NOT PRECEDENTIAL

                       UNITED STATES COURT OF APPEALS
                            FOR THE THIRD CIRCUIT
                                 _____________

                                     No. 16-3365
                                    _____________

                           UNITED STATES OF AMERICA

                                           v.

                                    JAVIER PEREZ,
                                             Appellant
                                    ______________

                    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
                                   ______________

                                 Argued May 10, 2017
                                   ______________

             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
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

                                     ______________

                                        OPINION*
                                     ______________

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.
                                             2
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



                                              3
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 non-

identity 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, 

, 479 (1976) (quoting Coolidge v. New Hampshire, 

, 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, 

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



       1
           We have jurisdiction under 28 U.S.C. § 1291.
                                             4
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, 

, 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.”

.

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

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

, 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, 

,

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, 

, 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. 

       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

                                              5
Magistrate Judges in issuing or approving warrants for digital storage spaces. United

States v. Comprehensive Drug Testing, Inc., 

(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., 

(9th Cir. 2010) (en banc) (per curiam) (“CDT III”); 

(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, 

,

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, 

, 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, 

, 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, 

, 1273 (10th Cir. 1999).

                                             6
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, 

, 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 

; see also 

(6th Cir. 2011) (Nelson Moore, J., concurring in

the judgment); see also 

.

         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.

                                        *      *      *



                                               7
       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, 

, 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. 

.

       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, 

, 886 (3d Cir. 1992). Perez argues

                                              8
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, 

, 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.




                                              9