NOT PRECEDENTIAL

UNITED STATES COURT OF APPEALS

FOR THE THIRD CIRCUIT

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No. 16-3365

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UNITED STATES OF AMERICA

v.

JAVIER PEREZ,

Appellant

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On Appeal from the United States District Court

for the Eastern District of Pennsylvania

(D.C. No. 2-14-cr-00611-001)

District Judge: Honorable Jan E. DuBois

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Argued May 10, 2017

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Before: AMBRO, RESTREPO, and COWEN, Circuit Judges.

(Filed: October 18, 2017)

Keith M. Donoghue, Esquire (Argued)

Brett G. Sweitzer

Leigh M. Skipper

Federal Community Defender Office 

For the Eastern District of Pennsylvania

Suite 540 West – Curtis Center

601 Walnut Street

Philadelphia, PA 19106

Counsel for Appellant
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Louis D. Lappen, Esquire

Robert A. Zauzmer

Albert S. Glenn (Argued)

Office of the United States Attorney

615 Chestnut Street, Suite 1250

Philadelphia, PA 19106

Counsel for Appellee

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OPINION*

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RESTREPO, Circuit Judge.

Javier Perez appeals from his conviction of possession of child pornography, 

arguing that the initial motion to suppress evidence recovered in a general search of his 

computer was denied in error, and that the Government’s presentation of child 

pornography evidence at trial—although Perez offered to stipulate to every element 

except identity—unduly prejudiced the jury. For the reasons that follow, we will affirm.

I

Because we write for the benefit of the parties, we set out only the facts necessary 

for the discussion that follows. In October 2013, an FBI agent discovered a user of a 

common peer-to-peer file-sharing network sharing a video of child pornography. The 

FBI subsequently subpoenaed the user’s internet service provider for the account 

information corresponding to the internet protocol (“IP”) address in question, and 

discovered that the account belonged to Perez, located at a residence in Philadelphia. 

 

* This disposition is not an opinion of the full Court and, pursuant to I.O.P. 5.7, 

does not constitute binding precedent.
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Using the child pornography that the agent had discovered being shared by a user at that 

IP address, the FBI obtained a warrant authorizing a search and seizure of all computer 

equipment at that physical address. 

In executing the warrant, the FBI discovered that five people lived in the 

residence, including an individual who repaired computers out of the home. Among the 

five residents and the computer repair business, the home contained 130 computers and 

digital storage items, all of which the FBI seized. The only items ultimately found to 

contain child pornography came from the basement in which Perez resided. 

To guide the subsequent human-conducted search of the desktop computer

recovered from Perez’s basement space, a forensic team duplicated the computer’s hard 

drive, then ran software that scanned the entire drive and catalogued all of its contents by 

file type. The scan checked for mismatches of file extensions and file contents—e.g., 

assessing whether an image file had been saved in a .doc format to obscure its true 

content—and also checked images against databases of known child pornography. 

Agents used the results of the forensic scan to guide a human search of web browsing 

history, email, photos and videos, and files specifically identified as pertaining to missing 

and exploited children. The human search involved some limits; with respect to emails, 

for example, agents looked at metadata first and subsequently looked at message content 

if the metadata prompted additional questions. With respect to pictures and videos, 

agents looked at thumbnails first and then viewed expanded versions if the thumbnail 

seemed to involve responsive material. The human search, however, included an 
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inspection of the entire web history, including browsing, search queries, bookmarks, and 

social media usage. 

Having discovered a number of images and videos of child pornography, as well 

as internet browsing and search history that indicated the user of the computer had sought 

out such images, the Government charged Perez with numerous offenses. In advance of 

trial, he indicated that he planned to dispute only the identity of the person who had 

engaged in the conduct at issue—noting that, because the basement did not even have a 

door, anyone could have accessed the computer—and offered to stipulate to all nonidentity elements of the crimes, including that the media files were sexually explicit and 

contained minor children. The Government declined the stipulation, and presented child 

pornography to the jury after the District Court overruled Perez’s objections on the basis 

of undue prejudice. The jury ultimately convicted Perez of possession, but not 

distribution. 

II1

The Fourth Amendment prohibits “[g]eneral warrants” that would allow 

“exploratory rummaging in a person’s belongings.” Andresen v. Maryland, 427 U.S. 

463, 479 (1976) (quoting Coolidge v. New Hampshire, 403 U.S. 443, 467 (1971)). To 

guard against such general warrants, courts require “particularity,” which “prevents the 

seizure of one thing under a warrant describing another.” Marron v. United States, 275 

U.S. 192, 196 (1927). Particularity has three components: “First, a warrant must identify 

 

1 We have jurisdiction under 28 U.S.C. § 1291.
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the specific offense for which the police have established probable cause. Second, a 

warrant must describe the place to be searched. Third, the warrant must specify the items 

to be seized by their relation to designated crimes.” United States v. Galpin, 720 F.3d 

436, 445-46 (2d Cir. 2013) (citations omitted). Ultimately, the particularity requirement 

intends that “nothing is left to the discretion of the officer executing the warrant.” 

Marron, 192 U.S. at 196.

Courts—including our own—have struggled to adapt Fourth Amendment search 

doctrines designed for physical spaces to digital contexts. Riley v. California, 134 S.Ct. 

2473, 2493 (2014). Adapting the particularity requirement to searches of digitally stored 

information presents one example of that problem. For one thing, the place to be 

searched encompasses much more information in a search of digital storage than in one 

of physical space, which appears to allow the plain view exception to undercut the 

warrant requirement. Putting all information on a digital storage device that can hold 

data “roughly equal to 16 billion thick books,” United States v. Ganias, 824 F.3d 199, 

218 (2d Cir. 2016), in plain view whenever law enforcement officers have a valid warrant 

to search for something that may exist in the storage substantially expands the aggregate 

quantity of material encompassed by the exception. Conversely, because of individuals’ 

ability to “hide, mislabel, or manipulate files,” United States v. Stabile, 633 F.3d 219, 237 

(3d Cir. 2011), “there may be no practical substitute for actually looking in many 

(perhaps all)” files and locations during a search of digital storage. Id. at 239.

To the extent that some courts have tried to address this tension, results have been 

mixed. In 2009, the Ninth Circuit issued an en banc opinion with five principles to guide 
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Magistrate Judges in issuing or approving warrants for digital storage spaces. United 

States v. Comprehensive Drug Testing, Inc., 579 F.3d 989 (9th Cir. 2009) (en banc) 

(“CDT II”). Notably, the Ninth Circuit reissued the opinion about a year later as a per 

curiam opinion, which differed little except that it moved the guidance protocols to a 

(non-binding) concurrence. United States v. Comprehensive Drug Testing, Inc., 621 F.3d 

1162 (9th Cir. 2010) (en banc) (per curiam) (“CDT III”); id. at 1179-80 (Kozinski, C.J., 

concurring). As a result, subsequent Ninth Circuit panels have upheld broad warrants 

authorizing searches of all of a target’s digital storage devices and media despite the 

“absence of precautionary search protocols.” United States v. Schesso, 730 F.3d 1040, 

1043 (9th Cir. 2013). 

Rejecting an attempt to jettison the plain view exception in the digital storage 

context, the Seventh Circuit “simply counsel[s] officers and others involved in searches 

of digital media to exercise caution to ensure that warrants describe with particularity the 

things to be seized and that searches are narrowly tailored to uncover only those things 

described.” United States v. Mann, 592 F.3d 779, 786 (7th Cir. 2010). The Sixth Circuit 

has described computer searches as a “unique problem,” but it has declined to impose “a 

specific search protocol,” instead applying “the Fourth Amendment’s bedrock principle 

of reasonableness on a case-by-case basis.” United States v. Richards, 659 F.3d 527, 538 

(6th Cir. 2011). The Tenth Circuit has suppressed incriminating digital evidence of child 

pornography discovered by an agent searching a computer for evidence of drug sales,

declining to apply the plain view exception to the contents of digital files (as opposed to 

the files themselves). United States v. Carey, 172 F.3d 1268, 1273 (10th Cir. 1999).
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Two years later, however, the same Court declined to suppress child pornography

discovered by an agent who “proceeded to rummage through the hard drive for more 

images of child pornography despite the fact that he did not possess a warrant to conduct 

such a search,” because it was “persuaded the search was reasonable.” United States v. 

Walser, 275 F.3d 981, 987 (10th Cir. 2001).

Factual circumstances often complicate the problem. Often, as here, the initial 

search is undertaken by a computer program rather than a human. Searches of digitally

stored data often implicate the rights of other individuals not included in the warrant—

which happens more often and to more people with the increased prevalence of cloud 

storage. Leaving aside the intermingling of responsive and non-responsive data of a 

named individual, cloud storage often intermingles the data of an individual named in the 

warrant with the data of an individual not even under suspicion. See CDT III, 621 F.3d at 

1166; see also Richards, 629 F.3d at 552 (6th Cir. 2011) (Nelson Moore, J., concurring in 

the judgment); see also Schesso, 730 F.3d at 1049.

Federal courts have yet to strike a tenable doctrinal balance between protecting the 

constitutional rights of criminal suspects whose digital storage law enforcement agents 

intend to investigate and the practical challenges facing those same agents seeking 

specific information in the proverbial digital haystack. Neither has Congress struck a 

statutory balance nor the Executive branch via regulation. We do not attempt to do so

today.

* * *
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We “review[] the District Court’s denial of a motion to suppress for clear error as 

to the underlying factual findings and exercise[] plenary review of the District Court’s 

application of the law to those facts.” United States v. Perez, 280 F.3d 318, 336 (3d Cir. 

2002). In the absence of statutes and doctrine that better address rapidly evolving 

technology, the manner of searching digital storage is circumscribed by objective 

reasonableness rather than specific search protocols. Stabile, 633 F.3d at 239. 

Here, Perez did not argue that the law enforcement agents exceeded the scope of 

the warrant, nor could he have. Unlike cases of agents exceeding the scope of a warrant 

authorizing a search for evidence of one type of criminal activity by rummaging for 

evidence of other types of activities, the warrant here specifically described the target of 

the search. Perez did not argue even that the initial computer scan—by which law 

enforcement agents preliminarily scanned the entire contents of the hard drive—was 

unreasonable. Instead, he merely argued overbreadth as to the execution of the warrant, 

and would have preferred that the agents searched the digital storage in a particular order. 

As the agents stayed within the scope of the warrant and employed a search protocol 

guided by an initial scan whose propriety Perez does not dispute, the District Court did 

not err in denying the motion to suppress.

III

Perez, as noted, also disputes the District Court’s decision to allow the 

Government to present graphic evidence of child pornography to the jury. We review a 

District Court’s determination after engaging in a Rule 403 balancing for abuse of 

discretion. United States v. Sampson, 980 F.2d 883, 886 (3d Cir. 1992). Perez argues
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that, because he disputed only identity, the Government’s refusal to accept his stipulation 

and presentation of child pornography amounted to undue prejudice. Recent precedent 

forecloses this line of argument. “The government is entitled to prove its case free from a 

defendant’s preference to stipulate the evidence away.” United States v. Finley, 726 F.3d 

483, 492 (3d Cir. 2013). Finley arose in the same factual circumstances as here—a 

defendant in a child pornography case offered to stipulate to all elements except 

identity—and is binding on subsequent panels. Perez himself recognizes this, allowing

that “precedent of this Court is presently to the contrary,” Appellant’s Br. at 18, and 

merely asks to preserve the issue for certiorari or collateral review. Perez may consider 

the issue preserved, and we affirm the District Court.

IV

For the foregoing reasons, we will affirm the District Court’s denial of Perez’s 

motion to suppress and its decision to allow the Government to present evidence of child 

pornography at trial.