Justin Hill conditionally pled guilty to possession of child pornography subject to his challenge to the admission of evidence that he contends was seized in violation of the Fourth Amendment. His appeal involves the validity of a warrant to search his computer and storage media for evidence that he possessed pornographic (i.e., lascivious) images of children. We must also decide whether it was reasonable under the Fourth Amendment for the police to take all of Hill’s computer storage media from his home (they did not find his computer) so they could conduct their search offsite in a police laboratory, rather than carrying out the search onsite and taking only whatever evidence of child pornography they might find. As we recently discussed in
United States v. Adjani,
I. Background
As the district court explained:
A computer technician was repairing defendant’s computer when she discovered what she believed to be child pornography. She called Long Beach police, and the detective who took the call obtained a search warrant from a judge of the Long Beach Superior Court. The warrant authorized a search of the computer repair store and seizure of the computer, any work orders relating to the computer, “all storage media belonging to either the computer or the individual identifying himself as defendant at the location,” and “all sexually explicit images depicting minors contained in the storage media.” By the time the detective arrived at the store to execute the warrant, defendant had picked up his computer.... [T]he detective [submitted an affidavit, which included the computer technician’s sworn statement describing the images. On the basis of this affidavit, the officer obtained] a second warrant, this one directed at defendant’s home, authorizing seizure of the same items.
The affidavit on which the warrants were based described “two images of child pornography”:
Image 1
Is a color picture of a female, white, approximately 15 years old, with long dark brown hair. The female is in a room standing between a couch and a coffee table. There is a framed picture on the wall above the couch. She is wearing only a long blouse and pair of socks. The blouse is open and she is exposing her breast and pubic area to the camera, which she is facing while leaning to her left.
Image 2
Is a color picture of a [sic in affidavit] two females, white, approximately 7-9 *969 years of age, both with dirty blond hair. These females are standing on a beach during the daytimе. The shorter of the two females is standing to the right of the picture while the other female is standing behind her. Both females are facing the camera askew and wearing only a robe, which is open exposing the undeveloped breast and pubic area of both girls. They both are turning then-faces away from the camera preventing the viewer from seeing their faces. Officers executed the search warrant but did not find the computer in defendant’s apartment. 1 In what appeared to be defendant’s bedroom, they found and seized computer storage media[, specifically: 22 5.25-inch floppy disks, two CD-ROMs, 124 3.5-inch floppy disks and six zip disks.] [Two of the zip disks] were eventually determined to contain images of child pornography; [officers] also seized other evidence consistent with the warrаnt. Defendant was subsequently charged with one count of possession of child pornography, 2 in violation of 18 U.S.C. § 2252A(a)(5)(B). 3
Hill,
In the district court, the defendant moved to suppress the evidence recovered from the two zip disks on the grounds that, (1) contrary to the magistrate’s finding, the warrant affidavit did not establish probable cause to believe the defendant was guilty of criminal activity; and (2) the warrant was overbroad in allowing seizure of all discovered computer storage media with no regard to whether such media contained child pornography, and in placing no limitation on the police officers’ search of the seized disks. Id. at 1084. 4 *970 The district court denied the motion to suppress and the defendant conditionally-pled guilty to the charge, reserving the right to appeal the district court’s eviden-tiary ruling. 5 This timely appeal followed.
II. Standard of Review
We review de novо the district court’s denial of a motion to suppress evidence.
United States v. Meek,
III. Discussion
A. Probable Cause
The defendant argues first that the affidavit submitted in support of the search warrant was insufficient to establish probable cause to believe the defendant was guilty of criminal activity. We do not agree.
“[N]o Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.” U.S. Const, amend. IV. The Constitution is clear; a magistrate may authorize a search of a location only if officers establish probable cause to believe evidence of a crimfe may be found there. Probable cause means only a “fair probability,” not certainty, and requires consideration of the totality of the circumstances.
Illinois v. Gates,
Child pornography is a particularly repulsive crime, but not all images of nude children are pornographic. For example, “a family snаpshot of a nude child bathing presumably would not” be criminal.
Hill,
Various courts have attempted to articulate a test for determining lasciviousness. Many have relied upon a six-factor test originated in United States v. Dost:
(1) whether the focal point of the visual depiction is on the child’s genitalia or pubic area;
(2) whether the setting of the visual depiction is sexually suggestive, i.e., in a place or pose generally associated with sexual activity;
(3) whether the child is dеpicted in an unnatural pose, or in inappropriate attire, considering the age of the child;
(4) whether the child is fully or partially clothed, or nude;
(5) whether the visual depiction suggests sexual coyness or a willingness to engage in sexual activity;
(6) whether the visual depiction is intended or designed to elicit a sexual response in the viewer.
The district court, analyzing each of these six factors, found
Dost
to be “not particularly helpful” in determining whether a given image is lascivious — generally or as applied to the images here.
See Hill,
The
Dost
factors can be a starting point for judges to use in determining whether a particular image is likely “so presented by the photographer as to arouse or satisfy the sexual cravings of a voyeur.”
Wiegand,
Ultimately, probable cause is a fluid and nontechnical conception not readily suscep-tibie to multifactor tests or rebuttable presumptions.
See Maryland v. Pringle,
Based on our independent review of the affidavit describing the two images, we are satisfied that the state judge’s finding of probable cause was well within his discretion. There was a fair probability that the images were “so presented by the photographer as tо arouse or satisfy the sexual cravings of a voyeur.”
Wiegand,
B. Overbreadth
1. Seizure of All Computer Media
The defendant argues that the search warrant was overbroad because it authorized the officers to seize and remove from his home his computer and storage media without first determining whether they actually contained child pornography. Given the nature of computers and storage media, this argument sweeps too broadly, as the district court explained in addressing the defendant’s suggested limitations on the nature and scope of the search:
Search warrants must be specific. “Specificity has two aspects: particularity and breadth. Particularity is the requirement that the warrant must clearly state what is sought. Breadth deals with the requirement that the scope of the warrant be limited by the probable cause on which the warrant is based.” United States v. Towne,997 F.2d 537 , 544 (9th Cir.1993) (internal quotation marks and citations omitted). A warrant describing a category of items is not invalid if a more specific description is impossible. United States v. Spilotro,800 F.2d 959 , 963 (9th Cir.1986). The level of specificity required “varies depending on the circumstances of the case and the type of items involved.” Id. The warrant here commanded the officers to search for and seize: “1) An IBM ‘clone’ medium tower personal computer ... 3) All storage media belonging to either item # 1 or the individual identifying himself as defendant at the location. 4) All sexually explicit images depicting minors contained in item # 3.” Defendant argues the warrant was overbroad because it authorized seizure of storage media whether or not they contained child pornography. He suggests it should have authorized seizure only of media containing child pornography. But it is impossible to tell what a computer storage medium contains just by looking at it. Rather, one has to examine it electronically, using a computer that is running the appropriate operating system, hardware and software. The police had no assurance they would find such a computer at the scene — nor did they, for that matter — or that, if they found one, they could bypass any security measures and operate it.
*974 Defendant suggests that the police could have brought their own laptop computer: Having probable cause to seize only computer storage media that contаined certain types of files, the police should have been required to bring with them the equipment necessary to separate the sheep from the goats. Defendant’s argument raises an important question about how police must execute seizures pursuant to a warrant. Because seiza-ble materials are seldom found neatly separated from their non-seizable counterparts, how much separating must police do at the scene to avoid taking items that are neither contraband nor evidence of criminal activity?
As always under the Fourth Amendment, the standard is reasonableness. To take an extreme example, if police have probable cause to seize business records, the warrant could not authorize seizure of every piece оf paper on the premises on the theory that the police conducting the search might not know how to read....
[T]he court concludes that the police were not required to bring with them equipment capable of reading computer storage media and an officer competent to operate it. Doing so would have posed significant technical problems and made the search more intrusive. To ensure that they could access any electronic storage medium they might find at the scene, police would have needed far more than an ordinary laptop computer. Because computers in common use run a variety of operating systems— various versions or flavors of Windows, Mac OS and Linux, to name only the most common — police would have had to bring with them a computer (or computers) equipped to read not only all of the major media types, but also files encoded by all major operating systems. Because operating systems, media types, file systems and file types are continually evolving, police departments would frequently have to modify their computers to keep them up-to-date. This would not be an insuperable obstacle for larger police departments and federal law enforcement agencies, but it would pose a significant burden on smaller agencies.
Even if the police were to bring with them a properly equipped computer, and someone competent to operate it, using it would pose two significant problems. First, there is a serious risk that the police might damage the storage medium or compromise the integrity of the evidence by attempting to access the data at the scene. As everyone who has accidentally erased a computer file knows, it is fairly easy to make mistakes when operating computer equipment, especially equipment one is not intimately familiar with. The risk that the officer trying to read the suspect’s storage medium on the police laptop will make a wrong move and erase what is on the disk is not trivial. Even if the officer executes his task flawlessly, there might be a power failure or equipment malfunction that could affect the contents of the medium being searched. For that reason, experts will make a back-up copy of the medium before they start manipulating its contents. Various other technical problems might arise; without the necessary tools and expertise to deal with them, any effort to read computer flies at the scene is fraught with difficulty and risk.
Second, the process of searching the files at the scene can take a long time. To be certain that the medium in question does not contain any seizable material, the officers would have to examine every one of what may be thousands of files on a disk — a process that could take *975 many hours and perhaps days. Taking that much time to conduct the search would not only impose a significant and unjustified burden on police resources, it would also make the search more intrusive. Police would have to be present on the suspect’s premises while the search was in progress, and this would necеssarily interfere with the suspect’s access to his home or business. If the search took hours or days, the intrusion would continue for that entire period, compromising the Fourth Amendment value of making police searches as brief and non-intrusive as possible.
Hill,
We agree with the district court that under the circumstances here, the warrant was not fatally defective in failing to require an onsite search and isolation of child pornography before removing storage media wholesale. That does not mean, however, that the government has an automatic blank check when seeking or executing warrants in computer-related searches. Although computer technology may in theory justify blanket seizures for the reasons discussed above, the government must still demonstrate to the magistrate factually why such a broad search and seizure authority is reasonable in the case at hand. There may well be situations where the government has no basis for believing that a computer search would involve the kind of technological problems that would make an immediate onsite search and selective removal of relevant evidence impracticable. Thus, there must be some threshold showing before the government may “seize the haystack to look for the needle.”
Our eases illustrate this principle. In
United States v. Hay,
for example, we held permissible a “generic classification” authorizing seizure of an “entire computer system and virtually every document in [the defendant’s] possession without referencing child pornography or any particular offense conduct” because, although officers “knew that[a party] hаd sent 19 images [of child pornography] directly to[the defendant’s] computer, [they] had no way of knowing where the images were stored.”
By contrast, although the warrant in this case authorized a wholesale seizure, the supporting affidavit did not explain why such a seizure was necessary.
See United States v. Adjani,
We do not approve of issuing warrants authorizing blanket removal of all computer storage media for later examination when there is no affidavit giving a reasonable explanation, such as that provided in
Hay
and
Lacy,
as to why a wholesale seizure is necessary.
12
See Tamura,
Nonetheless, as in Tamura, we conclude that suppression of the evidence of child pornography found on the defendant’s seized zip disks is not an appropriate remedy. Tamura involved an indiscriminate seizure of all files found in an office even though the warrant authorized the officers to search for only three categories of records for evidence of various alleged crimes. See id. at 594-95. Although we refused to sanction the “wholesale seizure for later detailed examination of records not described in a warrant,” id. at 595, we held that “the exclusionary rule does not require the suppression of evidence within the scope of a warrant simply because other items outside the scope of the warrant were unlawfully taken as well,” id. at 597. See also id. (“Regardless of the illegality of the Government’s seizure and retention of documents not covered by the warrant, however, reversal is not compelled in this case.”).
Similarly, the pornographic images from the defendant’s zip disks that he sought to exclude as evidence at trial was “seized and retained lawfully because described in and therefore taken pursuant to the valid search warrant.”
Id.
As we have discussed above, the officers’ wholesale seizure was flawed here because they failed to justify it to the magistrate, not because they acted unreasonably or improperly in executing the warrant. Because the officers were “motivated by considerations of practicality rather than by a desire to engage in indiscriminate ‘fishing,’ we cannot say ... that the officers so abused the warrant’s authority that the otherwise valid warrant was transformed into a general one, thereby requiring all fruits to be suppressed.”
Id.See also Hudson v. Michigan,
547 U.S. -,
Therefore, we hold that the district court properly admitted the evidence of child pornography found on the defendant’s computer storage media notwithstanding the lack of a sufficiently detailed supporting affidavit describing the need for wholesale seizure of such media.
2. Absence of Search Protocol
The defendant also argues that the search warrant was overbroad because it did not include a search protocol to limit the officers’ discretion as to what they could examine when searching the defendant’s computer media, nor did the affidavit explain why such a protocol was unnecessary. We, like the district court, find no error in the search warrant on this ground and adopt the district court’s analysis:
Defendant also argues that the warrant was overbroad because it did not define a “search methodology.” He claims that the search should have been limited to certain files that are more likely to be associated with child pornography, such as those with a “.jpg” suffix (which usu *978 ally identifies files containing images) or those containing the word “sex” or other key words.
Defendant’s proposed search methodology is unreasonable. “Computer records are extremely susceptible to tampering, hiding, or destruction, whether deliberate or inadvertent.” United States v. Hunter,13 F.Supp.2d 574 , 583 (D.Vt. 1998). Images can be hidden in all manner of files, even word processing documents and spreadsheets. Criminals will do all they can to conceal contraband, including the simple expedient of changing the names and extensions of files to disguise their content from the casual observer.
Forcing police to limit their searches to files that the suspect has labeled in a particular way would be much like saying police may not seize a plastic bag containing a powdery white substance if it is labeled “flour” or “talcum powder.” There is no way to know what is in a file without examining its contents, just as there is no sure way of separating talcum from cocaine except by testing it. The ease with which child pornography images can be disguised — whether by renaming sexyteenyboppersxxxjpg as sundayschoollesson.doc, or something more sophisticated — forecloses defendant’s proposed search methodology.
Hill,
Moreover, in contrast to our discussion of the overbroad seizure claim above, there is no case law holding that an officer
must
justify the lack of a search protocol in order to support issuance of the warrant. As we have noted, we look favorably upon the inclusion of a search protocol; but its absence is not fatal. We have also held that even though a warrant authorizing a computer search might not contain a search protocol restricting the search to certain programs or file names, the officer is always “limited by the longstanding principle that a duly issued warrant, even one with a thorough affidavit, may not be used to engage in a general, exploratory search.”
Id.
The reаsonableness of the officer’s acts both in executing the warrant and in performing a subsequent search of seized materials remains subject to judicial review.
See United States v. Rettig,
*979 IV. Conclusion
We realize that judicial decisions regarding the application of the Fourth Amendment to computer-related searches may be of limited longevity. Technology is rapidly evolving and the concept of what is rеasonable for Fourth Amendment purposes will likewise have to evolve.
See Kyllo v. United States,
That said, for the reasons set forth in this opinion, the search here was supported by probable cause and, notwithstanding the shortcomings of the search warrant affidavit, the manner of its execution does not mandate suppression of the fruits of that search. The district court’s denial of the defendant’s motion to suppress is therefore AFFIRMED
Notes
. Or anywhere else: The computer was never found.
. 18 U.S.C. § 2256(8) defines "child pornography” as
any visual depiction, including any photograph, film, video, picture, or computer or computer-generated image or picture, whether made or produсed by electronic, mechanical, or other means, of sexually explicit conduct, where—
(A) the production of such visual depiction involves the use of a minor engaging in sexually explicit conduct;
(B) such visual depiction is a digital image, computer image, or computer-generated image that is, or is indistinguishable from, that of a minor engaging in sexually explicit conduct; or
(C) such visual depiction has been created, adapted, or modified to appear that an identifiable minor is engaging in sexually explicit conduct.
Section 2256(2)(B)(iii) defines "sexually explicit conduct” as "graphic or simulated lascivious exhibition of the genitals or pubic area of any person.” Thus, the lascivious exhibition of the genitals or pubic area of a minor constitutes child pornography. A portion of section 2256(8) that is irrelevant to the issues raised in these motions was held unconstitutional in Ashcroft v. Free Speech Coalition. See535 U.S. 234 ,122 S.Ct. 1389 ,152 L.Ed.2d 403 (2002).
. Section 2252A(a)(5)(B) prohibits:
knowingly possessing any book, magazine, periodical, film, videotape, computer disk, or any other material that contains an image of child pornography that has been mailed, or shipped or transported in interstate or foreign commerce by any means, including by computer, or that was produced using materials that have been mailed, or shipped or transported in interstate or foreign commerce by any means, including by computer.
. The defendant did not challenge the warrant affidavit on the ground that it included only a written description of the images and not the images themselves.
Cf. United States v. Battershell,
. In the district court, the defendant also argued that in order to prepare a defense his counsel and his expert were entitled to "mirror image” copies of the computer media the government seized. The district court agreed and ordered the government to provide defendant with copies.
Hill,
. We stress that in this case the state court judge who issued the warrant made his determination based upon a
written description
of the images. The officer presenting that description of the images had a duty, of course, to do so in good faith, providing all relevant information to the magistrate.
See United States v. Mendonsa,
. The defendant challenges only whether there was probable cause to believe the images described were lascivious, i.e., whether there was a fair probability that the defendant possessed evidence of a crime (child pornography). Assuming he loses the lasciviousness argument, he does not argue there was no probable cause to believe that such evidence could be found on his computer (or storage media).
Cf. Gourde,
. The district court's test might be an improvement over the
Dost
six-factor inquiry, at least when the magistrate can see and evaluate the images first hand. However, when (as
*972
here) the magistrate does not have the images, the judge would have to- determine whether "there are strong indicators that [the image] is not lascivious” based on the information the attesting officer (or, as in this case, a third-party witness) includes in the description. It is not clear that officers would be as able to decide and articulate what is relevant
mitigating
information (from the unrepresented target's viewpoint) as in making their affirmative showing of lasciviousness under existing doctrine.
Cf. Hill,
. Although the defendant at trial might have been able to present evidence supporting innocent explanations for the content of the pictures, that does not negate the images’ prima facie appearance of lasciviousness— which is the issue relevant to probable cause.
. In contrast to the concerns we raised in footnote 8, supra, the defendant does not argue that the affidavit’s description of the im-ages was incomplete in any way; nor does he claim that the attesting officer was aware of hut failed to disclose mitigating facts that would tend to show the images were not lascivious.
. In retrospect, it is clear that not all the storage media needed to be seized as evidence of criminal activity; of the 154 disks seized, only two zip disks contained lascivious images of children. There is no evidence or allegation that the officers knew of this result before they searched and seized.
. As the defendant pointed out during oral argument, the magistrate must be made aware of what officers are contemplating and why they are doing so. For some people, computer files are the exclusive means of managing one’s life — such as maintaining a calendar of appointments or paying bills. Thus, there may be significant collateral consequences resulting from a lengthy, indiscriminate seizure of all such files. As noted earlier, however, in this case the district court granted the defendant the right to "mirror copies” of the seized storage media. See supra n. 5.
. The district court found no violation because it assumed the state judge must have known it was not technologically feasible to search onsite, and therefore the affidavit did not need to so provide.
See Hill,
. As we noted in
Adjani,
