First, [the government] argues that it must be allowed to make the mirror image copies as a matter of practical necessity and, according to the Government’s investigators, those mirror images were “the government’s property.” As explained above, practical considerations may well justify a reasonable accommodation in the manner of executing a search warrant, such as making mirror images of hard drives and permitting off-site review, but these considerations do not justify the indefinite retention of non-responsive documents. See Comprehensive Drug Testing, Inc., 621 F.3d at 1171. Without a warrant authorizing seizure of Ganias’s personal financial records, the copies of those documents could not become ipso facto “the government’s property” without running afoul of the Fourth Amendment.

Second, the Government asserts that by obtaining the 2006 search warrant, it cured any defect in its search of the wrongfully retained files. But this argument “reduces the Fourth Amendment to a form of words.” Silverthorne Lumber Co. v. United States, 251 U.S. 385, 392 (1920). In Silverthorne, the Government, “without a shadow of authority[,] went to the office of [the defendants’] company and made a clean sweep of all the books, papers and documents found there.” Id. at 390. The originals were eventually returned because they were unlawfully seized, but the prosecutor had made “[p]hotographs and copies of material papers” and used these to indict the defendants and obtain a subpoena for the original documents. Id. at 391. Justice Holmes succinctly summarized the Government’s argument supporting the constitutionality of its actions as follows: “[A]lthough of course its seizure was an outrage which the Government now regrets, it may study the papers before it returns them, copy them, and then may use the knowledge that it has gained to call upon the owners in a more regular form to produce them; that the protection of the Constitution covers the physical possession but not any advantages that the Government can gain over the object of its pursuit by doing the forbidden act.” Id.

Unsurprisingly, the Supreme Court rejected that argument: “The essence of a provision forbidding the acquisition of evidence in a certain way is that not merely evidence so acquired shall not be used before the Court but that it shall not be used at all” unless some exception applies. Id. at 392. The same rationale applies here. If the Government could seize and retain non-responsive electronic records indefinitely, so it could search them whenever it later developed probable cause, every warrant to search for particular electronic data would become, in essence, a general warrant.

Third, the Government argues that it must be permitted to search the mirror images in its possession because the evidence no longer existed on Ganias’s computers. But the ends, however, do not justify the means. The loss of the personal records is irrelevant in this case because the Government concedes that it never considered performing a new search of Ganias’s computers and did not know that the files no longer existed when it searched the mirror images in its possession. And even if it were relevant, the Fourth Amendment clearly embodies a judgment that some evidence of criminal activity may be lost for the sake of protecting property and privacy rights. See, e.g., United States v. Calandra, 414 U.S. 338, 361 (1974) (“The judges who developed the exclusionary rule were well aware that it embodied a judgment that it is better for some guilty persons to go free than for the [Government] to behave in forbidden fashion.”).

Fourth, the Government contends that returning or destroying the non-responsive files is “entirely impractical” because doing so would compromise the remaining data that was responsive to the warrant, making it impossible to authenticate or use it in a criminal prosecution. Appellee Br. at 34. We are not convinced that there is no other way to preserve the evidentiary chain of custody. But even if we assumed it were necessary to maintain a complete copy of the hard drive solely to authenticate evidence responsive to the original warrant, that does not provide a basis for using the mirror image for any other purpose.

Finally, the Government argues that Ganias’s failure to bring a motion for the return of property, pursuant to Federal Rule of Criminal Procedure 41(g), precludes him from seeking suppression now. Although the district court accepted this argument, we find no authority for concluding that a Rule 41(g) motion is a prerequisite to a motion to suppress. See Fed.R.Crim.P. 41(g) (“A person aggrieved … may move for the property’s return.” (emphasis added)); Fed.R.Crim.P. 41(h) (“A defendant may move to suppress evidence ….“ (emphasis added)). Imposing such a prerequisite makes little sense in this context, where Ganias still had the original computer files and did not need the Government’s copies to be returned to him. Moreover, we fail to see what purpose a Rule 41(g) motion would have served, given the Government’s position that non-responsive files in its possession could not feasibly have been returned or purged anyway.

Because the Government has demonstrated no legal basis for retaining the non-responsive documents, its retention and subsequent search of those documents were unconstitutional. The Fourth Amendment was intended to prevent the Government from entering individuals’ homes and indiscriminately seizing all their papers in the hopes of discovering evidence about previously unknown crimes. See Entick, 95 Eng. Rep. at 817–18; see also Jones, 132 S.Ct. at 949. Yet this is exactly what the Government claims it may do when it executes a warrant calling for the seizure of particular electronic data relevant to a different crime. Perhaps the “wholesale removal” of intermingled computer records is permissible where off-site sorting is necessary and reasonable, Tamura, 694 F.2d at 595–97, but this accommodation does not somehow authorize the Government to retain all non-responsive documents indefinitely, for possible use in future criminal investigations. See Comprehensive Drug Testing, 621 F.3d at 1171.