FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,

Plaintiff-Appellee,

v.

MIGUEL ANGEL CANO,

Defendant-Appellant.

No. 17-50151

D.C. No.

3:16-cr-01770-BTM-1

OPINION

Appeal from the United States District Court

for the Southern District of California

Barry Ted Moskowitz, District Judge, Presiding

Argued and Submitted April 10, 2019

Pasadena, California

Filed August 16, 2019

Before: Susan P. Graber and Jay S. Bybee, Circuit Judges,

and M. Douglas Harpool,* District Judge.

Opinion by Judge Bybee

*

 The Honorable M. Douglas Harpool, United States District Judge

for the Western District of Missouri, sitting by designation
2 UNITED STATES V. CANO

SUMMARY**

Criminal Law

The panel reversed the district court’s order denying the

defendant’s motion to suppress evidence obtained from

warrantless searches of his cell phone byCustoms and Border

Protection officials, and vacated his conviction for importing

cocaine.

Applying United States v. Cotterman, 709 F.3d 952 (9th

Cir. 2013) (en banc), the panel held that manual cell phone

searches may be conducted by border officials without

reasonable suspicion but that forensic cell phone searches

require reasonable suspicion. The panel clarified Cotterman

by holding that “reasonable suspicion” in this context means

that officials must reasonably suspect that the cell phone

contains digital contraband. The panel further concluded that

cell phone searches at the border, whether manual or forensic,

must be limited in scope to whether the phone contains digital

contraband; and that a broader search for evidence of a crime

cannot be justified by the purposes of the border search

exception to the Fourth Amendment warrant requirement.

The panel held that to the extent that a Border Patrol

agent’s search of the defendant’s phone – which included the

recording of phone numbers and text messages for further

processing – went beyond a verification that the phone lacked

digital contraband, the search exceeded the proper scope of a

border search and was unreasonable as a border search under

** This summary constitutes no part of the opinion of the court. It has

been prepared by court staff for the convenience of the reader.
UNITED STATES V. CANO 3

the Fourth Amendment. The panel held that although the

agents had reason to suspect the defendant’s phone would

contain evidence leading to additional drugs, the record does

not give rise to an objectively reasonable suspicion that the

digital data in the phone contained contraband, and the border

search exception therefore did not authorize the agents to

conduct a warrantless forensic search of the defendant’s

phone. The panel held that the good faith exception to the

exclusionary rule does not apply because the border officials

did not rely on binding appellate precedent specifically

authorizing the cell phone searches at issue here.

Rejecting the defendant’s contention that the government

violated his rights under Brady v, Maryland, 373 U.S. 83

(1963), and Fed. R. Crim. P. 16, by failing to turn over certain

information he requested from the FBI and DEA in pursuit of

this third-party defense, the panel found no evidence that the

prosecution had knowledge or possession of evidence

showing that the defendant’s cousin or his cousin’s gang were

involved in drug trafficking at the Mexico-California border,

and held that the prosecutor should not be held to have

“access” to any information that an agency not involved in

the investigation or prosecution of the case refuses to turn

over.
4 UNITED STATES V. CANO

COUNSEL

Harini P. Raghupathi (argued), Federal Defenders of San

Diego, Inc., San Diego, California, for Defendant-Appellant.

Mark R. Rehe (argued), Assistant United States Attorney;

Helen H. Hong, Assistant United States Attorney, Chief,

Appellate Section, Criminal Division; Adam L. Braverman,

United States Attorney; United States Attorney’s Office, San

Diego, California; for Plaintiff-Appellee.

Sophia Cope and Adam Schwartz, Electronic Frontier

Foundation, San Francisco, California, for Amicus Curiae

Electronic Frontier Foundation.

OPINION

BYBEE, Circuit Judge:

Defendant-Appellant Miguel Cano was arrested for

carrying cocaine as he attempted to cross into the United

States from Mexico at the San Ysidro Port of Entry. 

Following his arrest, a Customs and Border Protection

official seized Cano’s cell phone and searched it, first

manually and then using software that accesses all text

messages, contacts, call logs, media, and application data. 

When Cano moved to suppress the evidence obtained from

the warrantless searches of his cell phone, the district court

held that the searches were valid under the border search

exception to the Fourth Amendment’s warrant requirement.

Applying United States v. Cotterman, 709 F.3d 952 (9th

Cir. 2013) (en banc), we conclude that manual cell phone
UNITED STATES V. CANO 5

searches may be conducted by border officials without

reasonable suspicion but that forensic cell phone searches

require reasonable suspicion. We clarify Cotterman by

holding that “reasonable suspicion” in this context means that

officials must reasonably suspect that the cell phone contains

digital contraband. We further conclude that cell phone

searches at the border, whether manual or forensic, must be

limited in scope to a search for digital contraband. In this

case, the officials violated the Fourth Amendment when their

warrantless searches exceeded the permissible scope of a

border search. Accordingly, we hold that most of the

evidence from the searches of Cano’s cell phone should have

been suppressed. We also conclude that Cano’s Brady claims

are unpersuasive. Because we vacate Cano’s conviction, we

do not reach his claim of prosecutorial misconduct.

We reverse the district court’s order denying Cano’s

motion to suppress and vacate Cano’s conviction.

I. THE BACKGROUND

A. The Facts

Defendant-Appellant Miguel Cano worked in the flooring

and carpet installation trade and lived with his wife and

children in the Mission Hills community north of Los

Angeles. In the summer of 2016, however, Cano moved from

Los Angeles to Tijuana, Mexico, where he stayed with his

cousin Jose Medina. While staying with Medina, Cano

crossed the border into the United States six times, sometimes

remaining in the United States for less than thirty minutes. 

On two of those trips, Cano was referred to secondary

inspection, but no contraband was found. 
6 UNITED STATES V. CANO

On July 25, 2016, Cano arrived at the San Ysidro Port of

Entry from Tijuana. In primary inspection, Cano stated that

“he was living in Mexico, working in San Diego, but going to

LA on that day.” Pursuant to a random Customs and Border

Protection (CBP) computer referral, Cano was referred to

secondary inspection, where a narcotic-detecting dog alerted

to the vehicle’s spare tire. A CBP official removed the spare

tire from the undercarriage of the truck and discovered 14

vacuum-sealed packages inside, containing 14.03 kilograms

(30.93 pounds) of cocaine.

Cano was arrested, and a CBP official administratively

seized his cell phone. The CBP officials called Homeland

Security Investigations (HSI), which dispatched Agents

Petonak and Medrano to investigate. After arriving, Agent

Petonak “briefly” and manually reviewed Cano’s cell phone,

noticing a “lengthy call log” but no text messages. Agent

Petonak later stated that the purpose of this manual search

was “two-pronged”: “to find some brief investigative leads in

the current case,” and “to see if there’s evidence of other

things coming across the border.”

Agent Petonak proceeded to question Cano, who waived

his Miranda rights and agreed to talk. During that interview,

Cano denied any knowledge of the cocaine. Cano stated that

he had moved to Tijuana to look for work in nearby San

Diego, because work was slow in Los Angeles. He also said

he had crossed the border every day for the previous three

weeks looking for work. He told Agent Petonak that he was

headed to a carpet store in Chula Vista that day to seek work. 

When pressed, Cano was not able to provide the name or

address of the store, claiming that he intended to look it up on

Google after crossing the border. Cano also explained that he

did not have his flooring tools with him in his pickup truck so
UNITED STATES V. CANO 7

as to avoid problems with border crossings; Cano intended to

drive to Los Angeles to retrieve his tools if he located work

in San Diego.

During the interrogation, Agent Petonak specifically

asked Cano about the lack of text messages on his cell phone. 

Cano responded that his cousin had advised him to delete his

text messages “just in case” he got pulled over in Mexico and

police were to check his cell phone. Cano stated that he

erased his messages to avoid “any problems” with the

Mexican police.

While Agent Petonak questioned Cano, Agent Medrano

conducted a second manual search of the cell phone. Agent

Medrano browsed the call log and wrote down some of the

phone numbers on a piece of paper. He also noticed two

messages that arrived after Cano had reached the border, and

he took a photograph of the messages. The first message

stated, “Good morning,” and the second message stated,

“Primo, are you coming to the house?” Agent Medrano gave

all of this information—the recorded list of calls and the

photograph—to Agent Petonak.

Finally, Agent Medrano conducted a “logical download”

of the phone using Cellebrite software. A Cellebrite search

enables the user to access text messages, contacts, call logs,

media, and application data on a cell phone and to select

which types of data to download. It does not, however, allow

the user to access data stored within third-party applications. 

Agent Medrano typically does not select the option to

download photographs. 

After Agent Petonak interviewed Cano, he reviewed the

results of the Cellebrite download of Cano’s phone by Agent
8 UNITED STATES V. CANO

Medrano. The Cellebrite results revealed that Cano had sent

no text messages, and it listed all the calls made by Cano. 

Agent Petonak later concluded that none of the phone

numbers in the call log corresponded to carpeting stores in

San Diego.

B. The Proceedings

Cano was indicted for importing cocaine. Before trial,

Cano moved to suppress any evidence obtained from Agents

Petonak and Medrano’s warrantless searches of his cell phone

at the border. The district court denied Cano’s motion, ruling

that the manual searches and the Cellebrite search of Cano’s

phone were valid border searches. During trial, the

government introduced evidence that resulted from the

manual searches of the phone and from Agent Medrano’s

Cellebrite download of the phone.1

In preparation for trial, Cano indicated his intent to

present a third-party culpability defense claiming that his

cousin, Jose Medina, was responsible for placing the drugs in

Cano’s spare tire without Cano’s knowledge. Cano proffered

evidence that Medina had a key to Cano’s car and had driven

it shortly before Cano’s attempted border crossing, that

1 Some—but not all—of the evidence was available through

alternative channels. For example, the government introduced a call log,

unchallenged by Cano, that the government received from Cano’s phone

company. Similarly, the government later obtained a warrant to search the

phone, and an agent conducted further searches. Because the government

introduced at trial much evidence pre-dating those events, and because the

government has not argued that any Fourth Amendment error was

harmless, those later events do not affect our Fourth Amendment analysis

of the warrantless searches. United States v. Rodriguez, 880 F.3d 1151,

1163 (9th Cir. 2018)
UNITED STATES V. CANO 9

Medina had a criminal record including a conviction for

cocaine possession, that Medina was a member of a Chicagobased gang called the Latin Kings, and that the Latin Kings

sold cocaine within the United States and were involved with

a cartel that trafficked drugs across the border. 

FollowingCano’s implication of Medina, the government

contacted Medina and promised him immunity and

immigration papers in exchange for his cooperation. Medina

initially denied being involved with drugs, but later contacted

the government on his own and offered to help them with the

“biggest RICO case” and “drug seizures of 20 to 25

kilograms at a time.” All of this information was made

available to Cano.

As part of his defense, Cano sought additional discovery

from HSI, the Federal Bureau of Investigation (FBI), and the

Drug Enforcement Agency (DEA) regarding: (1) records

linking Medina to drug sales, distribution, or trafficking; and

(2) records linking the Latin Kings to drug trafficking from

Mexico to Southern California. The government opposed

Cano’s discovery motion, arguing that the evidence was not

material under Federal Rule of Criminal Procedure

16(a)(1)(E)(i) and that discovery should be limited to HSI, as

neither the DEA nor the FBI had participated in the

investigation of Cano. The district court originally overruled

both objections, finding the evidence material under Rule 16

and exculpatory under Brady v. Maryland, 373 U.S. 83

(1963). The court also reasoned that, because HSI could

inquire of the DEA and FBI if it sought inculpatory evidence,

HSI had access to the files and was required to provide any

exculpatory evidence held by the DEA or FBI.
10 UNITED STATES V. CANO

In response to the court’s discovery order, HSI produced

Medina’s immigration file and his Bureau of Prisons record. 

Agent Petonak also searched for Medina’s name in two

different police clearinghouses, but neither returned any hits.2

Both Agent Petonak and the United States Attorney’s Office

(USAO) subsequently requested information showing a link

between the Latin Kings and drug trafficking from Mexico

from the legal counsel of both the FBI and DEA. Both

agencies denied the requests without providing any

explanation or any indication as to whether the requested

information existed.

Following these attempts, the government moved for the

district court to reconsider its discovery order and excuse it

from discovery relating to files held by the FBI and DEA. 

The district court granted the motion to reconsider, finding

that the prosecutor did not have access to the evidence when

he was “rebuffed” by agencies over which he had no control.

The case proceeded to trial and Cano presented his thirdparty culpability defense. The first trial resulted in a hung

jury and a mistrial. On retrial, Cano again relied on his thirdparty culpability defense. The second trial resulted in Cano’s

conviction. This appeal followed, in which Cano raises three

issues: (1) whether the warrantless searches of his cell phone

violated the Fourth Amendment and whether the resulting

evidence should be suppressed; (2) whether the government’s

non-disclosure of materials that may have been held by the

DEA and FBI violated his right to due process under Brady

2 A police clearinghouse works for the purpose of “deconfliction” by

notifying an agency if another agency has an investigation pending against

the same person or item. The DEA and FBI participate in the two

clearinghouses searched by Agent Petonak.
UNITED STATES V. CANO 11

and Federal Rule of Criminal Procedure 16; and (3) whether

the government raised an improper propensity inference in its

closing argument. We address Cano’s first two arguments in

turn. Because we conclude that the district court erred in

denying Cano’s motion to suppress, we vacate Cano’s

conviction and do not reach his claim of prosecutorial

misconduct.

II. THE WARRANTLESS SEARCH OF CANO’S

CELL PHONE

The Fourth Amendment protects “[t]he right of the people

to be secure in their persons, houses, papers, and effects,

against unreasonable searches and seizures.” U.S. Const.

amend. IV.3 Ordinarily, before conducting a search, police

must obtain a warrant issued by a judicial officer 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.” Id. Warrants are generally

required “unless ‘the exigencies of the situation’ make the

needs of law enforcement so compelling that the warrantless

search is objectively reasonable under the Fourth

Amendment.” Mincey v. Arizona, 437 U.S. 385, 393–94

(1978) (citation omitted). Consequently, “searches conducted

outside the judicial process, without prior approval by judge

or magistrate, are per se unreasonable under the Fourth

Amendment—subject only to a few specifically established

and well-delineated exceptions.” Katz v. United States, 389

U.S. 347, 357 (1967) (footnote omitted). Such “specifically

established and well-delineated exceptions” include exigent

3 We review de novo “the district court’s determination that [a]

warrantless search . . . was a valid border search.” United States v.

Cardona, 769 F.2d 625, 628 (9th Cir. 1985). 
12 UNITED STATES V. CANO

circumstances, searches incident to arrest, vehicle searches,

and border searches. See Arizona v. Gant, 556 U.S. 332, 343

(2009) (vehicle searches); Brigham City v. Stuart, 547 U.S.

398, 403 (2006) (exigent circumstances; listing other

exceptions, including warrantless entry to fight a fire, to

prevent the imminent destruction of evidence, or in “hot

pursuit” of a fleeing suspect); United States v. Ramsey, 431

U.S. 606, 616 (1977) (border searches); Weeks v. United

States, 232 U.S. 383, 392 (1914) (searches incident to arrest),

overruled in part on other grounds by Mapp v. Ohio, 367

U.S. 643 (1961).

Exceptions to the warrant requirement are subject to two

important constraints. First, any search conducted under an

exception must be within the scope of the exception. Second,

some searches, even when conducted within the scope of the

exception, are so intrusive that they require additional

justification, up to and including probable cause and a

warrant.

The first constraint is illustrated by the Supreme Court’s

decision in Riley v. California, 573 U.S. 373 (2014), a case

involving the search incident to arrest exception. In Riley, the

Court addressed “whether the police may, without a warrant,

search digital information on a cell phone seized from an

individual who has been arrested”; in other words, whether

cell phones fell within the scope of the search incident to

arrest exception. Id. at 378. The Court began by recognizing

the increasing role in our lives of “minicomputers that also

happen to have the capacity to be used as a telephone”;

“[m]odern cell phones, as a category, implicate privacy

concerns far beyond those implicated by the search of a

cigarette pack, a wallet, or a purse.” Id. at 393. 

Acknowledging that “it has been well accepted that [a search
UNITED STATES V. CANO 13

incident to lawful arrest] constitutes an exception to the

warrant requirement,” id. at 382, the Court pointed out that

such searches serve two purposes: (1) to secure “the officer’s

safety” and (2) to “prevent . . . concealment or destruction [of

evidence],” id. at 383 (citation omitted). The Court then

considered whether a cell phone search qualified as a search

incident to arrest by considering “whether application of the

search incident to arrest doctrine to [cell phones] would

‘untether the rule from the justifications underlying the . . .

exception.’” Id. at 386 (quoting Gant, 556 U.S. at 343). 

The Court concluded that neither purpose for the search

incident to arrest exception justified the search of a cell

phone. The Court rejected the government’s argument that

searching a cell phone incident to arrest would “help ensure

officer safety in . . . indirect ways, for example by alerting

officers that confederates of the arrestee are headed to the

scene.” Id. at 387. The Court reasoned that the government’s

position “would . . . represent a broadening” of the

exception’s foundational concern that “an arrestee himself

might grab a weapon and use it against an officer.” Id. at

387–88. The Court observed that “once law enforcement

officers have secured a cell phone, there is no longer any risk

that the arrestee himself will be able to delete incriminating

data from the phone,” id. at 388, and police have means to

ensure that data cannot be wiped from the phone remotely, 

id. at 390. The Court concluded “not that the information on

a cell phone is immune from search; [but rather] that a

warrant is generally required before such a search, even when

a cell phone is seized incident to arrest.” Id. at 401.

The second constraint on warrantless searches is

illustrated by the Court’s decision in United States v.

Montoya de Hernandez, 473 U.S. 531 (1985). Montoya was
14 UNITED STATES V. CANO

stopped at Los Angeles International Airport and referred to

secondary inspection. Id. at 533. She had arrived from

Bogota and was carrying $5,000 in cash. Id. She had no

credit cards and no hotel reservations. Id. at 533–34. 

Because border officials suspected that Montoya may have

swallowed cocaine-filled balloons, Montoya was held in the

customs office and, after a magistrate judge issued an order,

taken to a hospital for a rectal examination. Id. at 534–35. 

Over the next four days, she passed 88 balloons containing

cocaine. Id. at 536. Montoya argued that the search she was

subjected to, though a border search, was so intrusive that it

could not be conducted without a high level of particularized

suspicion. Id. at 536–37, 540. The Court balanced her

privacy interests against the interests of the government at the

border and concluded that, while routine searches may be

conducted at the border without any showing of suspicion, a

more intrusive, nonroutine search must be supported by

“reasonable suspicion.” Id. at 537–41; see also United States

v. Flores-Montano, 541 U.S. 149, 152 (2004) (suggesting that

nonroutine searches are limited to “highly intrusive searches

of the person” involving “dignity and privacy interests”).

Cano recognizes that he was subject to search at the

border, but Cano and amicus Electronic Frontier Foundation

(“EFF”) raise two categorical challenges and one as-applied

challenge to the searches conducted here. First, EFF argues

that any warrantless search of a cell phone falls outside the

scope of the border search exception. Second, EFF argues

that even if the search is within the scope of the border search

exception, a warrantless cell phone search is so intrusive that

it requires probable cause. We address these categorical

challenges in Part II.A. Third, Cano asserts that, even if cell

phones are generally subject to search at the border, the

manual and forensic searches of his cell phone exceeded the
UNITED STATES V. CANO 15

“well delineated” scope of the border search. We address this

as-applied question in Part II.B. Finally, the government

argues that even if the border search exceeded the limits of

the Fourth Amendment, the search was conducted in good

faith, and the evidence is admissible. We consider the good

faith exception in Part II.C.

A. Border Searches and Cell Phones

“[B]order searches constitute a ‘historically recognized

exception to the Fourth Amendment’s general principle that

a warrant be obtained.’” Cotterman, 709 F.3d at 957 (quoting

Ramsey, 431 U.S. at 621). Indeed, border searches typically

do not require any particularized suspicion, so long as they

are “routine inspections and searches of individuals or

conveyances seeking to cross our borders.” Almeida-Sanchez

v. United States, 413 U.S. 266, 272 (1973); see United States

v. Seljan, 547 F.3d 993, 999 (9th Cir. 2008) (en banc). Such

searches are “reasonable simply by virtue of the fact they

occur at the border.” Ramsey, 431 U.S. at 616. The

exception is “rooted in ‘the long-standing right of the

sovereign to protect itself by stopping and examining persons

and property crossing into this country,’” Cotterman, 709

F.3d at 960 (quoting Ramsey, 431 U.S. at 616), to “prevent[]

the entry of unwanted persons and effects,” id. (quoting

Flores-Montano, 541 U.S. at 152). 

The sovereign’s right to conduct suspicionless searches at

the border “does not mean, however, that at the border

‘anything goes.’” Id. (quoting Seljan, 547 F.3d at 1000). 

Rather, the border search exception is a “narrow exception”

that is limited in two important ways. Id. (citation omitted). 

First, “[t]he authorizing statute limits the persons who may

legally conduct a ‘border search’ to ‘persons authorized to
16 UNITED STATES V. CANO

board or search vessels.’” United States v. Soto-Soto, 598

F.2d 545, 549 (9th Cir. 1979) (citing 19 U.S.C. § 482).4 This

includes customs and immigration officials, but not general

law enforcement officers such as FBI agents. Id.; see United

States v. Diamond, 471 F.2d 771, 773 (9th Cir. 1973) (stating

that “customs agents are not general guardians of the public

peace”). Second, a border search must be conducted “in

enforcement of customs laws.” Soto-Soto, 598 F.2d at 549.

A border search must be conducted to “enforce importation

laws,” and not for “general law enforcement purposes.” Id.

4

 Section 482 now reads in relevant part: 

Any of the officers or persons authorized to board

or search vessels may stop, search, and examine . . . any

vehicle, beast, or person, on which or whom he or they

shall suspect there is merchandise which is subject to

duty, or shall have been introduced into the United

States in any manner contrary to law . . . . [and may]

seize and secure the same for trial.

19 U.S.C. § 482(a); see id. § 1467 (“[T]he appropriate customs officer for

[a] port or place of arrival may . . . enforce, cause inspection, examination,

and search to be made of the persons, baggage, and merchandise

discharged or unladen from [an arriving] vessel . . . .”); id. § 1496 (“The

appropriate customs officer may cause an examination to be made of the

baggage of any persons arriving in the United States in order to ascertain

what articles are contained therein and whether subject to duty, free of

duty, or prohibited . . . .”); id. § 1582 (“[A]ll persons coming into the

United States fromforeign countries shall be liable to detention and search

by authorized officers or agents . . . .”).

The Court has described § 482 as granting the executive “plenary

authority to conduct routine searches and seizures at the border, without

probable cause or a warrant.” Montoya de Hernandez, 473 U.S. at 537. 

We have held that the “outer limits of authority delegated by [§ 482 are]

available only in border searches.” Corngold v. United States, 367 F.2d

1, 3 (9th Cir. 1966) (en banc). 
UNITED STATES V. CANO 17

A general search cannot be “justif[ied] . . . on the mere basis

that it occurred at the border.” Id. (affirming the suppression

of evidence where an FBI agent stopped and searched the

vehicle of an alien to determine whether the car had been

stolen). 

1. Cell Phone Data as Contraband 

As we discussed briefly above, the Supreme Court has

identified two principal purposes behind warrantless border

searches: First, to identify “[t]ravellers . . . entitled to come

in” and, second, to verify their “belongings as effects which

may be lawfully brought in.” Carroll v. United States, 267

U.S. 132, 154 (1925); see Ramsey, 431 U.S. at 620 (“The

border-search exception is grounded in the recognized right

of the sovereign to control . . . who and what may enter the

country.”). 

EFF argues that applying the border search exception to

a cell phone’s data would “untether” the exception from the

purposes underlying it. EFF contends that a border search

encompasses only a search for illegal persons and physical

contraband located on the body of the applicant for

admission or among his effects. Because digital data on a cell

phone cannot conceal objects such as drugs, guns, or

smuggled persons, EFF asserts that digital cell phone

searches are always beyond the scope of the border search

exception.

We agree with EFF that the purpose of the border search

is to interdict contraband, but we disagree with its premise

that cell phones cannot contain contraband. Although cell
18 UNITED STATES V. CANO

phone data cannot hide physical objects,5the data can contain

digital contraband. The best example is child pornography. 

See United States v. Molina-Isidoro, 884 F.3d 287, 295 n.3

(5th Cir. 2018) (Costa, J., specially concurring) (“One type of

contraband that can be stored within the data of a cell

phone . . . is child pornography.”). And because cell phones

may ultimately be released into the interior, even if the owner

has been detained, the United States has a strong interest in

preventing the entry of such material. See, e.g., United States

v. Vergara, 884 F.3d 1309, 1311 (11th Cir.) (describing how

agents returned one of the defendant’s phones to a family

member after defendant had been arrested for possessing

child pornography on his other two phones), cert. denied, 139

S. Ct. 70 (2018). We find no basis for the proposition that the

border search exception is limited to searching for physical

contraband. At the very least, a cell phone that has photos

stored on it is the equivalent of photographs, magazines, and

books.

6

See Riley, 573 U.S. at 394; Cotterman, 709 F.3d at

964. The contents may be digital when they are on the phone,

but the physicality of the phone itself and the possibility that

5 No one contests that a border official could, consistent with the

Fourth Amendment, examine the physical body of a cell phone to see if

the phone itself is contraband—because, for example, it is a pirated copy

of a patented U.S. phone—or if the phone itself presents a physical threat

to officers. See Riley, 573 U.S. at 387 (“Law enforcement officers remain

free to examine the physical aspects of a phone to ensure that it will not

be used as a weapon—say, to determine whether there is a razor blade

hidden between the phone and its case.”). The dispute here concerns only

whether border officials may search the digital data contained within the

phone. 

6 We need not address here questions surrounding the use of “cloud

computing,” where the phone gives access to, but does not contain in its

own memory, digital data stored in the cloud. See Riley, 573 U.S. at

397–98; Cotterman, 709 F.3d at 965 & n.12. 
UNITED STATES V. CANO 19

the phone’s contents can be printed or shared electronically

gives border officials sufficient reason to inspect it at the

border. We conclude that cell phones—including the phones’

data—are subject to search at the border. 

2. Forensic Cell Phone Searches as an Intrusive Search

The second question we must address in response to

amicus EFF is whether forensic searches of a cell phone are

so intrusive that they require reasonable suspicion or even

probable cause. We answered this question in our en banc

decision in Cotterman, but with respect to laptop computers.7

Cotterman, 709 F.3d at 962–68. Cotterman was a United

States citizen returning to the United States from Mexico. Id.

at 957. When he reached the port of entry, border officials

noted that Cotterman had various convictions for sexual

conduct with children. Id. Concerned that Cotterman might

be involved in child sex tourism, officials conducted a brief

search of his laptop computers and digital cameras and noted

that the laptops had password-protected files. Id. at 958. The

officials detained the computers for several days in order to

run a comprehensive forensic search of the hard drive, which

revealed hundreds of images of child pornography. Id. at

958–59. For us, “the legitimacy of the initial search of

Cotterman’s electronic devices at the border [was] not in

doubt,” id. at 960, “[t]he difficult question . . . [was] the

reasonableness, without a warrant, of the forensic

7 Although Cotterman referred to “electronic devices” generally, see

709 F.3d at 962–68, our holding was limited to the “examination of

Cotterman’s computer,” id. at 968, and did not address cell phones. We

mentioned cell phones only once—in the first paragraph of the

introduction describing the modern “digital world.” Id. at 956. 
20 UNITED STATES V. CANO

examination that comprehensively analyzed the hard drive of

the computer,” id. at 961. 

We acknowledged the “substantial personal privacy

interests” in “[e]lectronic devices . . . capable of storing

warehouses full of information.” Id. at 964. At the same

time, we recognized “the important security concerns that

prevail at the border” and the legitimacy of “[t]he effort to

interdict child pornography.” Id. at 966. We held that a

routine, manual search of files on a laptop computer—“a

quick look and unintrusive search”—is reasonable “even

without particularized suspicion,” but that officials must

“possess a particularized and objective basis for suspecting

the person stopped of criminal activity” to engage in a

forensic examination, which is “essentially a computer strip

search.” Id. at 960–61, 966, 967 (citation omitted). We

concluded that reasonable suspicion was “a modest, workable

standard that is already applied in the extended border search,

Terry stop, and other contexts.” Id. at 966; see id. at 968

(defining reasonable suspicion as “a particularized and

objective basis for suspecting the particular person stopped of

criminal activity” (quoting United States v. Cortez, 449 U.S.

411, 417–18 (1981))).

We think that Cotterman’s reasoning applies equally to

cell phones. In large measure, we anticipated the Supreme

Court’s reasoning in Riley, 573 U.S. at 393–97, when we

recognized in Cotterman that digital devices “contain the

most intimate details of our lives” and “the uniquely sensitive

nature of data on electronic devices carries with it a

significant expectation of privacy,” Cotterman, 709 F.3d at

965–66; see Riley, 573 U.S. at 385, 393 (describing cell

phones as “a pervasive and insistent part of daily life” that,

“as a category, implicate privacy concerns far beyond those
UNITED STATES V. CANO 21

implicated by the search of a cigarette pack, a wallet, or a

purse”). The Court’s view of cell phones in Riley so closely

resembles our own analysis of laptop computers in Cotterman

that we find no basis to distinguish a forensic cell phone

search from a forensic laptop search.8

Nor do we believe that Riley renders the Cotterman

standard insufficiently protective. Riley, of course, held that

“a warrant is generally required” before searching a cell

phone, “even when a cell phone is seized incident to arrest.” 

573 U.S. at 401. But here we deal with the border search

exception—not the search incident to arrest exception—and

the difference in context is critical. In light of the

government’s enhanced interest in protecting the “integrity of

the border” and the individual’s decreased expectation of

privacy, the Court has emphasized that “the Fourth

Amendment’s balance of reasonableness is qualitatively

different at the international border than in the interior” and

is “struck much more favorably to the Government.” 

Montoya de Hernandez, 473 U.S. at 538–40. As a result,

post-Riley, no court has required more than reasonable

suspicion to justify even an intrusive border search. See

United States v. Wanjiku, 919 F.3d 472, 485 (7th Cir. 2019)

(“[N]o circuit court, before or after Riley, has required more

than reasonable suspicion for a border search of cell phones

or electronically-stored data.”); Touset, 890 F.3d at 1234

8 We note that the Eleventh Circuit disagreed with Cotterman in

United States v. Touset, 890 F.3d 1227, 1234 (11th Cir. 2018). The court

held that no level of suspicion was required to conduct a forensic search

of a cell phone. Id. at 1234–35. Nevertheless, the Touset court held, in

the alternative, that the forensic search of various electronic devices seized

at the border were supported by reasonable suspicion. Id. at 1237. As

with most cell phone search cases, in Touset border agents were looking

for child pornography. 
22 UNITED STATES V. CANO

(“Riley, which involved the search-incident-to-arrest

exception, does not apply to searches at the border.”);

Molina-Isidoro, 884 F.3d at 291 (“For border searches both

routine and not, no case has required a warrant.”); id. at 293

(“The bottom line is that only two of the many federal cases

addressing border searches of electronic devices have ever

required any level of suspicion. They both required only

reasonable suspicion and that was for the more intrusive

forensic search.”); see also Kolsuz, 890 F.3d 133, 137 (4th

Cir. 2018) (concluding that a “forensic examination of

Kolsuz’s phone must be considered a nonroutine border

search, requiring some measure of individualized suspicion”

but declining to decide whether the standard should be

reasonable suspicion or probable cause). 

Accordingly, we hold that manual searches of cell phones

at the border are reasonable without individualized suspicion,

whereas the forensic examination of a cell phone requires a

showing of reasonable suspicion. See Cotterman, 709 F.3d

at 968.

B. The Searches of Cano’s Cell Phone and the Scope of the

Border Search Exception

Having concluded that border officials may conduct

suspicionless manual searches of cell phones, but must have

reasonable suspicion before they conduct a forensic search,

we still must address the core of Cano’s argument: whether

the manual and forensic searches of his cell phone were not

searches for digital contraband, but searches for evidence of

a crime, and thus exceeded the proper scope of a border

search.
UNITED STATES V. CANO 23

1. The Border Exception and the Search for Contraband

As a threshold matter, Cano argues that border searches

are limited in both purpose and scope to searches for

contraband.9In response, the government argues that

searches for evidence that would aid in prosecuting past and

preventing future border-related crimes are tethered to the

purpose of the border search exception—namely, interdicting

foreign contraband—and thus fall within its scope.

9 Cano emphasizes that the officials who arrested him were looking

for evidence of a crime, not contraband that could be seized at the border,

and this renders the search unconstitutional. He points to Officers Petonak

and Medrano, who searchedCano’s cell phone, and who testified that their

searches had a dual purpose: “to find some brief investigative leads in the

current case” and “to see if there[] [was] evidence of other things coming

across the border.” Because the agents acknowledged that they sought

evidence to use against Cano in building a criminal case, Cano argues that

the court should treat the search as one conducted for “general law

enforcement purposes” rather than a border search.

Cano’s focus on the officials’ subjective motivations is misplaced,

however. As the district court recognized, “courts have repeatedly held

that the Fourth Amendment’s reasonableness analysis is ‘predominantly

an objective inquiry.’” See Whren v. United States, 517 U.S. 806, 813

(1996) (upholding a “pretextual” stop because “[s]ubjective intentions

play no role in ordinary . . . Fourth Amendment analysis”). We have

upheld border searches of persons seeking entry even when those searches

were conducted “at the behest” of DEA agents seeking criminal evidence. 

See United States v. Schoor, 597 F.2d 1303, 1305–06 (9th Cir. 1979)

(holding a border search reasonable where it was conducted “at the

behest” of DEA agents and included a search for certain items of evidence

in addition to a search for contraband). Thus, the mere fact that Officers

Petonak and Medrano subjectively hoped to find “investigative leads”

pertaining to the seized shipment of cocaine does not render their searches

of Cano’s phone beyond the border search exception.
24 UNITED STATES V. CANO

This is a close question, but we think Cano has the better

of the argument. There is a difference between a search for

contraband and a search for evidence of border-related

crimes, although the distinction may not be apparent. 

Cotterman helps us focus on the difference. There, border

officials had been alerted that Cotterman had a criminal

record of sex abuse of minors and might be involved in “child

sex tourism.” Cotterman, 709 F.3d at 957. The officials

seized his laptop and subjected it to searches for child

pornography, which they found. In Cotterman, the child

pornography was contraband subject to seizure at the border. 

As contraband, the child pornography is also evidence of

various crimes, including possession of child pornography,

18 U.S.C. § 2252A(a)(5)(B), and importation of obscene

material, 18 U.S.C. § 1462(a). But nothing in Cotterman

authorized border officials to conduct a search for evidence

that Cotterman was involved in sex-related crimes generally. 

Border officials are authorized to seize “merchandise

which . . . shall have been introduced into the United States

in any manner contrary to law.” 19 U.S.C. § 482(a)

(emphasis added). The photos on Cotterman’s laptop

computer were such merchandise. 18 U.S.C. § 2252(a). But

border officials have no general authority to search for crime. 

This is true even if there is a possibility that such crimes may

be perpetrated at the border in the future. So, for example, if

U.S. officials reasonably suspect that a person who has

presented himself at the border may be engaged in price

fixing, see 15 U.S.C. § 1, they may not conduct a forensic

search of his phone or laptop. Evidence of price fixing—

texts or emails, for example—is not itself contraband whose

importation is prohibited by law. Such emails may be

evidence of a crime, but they are not contraband, and there is

no law prohibiting the importation of mere evidence of crime.
UNITED STATES V. CANO 25

We recognize that our analysis is in tension with the

Fourth Circuit’s decision in Kolsuz. Kolsuz was detained at

Washington Dulles International Airport when customs

agents discovered firearm parts in his luggage. Kolsuz, 890

F.3d at 138–39. Kolsuz was arrested and his cell phone

seized. Id. at 139. The agents subjected the phone to a

month-long forensic search, producing a 896-page report. Id. 

Kolsuz challenged the search, which the district court upheld

and the Fourth Circuit affirmed. Id. at 139–42. The court

approved the forensic search because the agents had “reason

to believe . . . that Kolsuz was attempting to export firearms

illegally” and that “their search would reveal not only

evidence of the export violation they already had detected,

but also ‘information related to other ongoing attempts to

export illegally various firearm parts.’” Id. at 143 (quoting

the district court; citation omitted). According to the Fourth

Circuit, “[t]he justification behind the border search

exception is broad enough to accommodate not only the

direct interception of contraband as it crosses the border, but

also the prevention and disruption of ongoing efforts to

export contraband illegally.” Id. (emphasis added).10

We agree with much of the Fourth Circuit’s discussion of

foundational principles, but we respectfully disagree with the

final step approving the search for further evidence that

10 As support for this proposition, the Fourth Circuit cited two district

court cases originating within our circuit. Both of those cases addressed

fact-patterns almost identical to Cano’s, and in each case the district court

held that the border-search exception was not limited to searching for

contraband directly. See United States v. Mendez, 240 F. Supp. 3d 1005,

1007–08 (D. Ariz. 2017); United States v. Ramos, 190 F. Supp. 3d 992,

999 (S.D. Cal. 2016). In neither case was the issue appealed to our circuit. 

Thus, Cano’s case presents the first opportunity for us to consider the

matter. 
26 UNITED STATES V. CANO

Kolsuz was smuggling weapons. Our disagreement focuses

precisely on the critical question that we previously

identified: Does the proper scope of a border search include

the power to search for evidence of contraband that is not

present at the border? Or, put differently, can border agents

conduct a warrantless search for evidence of past or future

border-related crimes? We think that the answer must be

“no.” The “[d]etection of . . . contraband is the strongest

historic rationale for the border-search exception.” MolinaIsidoro, 884 F.3d at 295 (Costa, J., specially concurring). 

Indeed, “every border-search case the Supreme Court has

decided involved searches to locate items being smuggled”

rather than evidence. Id. (emphasis added); see Montoya de

Hernandez, 473 U.S. at 537 (the border search is “to prevent

the introduction of contraband into this country”); United

States v. 12 200-Foot Reels of Super 8mm. Film, 413 U.S.

123, 125 (1973) (border searches are “necessary to prevent

smuggling and to prevent prohibited articles from entry”);

United States v. Thirty-Seven Photographs, 402 U.S. 363, 376

(1971) (“Customs officers characteristically inspect luggage

and their power to do so is not questioned in this case; it is an

old practice and is intimately associated with excluding

illegal articles from the country”). In fact, the Court has long

“draw[n] a sharp distinction between searches for contraband

and those for evidence that may reveal the importation of

contraband.” Molina-Isidoro, 884 F.3d at 296 (Costa, J.,

specially concurring). The classic statement on the

distinction between seizing goods at the border because their

importation is prohibited and seizing goods at the border

because they may be useful in prosecuting crimes is found in

Boyd v. United States:

Is a search and seizure, or, what is equivalent

thereto, a compulsory production of a man’s
UNITED STATES V. CANO 27

private papers, to be used in evidence against

him in a proceeding to forfeit his property for

alleged fraud against the revenue laws—is

such a proceeding for such a purpose an

“unreasonable search and seizure” within the

meaning of the fourth amendment of the

constitution? . . . . The search for and seizure

of stolen or forfeited goods, or goods liable to

duties and concealed to avoid the payment

thereof, are totally different things from a

search for and seizure of a man’s private

books and papers for the purpose of obtaining

information therein contained, or of using

them as evidence against him. The two things

differ toto coelo. 

116 U.S. 616, 622–23 (1886), overruled in part on other

grounds by Warden, Md. Penitentiary v. Hayden, 387 U.S.

294 (1967); see also id. at 633 (stating that compelling a man

to produce the evidence against himself not only violates the

Fifth Amendment, but makes the seizure of his “books and

papers” unreasonable under the Fourth Amendment).

Although we continue to acknowledge that “[t]he

Government’s interest in preventing the entry of unwanted

persons and effects is at its zenith at the international border”

and that “the expectation of privacy is less at the border than

it is in the interior,” Flores-Montano, 541 U.S. at 152, 154,

we hold that the border search exception authorizes

warrantless searches of a cell phone only to determine

whether the phone contains contraband. A broader search

cannot be “justified by the particular purposes served by the

exception.” Florida v. Royer, 460 U.S. 491, 500 (1983). 
28 UNITED STATES V. CANO

2. The Impact of a Limited Scope for Border Searches

Our conclusion that the border search exception is

restricted in scope to searches for contraband implicates two

practical limitations on warrantless border searches. First,

border officials are limited to searching for contraband only;

they may not search in a manner untethered to the search for

contraband. The Supreme Court has repeatedly emphasized

that “[t]he scope of the search must be ‘strictly tied to and

justified by’ the circumstances which rendered its initiation

permissible.” Terry v. Ohio, 392 U.S. 1, 19 (1968).

The validity of the manual searches conducted by Agents

Petonak and Medrano at their inception is beyond dispute. 

Manual searches of a cell phone at the border can be

conducted without any suspicion whatsoever, see Cotterman,

709 F.3d at 960, and both agents were officers of HSI and

thus had authority to conduct border searches, Soto-Soto, 598

F.2d at 548–49. As the Supreme Court explained in Terry,

however, “a search which is reasonable at its inception may

violate the Fourth Amendment by virtue of its intolerable

intensity and scope.” 392 U.S. at 18.

Once Cano was arrested, Agent Petonak briefly searched

Cano’s phone and observed that there were no text messages. 

The observation that the phone contained no text messages

falls comfortably within the scope of a search for digital

contraband. Child pornography may be sent via text

message, so the officers acted within the scope of a

permissible border search in accessing the phone’s text

messages.

Agent Medrano conducted a second manual search of the

phone log and text messages on Cano’s phone. Medrano,
UNITED STATES V. CANO 29

however, did more than thumb through the phone consistent

with a search for contraband. He also recorded phone

numbers found in the call log, and he photographed two

messages received after Cano had reached the border. Those

actions have no connection whatsoever to digital contraband. 

Criminals may hide contraband in unexpected places, so it

was reasonable for the two HSI officers to open the phone’s

call log to verify that the log contained a list of phone

numbers and not surreptitious images or videos. But the

border search exception does not justify Agent Medrano’s

recording of the phone numbers and text messages for further

processing, because that action has no connection to ensuring

that the phone lacks digital contraband. Accordingly, to the

extent that Agent Medrano’s search of Cano’s phone went

beyond a verification that the phone lacked digital

contraband, the search exceeded the proper scope of a border

search and was unreasonable as a border search under the

Fourth Amendment.11

11 The fact of Cano’s arrest does not affect our analysis. The border

search does not lose its identity as such once Cano was arrested. The

United States retains a strong interest in preventing contraband from

entering the United States, whether it is brought in inadvertently,

smuggled, or admitted into the United States once its owner is arrested. 

See United States v. Ickes, 393 F.3d 501, 503–05 (4th Cir. 2005)

(upholding the post-arrest search of a laptop computer at the border where

the officials had reason to suspect the computer carried child

pornography); see also United States v. Bates, 526 F.2d 966, 967–68 (5th

Cir. 1976) (per curiam) (upholding a search of the defendant’s vehicle

after he had been arrested at the border for violating his bond in

connection with a previous drug crime under both the search incident to

arrest and the border search exception).

The government has not argued that the forensic search of Cano’s

phone can be justified as a search incident to lawful arrest. Such an

argument is foreclosed by Riley. See Riley, 573 U.S. at 388–91. Nor has
30 UNITED STATES V. CANO

Second, because the border search exception is limited in

scope to searches for contraband, border officials may

conduct a forensic cell phone search only when they

reasonably suspect that the cell phone contains contraband. 

We have held that a “highly intrusive” search—such as a

forensic cell phone search—requires some level of

particularized suspicion. Cotterman, 709 F.3d at 963, 968;

see Flores-Montano, 541 U.S. at 152. But that just begs the

question: Particularized suspicion of what? Contraband? Or

evidence of future border-related crimes? Having concluded

above that border searches are limited in scope to searches for

contraband and do not encompass searches for evidence of

past or future border-related crimes, we think the answer here

is clear: to conduct a more intrusive, forensic cell phone

search border officials must reasonably suspect that the cell

phone to be searched itself contains contraband. 

Were we to rule otherwise, the government could conduct

a full forensic search of every electronic device of anyone

arrested at the border, for the probable cause required to

justify an arrest at the border will always satisfy the lesser

reasonable suspicion standard needed to justify a forensic

search. As the Court pointed out in Riley, modern cell phones

are “minicomputers” with “immense storage capacity.” 573

U.S. at 393. Such phones “carry a cache of sensitive personal

information”—“[t]he sum of an individual’s private life”—

such that a search of a cell phone may give the government

the government argued that once Medrano saw the phone numbers in the

call log and the text messages that he could record them consistent with

the plain view exception. See United States v. Comprehensive Drug

Testing, 621 F.3d 1162, 1175–77 (9th Cir. 2010) (en banc) (per curiam),

overruled in part on other grounds as recognized by Demaree v.

Pederson, 887 F.3d 870, 876 (9th Cir. 2018) (per curiam). 
UNITED STATES V. CANO 31

not only “sensitive records previously found in the home,”

but a “broad array of private information never found in a

home in any form—unless the phone is.” Id. at 393–97. 

Were we to give the government unfettered access to cell

phones, we would enable the government to evade the

protections laid out in Riley “on the mere basis that [the

searches] occurred at the border.” Soto-Soto, 598 F.2d at 549. 

Moreover, in cases such as this, where the individual

suspected of committing the border-related crime has already

been arrested, there is no reason why border officials cannot

obtain a warrant before conducting their forensic search. This

“is particularly true in light of ‘advances’ in technology that

now permit ‘the more expeditious processing of warrant

applications.’” Birchfield v. North Dakota, 136 S. Ct. 2160,

2192 (2016) (quoting Missouri v. McNeely, 569 U.S. 141, 154

(2013)); see Riley, 573 U.S. at 401. Indeed, in most cases the

time required to obtain a warrant would seem trivial

compared to the hours, days, and weeks needed to complete

a forensic electronic search. See, e.g., Wanjiku, 919 F.3d at

477 (noting that a forensic “preview” takes one to three

hours; the full examination “could takemonths”); Kolsuz, 890

F.3d at 139 (describing how the forensic search “lasted for a

full month, and yielded an 896-page report”); Cotterman, 709

F.3d at 959 (describing how the first forensic search was

conducted over five days; additional evidence was found

“[o]ver the next few months”). We therefore conclude that

border officials may conduct a forensic cell phone search

only when they reasonably suspect that the cell phone to be

searched itself contains contraband.

Applied here, if the Cellebrite search of Cano’s cell phone

qualifies as a forensic search, the entire search was
32 UNITED STATES V. CANO

unreasonable under the Fourth Amendment.12 Although

Agents Petonak and Medrano had reason to suspect that

Cano’s phone would contain evidence leading to additional

drugs, the record does not give rise to any objectively

reasonable suspicion that the digital data in the phone

contained contraband.13 Absent reasonable suspicion, the

border search exception did not authorize the agents to

conduct a warrantless forensic search of Cano’s phone, and

evidence obtained through a forensic search should be

suppressed. 

C. Good Faith Exception

We next consider whether the evidence uncovered by the

searches is nevertheless allowed by the good faith exception. 

Having held that the manual searches partially violated the

Fourth Amendment and having held that, if the Cellebrite

12 Whether the Cellebrite search constitutes a forensic search is

disputed. Because the district court passed on the issue without deciding

it, because neither party has briefed the question to us, and because we are

vacating Defendant’s conviction, we decline to reach the merits of the

parties’ dispute. See ASSE Int’l, Inc. v. Kerry, 803 F.3d 1059, 1079 (9th

Cir. 2015).

13 Indeed, the detection-of-contraband justificationwould rarely seem

to apply to an electronic search of a cell phone outside the context of child

pornography. The courts of appeals have just begun to confront the

difficult questions attending cell phone searches at the border. Most ofthe

cases have involved child pornography. See, e.g., Wanjiku, 919 F.3d 472;

Touset, 890 F.3d 1227; Molina-Isidoro, 884 F.3d 287; Vergara, 884 F.3d

1309; Cotterman, 709 F.3d 952. Among the courts of appeals, only the

Fourth Circuit has addressed the question outside the context of

pornography. Kolsuz, 890 F.3d 133 (exportation of firearms parts); see

also United States v. Kim, 103 F. Supp. 3d 32 (D.D.C. 2015) (exports in

violation of Iranian trade embargo); United States v. Saboonchi, 990 F.

Supp. 2d 536 (D. Md. 2014) (same).
UNITED STATES V. CANO 33

search of Cano’s phone was a forensic search, it violated the

Fourth Amendment, we must determine whether the

appropriate remedy is suppression of the evidence. The

exclusionary rule is “a ‘prudential’ doctrine”; it is “‘not a

personal constitutional right,’ nor is it designed to ‘redress the

injury’ occasioned by an unconstitutional search.” Davis v.

United States, 564 U.S. 229, 236 (2011) (quoting Stone v.

Powell, 428 U.S. 465, 486 (1976)). Because “[e]xclusion

exacts a heavy toll on both the judicial system and society at

large,” we invoke the rule when we are confident that it will

“deter future Fourth Amendment violations.” Id. at 236–37. 

The exclusionary rule does not deter such violations “when

the police conduct a search in objectively reasonable reliance

on binding judicial precedent.” Id. at 239. We have said that

the good faith exception applies only to searches where

“binding appellate precedent . . . ‘specifically authorizes’ the

police’s search.” United States v. Lara, 815 F.3d 605, 613

(9th Cir. 2016) (quoting Davis, 564 U.S. at 232). It is not

sufficient for the question to be “unclear” or for the

government’s position to be “plausibly . . . permissible.” Id.

at 613–14. At the same time, the “precedent [does not have]

to constitute a factual match with the circumstances of the

search in question for the good-faith exception to apply” so

as not to “make the good-faith exception a nullity.” United

States v. Lustig, 830 F.3d 1075, 1082 (9th Cir. 2016).

The government points to Cotterman as support for the

good faith of the officials. We fail to see how border officials

could believe that Cotterman was “binding appellate

precedent” authorizing their search. Although we have

concluded that Cotterman is still good law after Riley, the

officials could not rely on Cotterman to justify a search for

evidence; Cotterman was a search for contraband that the

government has a right to seize at the border. Here, the
34 UNITED STATES V. CANO

officials’ search was objectively tied only to proving their

case against Cano and finding evidence of future crimes. 

Searching for evidence and searching for contraband are not

the same thing. 

We understand that border officials might have thought

that their actions were reasonable, and we recognize that

border officials have to make in-the-moment decisions about

how to conduct their business—whether or not they have

written guidance from the courts. But as we understand the

Davis rule, the good faith exception to the exclusionary rule

applies only when the officials have relied on “binding

appellate precedent.” See Lara, 815 F.3d at 613; see also

Wanjiku, 919 F.3d at 485–86 (finding that agents had

reasonable suspicion to search the defendant’s cell phone,

laptop, and portable hard drive for child pornography;

holding that, if probable cause was required, the officials

acted in good faith). This is a rapidly developing area, not an

area of settled law. Even if our decision in Cotterman

rendered the searches “plausibly . . . permissible,” it did not

“specifically authorize” the cell phone searches at issue here. 

Lara, 815 F.3d at 613–14. 

* * *

In sum, the manual searches and the Cellebrite search of

Cano’s cell phone exceeded the scope of a valid border

search. Because the good faith exception does not apply,

most of the evidence obtained from the searches of Cano’s

cell phone should have been suppressed. We thus reverse the

district court’s order denying Cano’s motion to suppress, and

we vacate Cano’s conviction. On any retrial, the district court

should determine whether any additional evidence from the

warrantless searches of Cano’s cell phone should be
UNITED STATES V. CANO 35

suppressed, either because the Cellebrite search qualifies as

a forensic search, which the government lacked reasonable

suspicion to conduct, or because the evidence exceeds the

proper scope of a border search.

III. DISCOVERY ISSUES

Cano has also alleged that the government violated his

rights under both Brady and Federal Rule of Criminal

Procedure 16 when it failed to turn over certain information

that Cano requested from the FBI and DEA. We address

Cano’s discovery claims, as the issues may be relevant on any

retrial. 

Under Brady, the prosecution has an obligation, imposed

by the Due Process Clause, to produce “evidence favorable to

an accused upon request . . . where the evidence is material

either to guilt or to punishment.” 373 U.S. at 87. 

“[E]vidence is material only if there is a reasonable

probability that, had the evidence been disclosed to the

defense, the result of the proceeding would have been

different.” United States v. Bagley, 473 U.S. 667, 682

(1985).14 

Under Rule 16, the government must, upon request, turn

over any documents “within the government’s possession,

custody, or control” that are “material to preparing the

defense.” Fed. R. Crim. P. 16(a)(1)(E)(i). The defendant

“must make a threshold showing of materiality, which

requires a presentation of facts which would tend to show that

the Government is in possession of information helpful to the

14 We review de novo whether a Brady violation has occurred. 

United States v. Stever, 603 F.3d 747, 752 (9th Cir. 2010).
36 UNITED STATES V. CANO

defense.” United States v. Muniz-Jaquez, 718 F.3d 1180,

1183–84 (9th Cir. 2013) (quoting United States v. Stever, 603

F.3d 747, 752 (9th Cir. 2010)). Because “[i]nformation that

is not exculpatory or impeaching may still be relevant to

developing a possible defense,” Rule 16 is “broader than

Brady.” Id. at 1183.15

Under both Brady and Rule 16, the government “has no

obligation to produce information which it does not possess

or of which it is unaware.” Sanchez v. United States, 50 F.3d

1448, 1453 (9th Cir. 1995). It has an obligation to turn over

onlymaterial, exculpatoryor otherwise helpful to the defense,

that it has in its possession.

16

“Possession” is not limited to

what the prosecutor personally knows. Browning v. Baker,

875 F.3d 444, 460 (9th Cir. 2017), cert. denied, 138 S. Ct.

2608 (2018); United States v. Bryan, 868 F.2d 1032, 1036

(9th Cir. 1989). Because prosecutors are in a “unique

position to obtain information known to other agents of the

government,” they have an obligation to “disclos[e] what

[they] do[] not know but could have learned.” Carriger v.

Stewart, 132 F.3d 463, 480 (9th Cir. 1997) (en banc); see also

Kyles v. Whitley, 514 U.S. 419, 437 (1995) (describing how

15 Although discovery rulings are generally reviewed for abuse of

discretion, Stever, 603 F.3d at 752, we review a district court’s

interpretation of the discovery rules de novo, United States v. CedanoArellano, 332 F.3d 568, 570–71 (9th Cir. 2003). 

16 The “possession” element of Brady is treated as coextensive with

that of Rule 16. See, e.g., United States v. Bryan, 868 F.2d 1032, 1037

(9th Cir. 1989) (using the same “knowledge and access” test to determine

“possession” for both Rule 16 and Brady); United States v. Grace, 401 F.

Supp. 2d 1069, 1076 (D. Mont. 2005) (“Whether exculpatory information

is in the government’s possession for Brady purposes is measured by the

same . . . test used under Rule 16(a)(1)(E) for discovery.”).
UNITED STATES V. CANO 37

the “individual prosecutor has a duty to learn of any favorable

evidence known to [those] acting on the government’s

behalf”); Youngblood v. West Virginia, 547 U.S. 867, 869–70

(2006) (per curiam). This includes information held by

subordinates such as investigating police officers, see Kyles,

514 U.S. at 438; United States v. Price, 566 F.3d 900, 908–09

(9th Cir. 2009), and sometimes extends to information held

by other executive branch agencies, see United States v.

Santiago, 46 F.3d 885, 893 (9th Cir. 1995); United States v.

Jennings, 960 F.2d 1488, 1490–91 (9th Cir. 1992).

Documents held by another executive branch agency are

deemed to be “in the possession of the government” if the

prosecutor has “knowledge of and access to” the documents. 

Bryan, 868 F.2d at 1036. Knowledge and access are

presumed if the agency participates in the investigation of the

defendant. Id. (“The prosecutor will be deemed to have

knowledge of and access to anything in the possession,

custody or control of any federal agency participating in the

same investigation of the defendant.”). However, “a federal

prosecutor need not comb the files of every federal agency

which might have documents regarding the defendant in order

to fulfill his or her obligations under [Rule 16].” Id.; see also

Kyles, 514 U.S. at 437 (“We have never held that the

Constitution demands an open file policy . . . .”).

Here, Cano asserted a third-party defense theory: he was

staying in Tijuana with his cousin, Jose Medina; Medina was

a member of the Latin Kings gang which was involved in the

drug trade; and Medina had access to Cano’s car before Cano

was stopped at the border. Cano requested that the U.S.

Attorney’s Office turn over any material held by HSI, the

FBI, and the DEA relating to: (1) records linking his cousin

Jose Medina to drug sales, distribution, and trafficking; and
38 UNITED STATES V. CANO

(2) documentation showing a link between the Latin Kings

and drug trafficking through the United States-Mexico

border. The district court found that both requests might

produce evidence that was exculpatory under Brady and

material under Rule 16, but limited Cano’s discovery to only

material held by HSI. The court concluded that the

prosecutor did not have access to evidence held by the FBI

and DEA, and thus had no obligation to provide such

evidence, because both agencies had “rebuffed” the

prosecutor’s attempts to obtain information. Thus, the only

issue raised on appeal is whether any material held by the

DEA and FBI should be deemed “within the government’s

possession.” 

We find no evidence that the prosecution had knowledge

or possession of evidence showing that Medina or the Latin

Kings were involved in drug trafficking at the MexicoCalifornia border. Medina had one drug-related conviction,

and it was for simple possession of cocaine, not trafficking. 

Before trial, however, the prosecution team reached out to

Medina and promised him immunity and immigration

documents in exchange for cooperation and information

concerning drug importation. Although Medina originally

rebuffed the government, he eventually offered to work with

the government and “stated that he would be able to assist the

Government with the . . . biggest RICO . . . case and drug

seizures of 20 to 25 kilograms at a time.” The district court

found that Medina’s statements “spawn[ed] an inference that

[he] is closely connected to the drug-traffickers in Tijuana.” 

Based on this inference, Cano argues that the government had

sufficient knowledge of a possible connection between

Medina and drug trafficking to trigger the government’s

discovery obligations.
UNITED STATES V. CANO 39

Cano’s argument, however, misstates the test we first set

out in Bryan. Cano has argued only that the prosecutor had

knowledge that certain facts might exist. However, we have

said that the prosecutor’s disclosure obligations turn on “the

extent to which the prosecutor has knowledge of and access

to the documents sought by the defendant.” Bryan, 868 F.2d

at 1036 (emphasis added); see also Santiago, 46 F.3d at 894

(analyzing whether the prosecutor had knowledge of and

access to certain inmate files). We have required disclosure

only of documents that the prosecutor knew existed. Bryan,

868 F.2d at 1034–37. 

Here, although Cano has presented evidence alleging a

plausible connection between Medina and drug trafficking,

Cano has failed to adduce any evidence showing that

prosecutors or investigators knew that the FBI or the DEA

possessed documents showing that connection. In fact, the

record established the opposite. One of the HSI agents ran

Medina’s name through two different law enforcement

clearinghouses—in which the FBI and DEA both

participate—and neither search returned any hits.

Moreover, the prosecutor did not have access to FBI or

DEA files and thus was under no obligation to “comb the

files” of the FBI and DEA for documents relating to

Medina.17 We have occasionally presumed that a prosecutor

17 Cano sought to introduce a 2015 report from the FBI’s National

Gang Intelligence Center listing the Latin Kings as one of the top gangs

involved in cross border crime, and including drug importation in its list

of cross-border crimes. (The evidence was not ultimately presented at

trial.) Cano also proffered information concerning two government

informants working within the Latin Kings. Although these reports may

suggest that the FBI may have had further information regarding a

connection between the Latin Kings and drug importation, Cano has not
40 UNITED STATES V. CANO

has access to an agency’s files where the prosecutor actually

obtained inculpatory information from the agency, even if the

agency was not involved in the investigation or prosecution. 

See Santiago, 46 F.3d at 894 (concluding that the prosecutor

had access to other inmates’ prison files where the prosecutor

was able to obtain the defendant’s prison file from the Bureau

of Prisons). Here, however, the U.S. Attorney’s Office

advised the district court that it did not obtain any evidence—

inculpatory or exculpatory—from the FBI or the DEA. 

Following the district court’s initial discovery order, HSI’s

agent—Agent Petonak—made a formal request to the legal

counsel for the FBI and the DEA for any “materials related to

the Latin Kings importing cocaine from Mexico to the United

States,” but both agencies “declined to provide [him] with

any such information.” Neither agency revealed whether any

such information existed or provided a reason for its refusal. 

The U.S. Attorney’s Office also reached out to the FBI and

the DEA for Latin Kings-related discovery. That request was

also denied. 

Cano argues that the FBI and DEA’s refusal to turn over

information in this particular case should not be

determinative and that the test for access under Bryan and

Santiago requires only that the U.S. Attorney’s Office or

investigating agency generally have access to this type of

information. Cano points to evidence from both prosecution

and defense witnesses that HSI regularly works with the FBI

and the DEA; that “interagency cooperation has been

emphasized” after September 11, 2001; that agents from the

different agencies regularly access information for one

another; that a DEA representative worked in Agent

Petonak’s office; and that agents are often cross-listed

established that the prosecutor had access to the FBI’s or the DEA’s files. 
UNITED STATES V. CANO 41

between agencies. From this, Cano argues that HSI generally

has access to FBI and DEA files for inculpatory purposes,

and thus asserts that the refusal of the FBI and DEA to

provide information in this particular case should not relieve

HSI of its discovery obligations. To rule otherwise, Cano

contends, would allow these withholding agencies “to

effectively wall off exculpatory information from the

government in a particular defendant’s case, all the while

providing the government free-flowing access to information

in its overall investigations.”

Although we are sympathetic to Cano’s concerns

regarding strategic withholding, the rule Cano urges us to

adopt is much too broad. Brady and Rule 16 obligations are

case specific. In Bryan we stated that the test for

“possession” turns on the prosecutor’s “knowledge of and

access to the documents sought by the defendant in each

case” and that “[t]he prosecutor will be deemed to have

knowledge of and access to anything in the possession,

custody or control of any federal agency participating in the

same investigation of the defendant.” 868 F.2d at 1036

(emphases added). Such a case-by-case approach makes

sense, as the FBI and DEA may have valid concerns over

revealing sensitive information in cases wholly unrelated to

the agencies’ own workload; the agencies may be reluctant to

cooperate in a particular investigation if it means opening

their files in other investigations. If Cano thinks that the FBI

or the DEA have other information, not known to the U.S.

Attorney’s Office or the investigating officers, he may file a

request under the Freedom of Information Act, subject to that

Act’s own restrictions on releasing “records or information

compiled for law enforcement purposes.” 5 U.S.C.

§ 552(b)(7). Brady and Rule 16 are not a means for a

defendant to require the prosecutor to do this work for him. 
42 UNITED STATES V. CANO

See generally Roth v. U.S. Dep’t of Justice, 642 F.3d 1161,

1175–76 (D.C. Cir. 2011); Boyd v. Crim. Div. of U.S. Dep’t

of Justice, 475 F.3d 381, 386–89 (D.C. Cir. 2007). 

Cano is unable to identify any case in which the

prosecutor was required to obtain discovery from an agency

wholly unrelated to the investigation of the defendant in spite

of that agency’s refusal to comply; all of the cases cited by

Cano imposing a “duty to learn” on the prosecutor involve

independent federal agencies that had participated in the

investigation of the defendant. See Price, 566 F.3d at

908–09; Carriger, 132 F.3d at 479–80; United States v.

Perdomo, 929 F.2d 967, 971 (3d Cir. 1991); United States v.

Osorio, 929 F.2d 753, 762 (1st Cir. 1991). Indeed, the Third

Circuit has held that a Brady obligation is not triggered where

the agency did not participate in the investigation in any way,

did not share any information with the prosecuting team, and

where the prosecutor had no authority or control over the

agency’s members. United States v. Pelullo, 399 F.3d 197,

218 (3d Cir. 2005); see also United States v. Salyer, 271

F.R.D. 148, 156 (E.D. Cal. 2010) (concluding that “[t]he need

for formal process in the acquisition of documents [from

another agency] is the antithesis of ‘access’”). We similarly

now hold that the prosecutor should not be held to have

“access” to any information that an agency not involved in

the investigation or prosecution of the case refuses to turn

over. 

Because the HSI agents and prosecutors in Cano’s case

neither knew of nor had access to any additional files relating

to Medina and the Latin Kings, we conclude that the

government has satisfied its discovery obligations under

Brady and Rule 16. 
UNITED STATES V. CANO 43

IV. CONCLUSION

We REVERSE the district court’s order denying Cano’s

motion to suppress and VACATE Cano’s conviction.