concurring in part and concurring in the judgment.
It is relatively easy for me to concur in the judgment in this case, since in my view the case should be judged on the basis of the Magistrate’s finding that, when the first DEA agent arrived, the “tube was in plain view in the box and the bags with the white powder were visible from the end of the tube.” App. to Pet. for Cert. 18a. Although this finding was challenged before the District Court, that court found it unnecessary to pass on the issue. Id., at 12a-13a. As I understand its opinion, however, the Court of Appeals accepted the Magistrate’s finding: the Federal Express manager “placed the bags back in the tube, leaving them visible from the tube’s end, and placed the tube back in the box”; he later gave the box to the DEA agent, who “removed the tube from the open box, took the bags out of the tube, and extracted a sample of the powder.” 683 F. 2d 296, 297 (CA8 1982). At the very least, the Court of Appeals assumed that *127the contraband was in plain view. The Court of Appeals then proceeded to consider whether the federal agent’s field test was an illegal extension of the private search, and it invalidated the field test solely for that reason.
Particularly since respondents argue here that whether or not the contraband was in plain view when the federal agent arrived is irrelevant and that the only issue is the validity of the field test, see, e. g., Brief for Respondents 25, n. 11; Tr. of Oral Arg. 28, I would proceed on the basis that the clear plastic bags were in plain view when the agent arrived and that the agent thus properly observed the suspected contraband. On that basis, I agree with the Court’s conclusion in Part III that the Court of Appeals erred in holding that the type of chemical test conducted here violated the Fourth Amendment.
The Court, however, would not read the Court of Appeals’ opinion as having accepted the Magistrate’s finding. It refuses to assume that the suspected contraband was visible when the first DEA agent arrived on the scene, conducts its own examination of the record, and devotes a major portion of its opinion to a discussion that would be unnecessary if the facts were as found by the Magistrate. The Court holds that even if the bags were not visible when the agent arrived, his removal of the tube from the box and the plastic bags from the tube and his subsequent visual examination of the bags’ contents “infringed no legitimate expectation of privacy and hence was not a ‘search’ within the meaning of the Fourth Amendment” because these actions “enabled the agent to learn nothing that had not previously been learned during the private search.” Ante, at 120 (footnote omitted). I disagree with the Court’s approach for several reasons.
First, as I have already said, respondents have abandoned any attack on the Magistrate’s findings; they assert that it is irrelevant whether the suspected contraband was in plain view when the first DEA agent arrived and argue only that the plastic bags could not be opened and their contents tested *128without a warrant. In short, they challenge only the expansion of the private search, place no reliance on the fact that the plastic bags containing the suspected contraband might not have been left in plain view by the private searchers, and do not contend that their Fourth Amendment rights were violated by the duplication of the private search they alleged in the District Court was necessitated by the condition to which the private searchers returned the package. In these circumstances, it would be the better course for the Court to decide the case on the basis of the facts found by the Magistrate and not rejected by the Court of Appeals, to consider only whether the alleged expansion of the private search by the field test violated the Fourth Amendment, and to leave for another day the question whether federal agents could have duplicated the prior private search had that search not left the contraband in plain view.
Second, if the Court feels that the Magistrate may have erred in concluding that the white powder was in plain view when the first agent arrived and believes that respondents have not abandoned their challenge to the agent’s duplication of the prior private search, it nevertheless errs in responding to that challenge. The task of reviewing the Magistrate’s findings belongs to the District Court and the Court of Appeals in the first instance. We should request that they perform that function, particularly since if the Magistrate’s finding that the contraband was in plain view when the federal agent arrived were to be sustained, there would be no need to address the difficult constitutional question decided today. The better course, therefore, would be to remand the case after rejecting the Court of Appeals’ decision invalidating the field test as an illegal expansion of the private search.
Third, if this case must be judged on the basis that the plastic bags and their contents were concealed when the first agent arrived, I disagree with the Court’s conclusion that the agent could, without a warrant, uncover or unwrap the tube *129and remove its contents simply because a private party had previously done so. The remainder of this opinion will address this issue.
The governing principles with respect to the constitutional protection afforded closed containers and packages may be readily discerned from our cases. The Court has consistently rejected proposed distinctions between worthy and unworthy containers and packages, United States v. Ross, 456 U. S. 798, 815, 822-823 (1982); Robbins v. California, 453 U. S. 420, 425-426 (1981) (plurality opinion), and has made clear that “the Fourth Amendment provides protection to the owner of every container that conceals its contents from plain view” and does not otherwise unmistakably reveal its contents. United States v. Ross, supra, at 822-823; see Robbins v. California, supra, at 427-428 (plurality opinion); Arkansas v. Sanders, 442 U. S. 753, 764, n. 13 (1979). Although law enforcement officers may sometimes seize such containers and packages pending issuance of warrants to examine their contents, United States v. Place, 462 U. S. 696, 701 (1983); Texas v. Brown, 460 U. S. 730, 749-750 (1983) (Stevens, J., concurring in judgment), the mere existence of probable cause to believe that a container or package contains contraband plainly cannot justify a warrantless examination of its contents. Ante, at 114; United States v. Ross, supra, at 809-812; Arkansas v. Sanders, supra, at 762; United States v. Chadwick, 433 U. S. 1, 13, and n. 8 (1977).
This well-established prohibition of warrantless searches has applied notwithstanding the manner in which the police obtained probable cause. The Court now for the first time sanctions warrantless searches of closed or covered containers or packages whenever probable cause exists as a result of a prior private search. It declares, in fact, that governmental inspections following on the heels of private searches are not searches at all as long as the police do no more than the private parties have already done. In reaching this conclusion, the Court excessively expands our prior decisions rec*130ognizing that the Fourth Amendment proscribes only governmental action. Burdeau v. McDowell, 256 U. S. 465 (1921); Coolidge v. New Hampshire, 403 U. S. 443, 487-490 (1971).
As the Court observes, the Fourth Amendment “is wholly inapplicable ‘to a search or seizure, even an unreasonable one, effected by a private individual not acting as an agent of the Government or with the participation or knowledge of any governmental official.’” Ante, at 113 (quoting Walter v. United States, 447 U. S. 649, 662 (1980) (Blackmun, J., dissenting)). Where a private party has revealed to the police information he has obtained during a private search or exposed the results of his search to plain view, no Fourth Amendment interest is implicated because the police have done no more than fail to avert their eyes. Coolidge v. New Hampshire, supra, at 489.
The private-search doctrine thus has much in common with the plain-view doctrine, which is “grounded on the proposition that once police are lawfully in a position to observe an item firsthand, its owner’s privacy interest in that item is lost . . . .” Illinois v. Andreas, 463 U. S. 765, 771 (1983) (emphasis added). It also shares many of the doctrinal underpinnings of cases establishing that “the Fourth Amendment does not prohibit the obtaining of information revealed to a third party and conveyed by him to Government authorities,” United States v. Miller, 425 U. S. 435, 443 (1976), although the analogy is imperfect since the risks assumed by a person whose belongings are subjected to a private search are not comparable to those assumed by one who voluntarily chooses to reveal his secrets to a companion.
Undoubtedly, the fact that a private party has conducted a search “that might have been impermissible for a government agent cannot render otherwise reasonable official conduct unreasonable.” Ante, at 114-115. But the fact that a repository of personal property previously was searched by a private party has never been used to legitimize governmental conduct that otherwise would be subject to challenge under *131the Fourth Amendment. If government agents are unwilling or unable to rely on information or testimony provided by a private party concerning the results of a private search and that search has not left incriminating evidence in plain view, the agents may wish to duplicate the private search to observe firsthand what the private party has related to them or to examine and seize the suspected contraband the existence of which has been reported. The information provided by the private party clearly would give the agents probable cause to secure a warrant authorizing such actions. Nothing in our previous cases suggests, however, that the agents may proceed to conduct their own search of the same or lesser scope as the private search without first obtaining a warrant. Walter v. United States, supra, at 660-662 (White, J., concurring in part and concurring in judgment).
Walter v. United States, on which the majority heavily relies in opining that “[t]he additional invasions of respondents’ privacy by the Government agent must be tested by the degree to which they exceeded the scope of the private search,” ante, at 115, does not require that conclusion. Justice Stevens’ opinion in Walter does contain language suggesting that the government is free to do all of what was done earlier by the private searchers. But this language was unnecessary to the decision, as Justice Stevens himself recognized in leaving open the question whether “the Government would have been required to obtain a warrant had the private party been the first to view [the films],” 447 U. S., at 657, n. 9, and in emphasizing that “[e]ven 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.” Id., at 657 (emphasis added). Nor does Justice Blackmun’s dissent in Walter necessarily support today’s holding, for it emphasized that the opened con*132tainers turned over to the Government agents “clearly revealed the nature of their contents,” id., at 663; see id., at 665, and the facts of this case, at least as viewed by the Court, do not support such a conclusion.
Today’s decision also is not supported by the majority’s reference to cases involving the transmission of previously private information to the police by a third party who has been made privy to that information. Ante, at 117-118. The police may, to be sure, use confidences revealed to them by a third party to establish probable cause or for other purposes, and the third party may testify about those confidences at trial without violating the Fourth Amendment. But we have never intimated until now that an individual who reveals that he stores contraband in a particular container or location to an acquaintance who later betrays his confidence has no expectation of privacy in that container or location and that the police may thus search it without a warrant.
That, I believe, is the effect of the Court’s opinion. If a private party breaks into a locked suitcase, a locked car, or even a locked house, observes incriminating information, returns the object of his search to its prior locked condition, and then reports his findings to the police, the majority apparently would allow the police to duplicate the prior search on the ground that the private search vitiated the owner’s expectation of privacy. As J ustice Stevens has previously observed, this conclusion cannot rest on the proposition that the owner no longer has a subjective expectation of privacy since a person’s expectation of privacy cannot be altered by subsequent events of which he was unaware. Walter v. United States, supra, at 659, n. 12.
The majority now ignores an individual’s subjective expectations and suggests that “[t]he reasonableness of an official invasion of a citizen’s privacy must be appraised on the basis of the facts as they existed at the time that invasion occurred.” Ante, at 115. On that view, however, the reasonableness of a particular individual’s remaining expectation of privacy should turn entirely on whether the private *133search left incriminating evidence or contraband in plain view. Cf. Walter v. United States, supra, at 663, 665 (Blackmun, J., dissenting). If the evidence or contraband is not in plain view and not in a container that clearly announces its contents at the end of a private search, the government’s subsequent examination of the previously searched object necessarily constitutes an independent, governmental search that infringes Fourth Amendment privacy interests. 447 U. S., at 662 (White, J., concurring in part and concurring in judgment).
The majority opinion is particularly troubling when one considers its logical implications. I would be hard-pressed to distinguish this case, which involves a private search, from (1) one in which the private party’s knowledge, later communicated to the government, that a particular container concealed contraband and nothing else arose from his presence at the time the container was sealed; (2) one in which the private party learned that a container concealed contraband and nothing else when it was previously opened in his presence; or (3) one in which the private party knew to a certainty that a container concealed contraband and nothing else as a result of conversations with its owner. In each of these cases, the approach adopted by the Court today would seem to suggest that the owner of the container has no legitimate expectation of privacy in its contents and that government agents opening that container without a warrant on the strength of information provided by the private party would not violate the Fourth Amendment.
Because I cannot accept the majority’s novel extension of the private-search doctrine and its implications for the entire concept of legitimate expectations of privacy, I concur only in Part III of its opinion and in the judgment.