Matthew Eric Mann entered a conditional guilty plea to one count of possessing child pornography in violation of 18 U.S.C. § 2252(a)(4)(B). The district court sentenced Mann to sixty-three months imprisonment to be followed by five years of supervised release. Police discovered evidence supporting the child pornography charges while executing a warrant to search Mann’s computers and hard drives for the unrelated crime of voyeurism. Mann preserved the right to appeal the district court’s denial of his motion to suppress the child pornography on the grounds that the search exceeded the scope of the warrant. Although we are troubled by some aspects of the search, we ultimately conclude that, with one immaterial exception, the officer executing the search did not exceed the scope of the original warrant.
I.
While working as a life guard instructor in May 2007 for the Red Cross in Tippecanoe County, Indiana, Mann covertly installed a video camera in the women’s locker room to capture footage of women changing their clothes. Unfortunately for Mann, he also captured footage of himself installing the camera in an open locker. One of the female students in his class later discovered the camera. She recognized Mann in the video when she rewound and viewed the tape. She and two other women in Mann’s class contacted the Lafayette Police Department and turned over the video camera and the videotape.
Three days later, an Indiana state prosecutor sought and received a search warrant for officers to search Mann’s residence for “video tapes, CD’s or other di *781 gital media, computers, and the contents of said computers, tapes, or other electronic media, to search for images of women in locker rooms or other private areas.” As relevant here, officers executing the warrant seized a Dell desktop computer with a Samsung hard drive, a Dell laptop, an e-machine, and a Western Digital external hard drive. The following day officers arrested Mann and charged him with voyeurism in violation of the Indiana Code. See Ind.Code Ann. § 35-45-4r-5(a)(2)(b)(l) (defining voyeurism and making it a class D felony when committed by means of any type of video recording device).
Nearly two months later, at the end of July 2007, Detective Paul Huff of the Lafayette Police Department began his search of Mann’s computers. At the suppression hearing, Detective Huff testified that he searched the computers by first using a “write blocker” to protect the hard drives from being altered and then created an exact match of each hard drive. He then used software known as “forensic tool kit” (“FTK”) to catalogue the images on the computer into a viewable format. Detective Huff explained that once this indexing process using FTK is completed, an “overview screen” is generated that lets him know how many images, videos, and documents are on the computer and whether there are encrypted documents or files that may be ignored (such as program files). The overview screen also lists files flagged by the software as “KFF (Known File Filter) Alert” and “KFF Ignorable” files. The “KFF Alert” flags those files identifiable from a library of known files previously submitted by law enforcement-most of which are images of child pornography.
On the first computer, Detective Huff discovered evidence that Mann had visited a web site called “Perverts Are Us,” where he had read and possibly downloaded stories about child molestation. On the Dell laptop, Detective Huff uncovered still images taken in the Jefferson High school locker room, child pornography, and evidence that the Western Digital external hard drive had been connected to the laptop. Detective Huff then searched the final computer, where he again found child pornography, along with a disturbing story (presumably written by Mann) about a swim coach masturbating while watching young girls swim.
It was not until nearly another two months later, on September 18, 2007, that Detective Huff first searched the Western Digital external hard drive. As with the other computers, Detective Huff used FTK to index the contents of the hard drive. The FTK software identified four “KFF Alert” files and 677 “flagged thumbnails.” Detective Huff proceeded to open the files on the computer and discovered “many, many images of child pornography” as well as two videos from the Jefferson High School locker room.
Mann moved in the district court to suppress all of the evidence seized from his home and computers as a result of the May 2007 warrant, arguing that the warrant lacked probable cause and that the executing officers exceeded the scope of the warrant’s authorization. The district court denied Mann’s motion, concluding that the magistrate judge had probable cause to issue the warrant based on the evidence of Mann’s voyeurism at Jefferson High School and the probability that Mann possessed evidence of his crime at his residence. The district court also rejected Mann’s claim that the executing officers had exceeded the scope of the warrant when they opened the files containing child pornography. Specifically, the district court found as a factual matter that Detective Huff believed the search warrant authorized him to examine any digital file *782 located on the computer hard drives or storage devices and that he never abandoned his search for evidence of voyeurism and began looking for child pornography. The court ultimately concluded that “with limited exceptions” the search was within the scope of the warrant, and that any images uncovered outside the scope of the warrant were discovered in plain view. Mann then entered a conditional guilty plea to the one count of possession of child pornography in the indictment, reserving his right to challenge on appeal the district court’s denial of his motion to suppress.
II.
On appeal, Mann maintains that the district court erred by denying his motion to suppress. In particular, Mann claims that the searches that uncovered the child pornography on his computer exceeded the scope of the original warrant and that the plain view doctrine does not apply on these facts. The government insists that the searches did not exceed the scope of the original warrant, and that the incriminating child pornography was in any event discovered in plain view. When reviewing a motion to suppress, we review the district court’s legal conclusions de novo and its factual findings for clear error. E.g., United States v. Marrocco, 578 F.3d 627, 632 (7th Cir.2009).
We begin with Mann’s contention that Detective Huffs search of the computers exceeded the scope of the warrant. The Fourth Amendment requires that a warrant describe the things to be seized with sufficient particularity to prevent a general exploratory rummaging through one’s belongings.
See, e.g., Marron v. United States, 275
U.S. 192, 196,
Mann maintains that given the warrant’s directive to search in those places likely to contain “images of women in locker rooms and other private places,” it was unreasonable for Detective Huff to employ the FTK software and its accompanying “KFF Alert” system, which ordinarily identifies files containing child pornography. Undoubtedly the warrant’s description serves as a limitation on what files may reasonably be searched. The problem with applying this principle to computer searches lies in the fact that such images could be nearly anywhere on the computers. Unlike a physical object that can be immediately identified as responsive to the warrant or not, computer files may be manipulated to hide their true contents.
See United States v. Hill,
So although the officers were limited by the warrant to a search likely to yield “images of women in locker rooms and other private places,” those images could *783 be essentially anywhere on the computer. Detective Huff testified at the suppression hearing that “[rjegardless of what I found, I would search in all the files if I felt it necessary, if I felt that it contained information that was pertinent to my case or even exculpatory.” Thus, the government’s argument goes, Detective Huff was at all relevant times searching for the type of image detailed in the warrant, and the fact that he uncovered child pornography does not invalidate the lawful search.
Mann, however, maintains that Detective Huff ignored the limitations in the warrant and instead conducted a general search for crimes unrelated to voyeurism. Mann relies heavily on a Tenth Circuit decision,
United States v. Carey,
More recently, the Tenth Circuit decided
United States v. Burgess,
In particular, the court in
Carey
premised its holding on a few key facts that are absent here. First, the warrant in
Carey
authorized a search of the computer solely for “documentary” evidence of drug dealing; thus, the court found it significant that officers downloaded and viewed numerous image files containing child pornography.
Id.
at 1271, 1273 (noting that “scope of the search was ... circumscribed to evidence pertaining to drug trafficking”). In contrast, Officer Mann was searching for “images” of women — a type of file that he could not search thoroughly for without stumbling upon Mann’s extensive collection of child pornography. In this respect, the search of Mann’s computer more closely resembles the search in
Wong,
where the Ninth Circuit upheld the denial of a motion to suppress child por
*784
nography found on a defendant’s computer incident to a murder investigation.
United States v. Wong,
Second, the court in
Carey
found as a factual matter that the officer conducting the search “made clear as he opened each of the JPG files he was not looking for evidence of drug trafficking” and had “abandoned that search to look for more child pornography.”
Carey,
Additionally, we note that Mann’s primary complaint with Detective Huffs search — that he used FTK software employing a filter and viewed those files flagged with the “KFF Alert” — does not impact the outcome here. First, as to the use of the filtering software itself, Detective Huff used it to index and catalogue the files into a viewable format. Given the nature of Detective Huffs search and the fact that Mann could have images of women in locker rooms virtually anywhere on his computers, there is no reason to believe that Detective Huff exceeded the scope of the warrant by employing the FTK software without more.
But see United States v. Comprehensive Drug Testing, Inc.,
*785
Unfortunately for Mann, suppressing those four images has no impact on the outcome here. Without those images, the government still possessed ample evidence of child pornography to sustain both Mann’s conviction and sentence. Although we hold that Officer Huff exceeded the scope of the warrant by opening the four flagged “KFF Alert” flies, those files are severable from the remaining files seized.
See United States v. Buckley,
We also reject Mann’s suggestion that we take our cue from the more comprehensive rules regarding computer searches recently outlined by the Ninth Circuit. In
United States v. Comprehensive Drug Testing, Inc.,
an en banc panel of the Ninth Circuit rejected the government’s attempt to justify its seizure of drug testing records for hundreds of Major League Baseball Players despite a warrant authorizing the seizure of only ten players’ records.
Mann urges us to apply the Ninth Circuit’s rationale to conclude that Detective Huffs search was unconstitutional. Although the Ninth Circuit’s rules provide some guidance in a murky area, we are inclined to find more common ground with the dissent’s position that jettisoning the plain view doctrine entirely in digital evidence cases is an “efficient but overbroad approach.” Id. at 1013 (Callahan, J., concurring in part and dissenting in part). As the dissent recognizes, there is nothing in the Supreme Court’s case law (or the Ninth Circuit’s for that matter) counseling the complete abandonment of the plain view doctrine in digital evidence cases. Id. We too believe the more considered approach “would be to allow the contours of the plain view doctrine to develop incrementally through the normal course of fact-based case adjudication.” Id. We are also skeptical of a rule requiring officers to always obtain pre-approval from a magistrate judge to use the electronic tools necessary to conduct searches tailored to uncovering evidence that is responsive to a properly circumscribed warrant.
*786
Instead, we simply counsel 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. As discussed above, with the exception of the four “KFF Alert” images, Detective Huffs search was indeed targeted to uncovering evidence of voyeurism as described in what Mann now concedes was a lawful warrant.
2
In so doing, he uncovered obvious evidence of child pornography. Although we now hold that his actions were within the scope of the warrant, we emphasize that his failure to stop his search and request a separate warrant for child pornography is troubling.
Burgess,
For the foregoing reasons we AFFIRM the judgment of the district court denying Mann’s motion to suppress.
Notes
. The Ninth Circuit recently (November 4, 2009) entered an order asking the parties in this case to brief the question of whether the case should be reheard by the full en banc court (comprised of all active judges as opposed to the 11 ordinarily selected randomly for standard en banc review).
. Although Mann argued in the district court that the warrant lacked probable cause, he has since abandoned that challenge.
