. In Strieff, the Supreme Court held that a valid,

pre‐existing arrest warrant could attenuate the link between

an unlawful investigatory stop and evidence seized as a result

of that stop. Id. at 2062. But I do not read Strieff so broadly.  

It is critical in this connection to recall that Strieff rests on

the idea of a break in the causal chain, and it is that break that

attenuates any Fourth Amendment concerns. In Strieff, the of‐

ficer stopped the defendant without reasonable suspicion and

then conducted a warrant check; based on the warrant he dis‐

covered, he arrested the defendant. Id. at 2060. The drugs at

issue were found by the search incident to that arrest. Id. As a

result, the causal chain between the officer’s illegal action—

the initial, unjustified Terry stop—and the search was

“brok[en]” by the intervening discovery of the warrant. Id. at

2063. The arrest warrant was “downstream” of the tainting

action, and “upstream” of the search.  

Our case presents a different sequence. The arrest warrant

here (and the relevant officers’ awareness of it) preceded both

the potentially illegal action and the potentially valid

search—it was “upstream” of both. The MPD got the arrest

warrant, got the location warrant, used the Stingray to locate

Patrick, and then found the gun in plain view in the process

of arresting him. The arrest warrant is therefore not an inter‐

vening cause, at least in the temporal sense. One could per‐

haps argue that the arrest warrant resurfaced in the causal

chain at the moment the MPD located Patrick, and then

moved to apprehend him. (Ironically, in this case, an arrest

warrant was not even necessary to authorize the finding of

the gun, which was in plain view.) But any causal connection
No. 15‐2443 19

in this case between a potentially illegal search and the dis‐

covery of Patrick’s gun had to do with the timing of the

search—not whether the search could be conducted at all. As

a result, the arrest warrant did not do anything to attenuate

the potential taint.  

I recognize that Strieff contains language that could be

stretched to suggest that a warrant’s existence, regardless of

the actual causal chain, is sufficient attenuation. See id. at 2062

(“The Segura Court suggested that the existence of a valid

warrant favors finding that the connection between unlawful

conduct and the discovery of evidence is ‘sufficiently attenu‐

ated to dissipate the taint.’ That principle applies here.” (cita‐

tion omitted)). But elsewhere in the opinion the Court empha‐

sized not only that the “warrant was valid” and “predated

[the officer’s] investigation,” but also that it “was entirely un‐

connected with the stop,” and that the officer’s decision to ar‐

rest the defendant was “a ministerial act that was inde‐

pendently compelled by the pre‐existing warrant.” Id. (em‐

phasis added). Here, the use of the Stingray led to the arrest,

and neither the arrest nor the search was a ministerial act.  

It oversimplifies Strieff to focus solely on whether an inter‐

vening circumstance can be identified. That is important, but

it is not enough by itself. Strieff, like all attenuation cases, also

rests on two other factors: (1) the “temporal proximity” be‐

tween the potentially unlawful action and the “search,” and

(2) the culpability of the police misconduct. Id. As in Strieff,

the relative temporal proximity in our case between the po‐

tentially illegal conduct and the search weighs against atten‐

uation. But unlike the situation in Strieff, the facts here do not

permit us to say that the MPD’s conduct was merely negli‐
20 No. 15‐2443

gent: the police knew what they were doing. Purposeful eva‐

sion of judicial oversight of potentially illegal searches is ex‐

actly the kind of “police misconduct ... most in need of deter‐

rence.” Id. at 2063 (noting that exclusion should be applied

where misconduct is “purposeful or flagrant”). I would find

that all three factors identified in Strieff weigh against finding

attenuation in this case.  

None of the other doctrines that might counsel against use

of the exclusionary rule applies here. Although the independ‐

ent‐source doctrine precludes the operation of the exclusion‐

ary rule, see Murray v. United States, 487 U.S. 533, 537 (1988),

there was no alternate source here that enabled the MPD to

find Patrick. Nor is this case a likely candidate for the inevita‐

ble‐discovery rule. See Nix v. Williams, 467 U.S. 431, 444 (1984)

(exclusionary rule does not apply if “prosecution can estab‐

lish by a preponderance of the evidence that the information

ultimately or inevitably would have been discovered by law‐

ful means”). Patrick’s gun was found because it was in the car

where he was sitting at the time of his apprehension. If not for

the Stingray, he might not have been apprehended in his ve‐

hicle, or he might have been apprehended at a time when the

gun was not located in his vehicle.  

Neither would the good‐faith exception apply. “The good‐

faith exception precludes application of the exclusionary rule

when law enforcement reasonably and in good faith believed

that a search was lawful.” United States v. Tomkins, 782 F.3d

338, 349 (7th Cir. 2016) (citing United States v. Leon, 468 U.S.

897, 922 (1984)). The contents of the search warrant applica‐

tion, the warrant itself, and the government’s litigation of this

case all tend to show that the officers deliberately deceived
No. 15‐2443 21

the issuing judge about how they planned to execute the war‐

rant. While the test for the exception is “an objective one,”

Leon, 468 U.S. at 919 n.20, that fact is designed to safeguard

the Fourth Amendment’s substantive protections, not to limit

them. See id. at 915 n.13. Deception of the issuing magistrate

is just the kind of misconduct “sufficiently deliberate that ex‐

clusion can meaningfully deter it, and sufficiently culpable

that such deterrence is worth the price paid by the justice sys‐

tem.” Herring v. United States, 555 U.S. 135, 144 (2009). Leon

specifically noted that the good‐faith exception should not ap‐

ply “when the affiant misleads the magistrate with a reckless

or knowing disregard for the truth.” United States v. Glover,

755 F.3d 811, 818 (7th Cir. 2014) (citing Leon, 468 U.S. at 914

(suppression appropriate where officers dishonest in prepar‐

ing affidavit)).  

A number of other courts have suggested that bad faith,

especially when manifested by insufficient candor to the issu‐

ing magistrate, may justify suppression. See United States v.

Sells, 463 F.3d 1148, 1161 n.7 (10th Cir. 2006) (noting that “a

number of courts have concluded that the severance doctrine

is not applicable where the Government has added particu‐

larized descriptions of items to be seized for which probable

cause exists as a pretext to support an otherwise unlawful

search and seizure”); United States v. Woerner, 709 F.3d 527,

534 (5th Cir. 2013) (collecting cases for principle that suppres‐

sion is appropriate where the “officer applying for the war‐

rant knew or had reason to know that the information was

tainted and included it anyway without full disclosure and

explanation”); United States v. Reilly, 76 F.3d 1271, 1281 (2d

Cir. 1996) (rejecting application of good‐faith exception

“when the officers are themselves ultimately responsible for

the defects in the warrant”). Although these cases are about
22 No. 15‐2443

affidavits supporting probable cause, their logic applies

equally to the execution of the search. After all, the Leon ex‐

ception was meant to prevent the “[p]enalizing [of] the officer

for the magistrate’s error,” Leon, 468 U.S. at 921, and to “allow

some latitude for honest mistakes.” Maryland v. Garrison, 480

U.S. 79, 87 (1987). If the MPD misled the magistrate or reason‐

ably should have known that the warrant did not cover a

Stingray, neither concern applies here.  

Even if my colleagues’ reading of Strieff were correct or

another doctrine precluding the exclusionary rule applied,

those facts would not resolve any potential Title III issues dis‐

covery could reveal. Our sister circuits disagree about

whether the Title III suppression remedy is affected by the

judge‐made exclusionary rule. Compare United States v. Rice,

478 F.3d 704, 711 (6th Cir. 2007) (good‐faith exception does

not apply); United States v. Spadaccino, 800 F.2d 292, 296 (2d

Cir. 1986) (using this same rationale and reaching the same

conclusion in analyzing whether the Leon good‐faith excep‐

tion applied to a state wiretapping statute); United States v.

Vest, 813 F.2d 477, 484 (1st Cir. 1987) (rejecting judicially cre‐

ated exception); with United States v. Moore, 41 F.3d 370, 376

(8th Cir. 1994) (good‐faith exception applies); United States v.

Malekzadeh, 855 F.2d 1492, 1497 (11th Cir. 1988) (same, alt‐

hough without analysis); United States v. Brewer, 204 Fed.

App’x 205, 208 (4th Cir. 2006) (same). No court of appeals has

found that the attenuation rule applies to the Title III suppres‐

sion remedy. In fact, United States v. Giordano, 416 U.S. 505,

528 (1974), seems to suggest it does not. Unless we are pre‐

pared to weigh in on this question without knowing whether

it is before us, we should remand for further fact‐finding.  
No. 15‐2443 23

It is time for the Stingray to come out of the shadows, so

that its use can be subject to the same kind of scrutiny as other

mechanisms, such as thermal imaging devices, GPS trackers,

pen registers, beepers, and the like. Its capabilities go far be‐

yond any of those, and cases such as Riley indicate that the

Supreme Court might take a dim view of indiscriminate use

of something that can read texts and emails, listen to conver‐

sations, and perhaps intercept other application data housed

not just on the target’s phone, but also on those of countless

innocent third parties. Governmental entities, including the

Justice Department itself, see DOJ Policy Guidance, ante at 3–

4, and the State of Illinois, see Citizen Privacy Protection Act,

Pub. Act 099‐0622 (2016) (delineating court order, disclosure,

and minimization requirements for police use of cell‐site sim‐

ulators), have recognized the weighty Fourth Amendment

concerns the device provokes. It is possible that discovery

could reveal that none of those concerns is triggered in this

case. But before we dismiss them, we should have all the facts

before us. For that reason, I would remand this case for fur‐

ther fact‐finding. I respectfully dissent.