announced the judgment of the Court and delivered an opinion, in which Mr. Justice Stewart joined.
Having lawfully acquired possession of a dozen cartons of motion pictures, law enforcement officers viewed several reels of 8-millimeter film on a Government projector. Labels on the individual film boxes indicated that they contained obscene pictures. The question is whether the Fourth Amendment required the agents to obtain a warrant before they screened the films.
Only a few of the bizarre facts need be recounted. On September 25, 1975, 12 large, securely sealed packages containing 871 boxes of 8-millimeter film depicting homosexual activities were shipped by private carrier from St. Petersburg, Fla., to Atlanta, Ga. The shipment was addressed to “Leggs, Inc.,” 1 but was mistakenly delivered to a substation in the suburbs of Atlanta, where “L’Eggs Products, Inc.,” regularly received deliveries. Employees of the latter company opened *652each of the packages, finding the individual boxes of film. They examined the boxes, on one side of which were suggestive drawings, and on the other were explicit descriptions of the contents. One employee opened one or two of the boxes, and attempted without success to view portions of the film by holding it up to the light.2 Shortly thereafter, they called a Federal Bureau of Investigation agent who picked up the packages on October 1,1975.
Thereafter, without making any effort to obtain a warrant or to communicate with the consignor or the consignee of the shipment, FBI agents viewed the films with a projector. The record does not indicate exactly when they viewed the films, but at least one of them was not screened until more than two months after the FBI had taken possession of the shipment.3
On April 6, 1977, petitioners were indicted on obscenity charges relating to the interstate transportation of 5 of the 871 films in the shipment. A motion to suppress and return the films was denied, and petitioners were convicted on multiple counts of violating 18 U. S. C. §§ 371, 1462, and 1465. Over Judge Wisdom’s dissent, the Court of Appeals for the Fifth Circuit affirmed, 592 F. 2d 788, and rehearing was denied, 597 F. 2d 63 (1979). We granted certiorari, 444 U. S. 914,4 and now reverse.
*653In his concurrence in Stanley v. Georgia, 394 U. S. 557, 569, Mr. Justice Stewart expressed the opinion that the war-rantless projection of motion picture films was an unconstitutional invasion of the privacy of the owner of the films. After noting that the agents in that case were lawfully present in the defendant’s home pursuant to a warrant to search for wagering paraphernalia, Mr. Justice Stewart wrote:
“This is not a case where agents in the course of a lawful search came upon contraband, criminal activity, or criminal evidence in plain view. For the record makes clear that the contents of the films could not be determined by mere inspection. . . . After finding them, the agents spent some 50 minutes exhibiting them by means of the appellant’s projector in another upstairs room. Only then did the agents return downstairs and arrest the appellant.
“Even in the much-criticized case of United States v. Rabinowitz, 339 U. S. 56, the Court emphasized that 'exploratory searches . . . cannot be undertaken by officers with or without a warrant.’ Id., at 62. This record presents a bald violation of that basic constitutional rule. To condone what happened here is to invite a government official to use a seemingly precise and legal warrant only as a ticket to get into a man’s home, and, once inside, to launch forth upon unconfined searches and indiscriminate seizures as if armed with all the unbridled and illegal power of a general warrant.
“Because the films were seized in violation of the Fourth and Fourteenth Amendments, they were inadmis*654sible in evidence at the appellant’s trial.” Id., at 571-572 (footnote omitted).
Even though the cases before us involve no invasion of the privacy of the home, and notwithstanding that the nature of the contents of these films was indicated by descriptive material on their individual containers, we are nevertheless persuaded that the unauthorized exhibition of the films constituted an unreasonable invasion of their owner’s constitutionally protected interest in privacy. It was a search; there was no warrant; the owner had not consented; and there were no exigent circumstances.
It is perfectly obvious that the agents’ reason for viewing the films was to determine whether their owner was guilty of a federal offense. To be sure, the labels on the film boxes gave them probable cause to believe that the films were obscene and that their shipment in interstate commerce had offended the federal criminal code. But the labels were not sufficient to support a conviction and were not mentioned in the indictment. Further investigation — that is to say, a search of the contents of the films — was necessary in order to obtain the evidence which was to be used at trial.
The fact that FBI agents were lawfully in possession of the boxes of film did not give them authority to search their contents. Ever since 1878 when Mr. Justice Field’s opinion for the Court in Ex parte Jackson, 96 U. S. 727, established that sealed packages in the mail cannot be opened without a warrant, it has been settled that an officer’s authority to possess a package is distinct from his authority to examine its contents.5 See Arkansas v. Sanders, 442 U. S. 753, 758; United *655States v. Chadwick, 433 U. S. 1, 10. When the contents of the package are books or other materials arguably protected by the First Amendment, and when the basis for the seizure is disapproval of the message contained therein, it is especially important that this requirement be scrupulously observed.6
*656Nor does the fact that the packages and one or more of the boxes had been opened by a private party before they were acquired by the FBI excuse the failure to obtain a search warrant. It has, of course, been settled since Burdeau v. McDowell, 256 U. S. 465, that a wrongful search or seizure conducted by a private party does not violate the Fourth Amendment and that such private wrongdoing does not deprive the government of the right to use evidence that it has acquired lawfully. See Coolidge v. New Hampshire, 403 U. S. 443, 487-490. In these cases there was nothing wrongful about the Government’s acquisition of the packages or its examination of their contents to the extent that they had already been examined by third parties. Since that examination had uncovered the labels, and since the labels established probable cause to believe the films were obscene, the Government argues that the limited private search justified an unlimited official search. That argument must fail, whether we view the official search as an expansion of the private search or as an independent search supported by its own probable cause.
When an official search is properly authorized — whether by consent or by the issuance of a valid warrant — the scope of the search is limited by the terms of its authorization.7 Consent *657to search a garage would not implicitly authorize a search of an adjoining house; a warrant to search for a stolen refrigerator would not authorize the opening of desk drawers. Because “indiscriminate searches and seizures conducted under the authority of ‘general warrants’ were the immediate evils that motivated the framing and adoption of the Fourth Amendment,” Payton v. New York, 445 U. S. 573, 583, that Amendment requires that the scope of every authorized search be particularly described.8
If a properly authorized official search is limited by the particular terms of its authorization, at least the same kind of strict limitation must be applied to any official use of a private party’s invasion of another person’s privacy. Even though some circumstances — for example, if the results of the private search are in plain view when materials are turned over to the Government — may justify the Government’s reexamination of the materials, surely the Government may not exceed the scope of the private search unless it has the right to make an independent search. In these cases, the private party had not actually viewed the films. Prior to the Government screening, one could only draw inferences about what was on the films.9 The projection of the films was a significant expansion of the search that had been conducted previously by a private party and therefore must be characterized as a separate search. That separate search was not supported by any exigency, or by a warrant even though one could have easily been obtained.10
*658The Government claims, however, that because the packages had been opened by a private party, thereby exposing the descriptive labels on the boxes, petitioners no longer had any reasonable expectation of privacy in the films, and that the warrantless screening therefore did not invade any privacy interest protected by the Fourth Amendment. But petitioners expected no one except the intended recipient either to open the 12 packages or to project the films. The 12 cartons were securely wrapped and sealed, with no labels or markings to indicate the character of their contents.11 There is no reason why the consignor of such a shipment would have any lesser expectation of privacy than the consignor of an ordinary locked suitcase.12 The fact that the cartons were unexpectedly *659opened by a third party before the shipment was delivered to its intended consignee does not alter the consignor’s legitimate expectation of privacy. The private search merely frustrated that expectation in part.13 It did not simply strip the remaining unfrustrated portion of that expectation of all Fourth Amendment protection.14 Since the additional search conducted by the FBI — the screening of the films — was not supported by any justification, it violated that Amendment.
We therefore conclude that the rationale of Mr. Justice Stewart’s concurrence in Stanley v. Georgia, 394 U. S. 557, *660is applicable to these cases and that it requires that the judgments of the Court of Appeals be reversed.
It is so ordered.
Mr. Justice Marshall concurs in the judgment.
There was no “Leggs, Inc.” “Leggs” was the nickname of a woman employed by one of petitioners’ companies. The packages indicated that the intended recipient would pick them up and pay for them at the carrier’s terminal in Atlanta.
Each reel was eight millimeters in width. Petitioner Walter informs us that, excluding three millimeters for sprocketing and one millimeter for the border, the film itself is only four millimeters wide. Brief for Petitioner in No. 79-67, p. 30, n. 8. Since the scenes depicted within the frame are necessarily even more minute, it is easy to understand why such films cannot be examined successfully with the naked eye.
The FBI had meanwhile received no request from the consignee or the consignor of the films for their return, but the agents had been told by employees of L’Eggs Products, Inc., that inquiries had been made as to their whereabouts.
The petition for certiorari in No. 79-67 presented 10 separate questions, and the petition in No. 79-148 presented 5 separate questions. Except *653with respect to the issues discussed in the text, we have determined that certiorari was improvidently granted. We therefore dismiss as to the other questions that have been briefed and argued. For purposes of decision, we accept the Government’s argument that the delivery of the films to the FBI by a third party was not a “seizure” subject to the warrant requirement of the Fourth Amendment.
“In th[e] enforcement [of regulations as to what may be transported in the mails], a distinction is to be made between different kinds of mail matter, — between what is intended to be kept free from inspection, such as letters, and sealed packages subject to letter postage; and what is open to inspection, such as newspapers, magazines, pamphlets, and other printed matter, purposely left in a condition to be examined. Letters and *655sealed packages of this kind in the mail are as fully guarded from examination and inspection, except as to their outward form and weight, as if they were retained by the parties forwarding them in their own domiciles. The constitutional guaranty of the right of the people to be secure in their papers against unreasonable searches and seizures extends to their papers, thus closed against inspection, wherever they may be. Whilst in the mail, they can only be opened and examined under like warrant, issued upon similar oath or affirmation, particularly describing the thing to be seized, as is required when papers are subjected to search in one’s own household. No law of Congress can place in the hands of officials connected with the postal service any authority to invade the secrecy of letters and such sealed packages in the mail; and all regulations adopted as to mail matter of this kind must be in subordination to the great principle embodied in the fourth amendment of the Constitution.” 96 U. S., at 732-733.
And later in his opinion, Mr. Justice Field again noted that “regulations excluding matter from the mail cannot be enforced in a way which would require or permit an examination into letters, or sealed packages subject to letter postage, without warrant, issued upon oath or affirmation, in the search for prohibited matter. . . .” Id., at 735.
“This is the history which prompted the Court less than four years ago to remark that ‘[t]he use by government of the power of search and seizure as an adjunct to a system for the suppression of objectionable publications is not new.’ Marcus v. Search Warrant, 367 U. S. 717, at 724. ‘This history was, of course, part of the intellectual matrix within which our constitutional fabric was shaped. The Bill of Rights was fashioned against the background of knowledge that unrestricted power of search and seizure could also be an instrument for stifling liberty of expression.’ Id., at 729. As MR. Justice Douglas has put it, ‘The commands of our First Amendment (as well as the prohibitions of the Fourth and the Fifth) reflect the teachings of Entick v. Carrington, [19 How. St. Tr. 1029 (1765)]. These three amendments are indeed closely related, safeguarding not only privacy and protection against self-incrimination *656but "conscience and human dignity and freedom of expression as well.”’ Frank v. Maryland, 359 U. S. 360, 376 (dissenting opinion).
“In short, what this history indispensably teaches is that the constitutional requirement that warrants must particularly describe the ‘things to be seized’ is to be accorded the most scrupulous exactitude when the ‘things’ are books, and the basis for their seizure is the ideas which they contain.” Stanford v. Texas, 379 U. S. 476, 484-485.
See also Roaden v. Kentucky, 413 U. S. 496, 501. Although there were 871 reels of film in the shipment, there were only 25 different titles. Since only five of the titles were used as a basis for prosecution, it may be presumed that the other films were not obscene.
“The requirement that warrants shall particularly describe the things to be seized makes general searches under them impossible and prevents the seizure of one thing under a warrant describing another.” Manon v. United States, 275 U. S. 192, 196.
The Warrant Clause of the Fourth Amendment expressly provides that no warrant may issue except those “particularly describing the place to be searched, and the persons or things to be seized.”
Since the viewing was first done by the Government when it screened the films with a projector, we have no occasion to decide whether the Government would have been required to obtain a warrant had the private party been the first to view them.
The fact that the labels on the boxes established probable cause to believe the films were obscene clearly cannot excuse the failure to obtain a *658warrant; for if probable cause dispensed with the necessity of a warrant, one would never be needed.
Contrary to the dissent, post, at 665-666, n. 3, there were no impracticalities in these cases that would vitiate the warrant requirement. The inability to serve a warrant on the owner of property to be searched does not make execution of the warrant unlawful. See ALI, Model Code of Pre-Arraignment Procedure §220.3 (4) (Prop. Off. Draft 1975). Obviously, such inability does not render a warrant unnecessary under the Fourth Amendment. Nor is it clear in these cases that it would have been impossible to serve petitioners with a search warrant had the FBI made any effort to find them prior to screening the films. See n. 3, supra.
For the same reason, one may not deem petitioners to have consented to the screening merely because the labels on the unexposed boxes were explicit.
Nor can petitioners’ failure to make a more prompt claim to the Gov- ■ emment for return of the films be fairly regarded as an abandonment of their interest in preserving the privacy of the shipment. As subsequent events have demonstrated, such a request could reasonably be expected to precipitate criminal proceedings. We cannot equate an unwillingness to invite a criminal prosecution with a voluntary abandonment of any interest in the contents of the cartons. In any event, the record in these cases does indicate that the defendants made a number of attempts to locate the films before they were examined by the FBI agents.
The consignor’s expectation of privacy in the contents of a carton delivered to a private carrier must be measured by the condition of the package at the time it was shipped unless there is reason to assume that *659it would be opened before it arrived at its destination. Thus, for example, if a gun case is delivered to a carrier, there could then be no expectation that the contents would remain private, cf. Arkansas v. Sanders, 442 U. S. 753, 764-765, n. 13; but if the gun case were enclosed in a locked suitcase, the shipper would surely expect that the privacy of its contents would be respected.
The dissent asserts, post, at 665, that “[a]ny subjective expectation of privacy on the part of petitioners was undone ... by their own actions and the private search.” But it is difficult to understand how petitioners’ subjective expectation of privacy could have been altered in any way by subsequent events of which they were obviously unaware.
A partial invasion of privacy cannot automatically justify a total invasion. As Learned Hand noted in a somewhat different context: “It is true that when one has been arrested in his home or his office, his privacy has already been invaded; but that interest, though lost, is altogether separate from the interest in protecting his papers from indiscriminate rummage, even though both are customarily grouped together as parts of the 'right of privacy.’ ” United States v. Rabinowitz, 176 F. 2d 732, 735 (CA2 1949), rev’d, 339 U. S. 56. Judge Hand’s view was ultimately vindicated in Chimel v. California, 395 U. S. 752, 768, which specifically disapproved this Court’s decision in Rabinowitz. See also Mr. Justice Stewart’s opinion concurring in the result in Stanley v. Georgia, 394 U. S. 557, 571-572, quoted supra, at 653-654.
It is arguable that a third party’s inspection of the contents of “private books, papers, memoranda, etc.” could be so complete that there would be no additional search by the FBI when it re-examines the materials. Cf. Burdeau v. McDowell, 256 U. S. 465, 470. But this is not such a case, because it was clearly necessary for the FBI to screen the films, which the private party had not done, in order to obtain the evidence needed to accomplish its law enforcement objectives.