with whom Justice Brennan and Justice Marshall join, concurring in part and dissenting in part.
The beeper is a species of radio transmitter. Mounted inside a container, it has much in common with a microphone mounted on a person. It reveals the location of the item to which it is attached — the functional equivalent of a radio transmission saying “Now I am at-.”
The threshold question in this case is whether the beeper invaded any interest protected by the Fourth Amendment. As we wrote earlier this Term, the Fourth Amendment
“protects two kinds of expectations, one involving ‘searches,’ the other ‘seizures.’ A ‘search’ occurs when an expectation of privacy that society is prepared to consider reasonable is infringed. A ‘seizure’ of property occurs when there is some meaningful interference with an individual’s possessory interests in that property.” United States v. Jacobsen, 466 U. S. 109, 113 (1984) (footnotes omitted).
In my opinion the surreptitious use of a radio transmitter— whether it contains a microphone or merely a signalling device — on an individual’s personal property is both a seizure and a search within the meaning of the Fourth Amendment. Part III of the opinion of the Court correctly concludes that when beeper surveillance reveals the location of property that has been concealed from public view, it constitutes a “search” within the meaning of the Fourth Amendment. I join Part III on that understanding. However, I find it necessary to write separately because I believe the Fourth Amendment’s reach is somewhat broader than that which is explicitly acknowledged by the Court, and in particular *729because my understanding of the Fourth Amendment, as well as my understanding of the issues that have been framed for us by the parties to this case, leads me to a different result than that reached by the Court.
HH
The attachment of the beeper, in my judgment, constituted a “seizure.”1 The owner of property, of course, has a right to exclude from it all the world, including the Government, and a concomitant right to use it exclusively for his own purposes. When the Government attaches an electronic monitoring device to that property, it infringes that exclusionary right; in a fundamental sense it has converted the property to its own use. Surely such an invasion is an “interference” with possessory rights; the right to exclude, which attached as soon as the can respondents purchased was delivered, had been infringed.2 That interference is also “meaningful”; the character of the property is profoundly different when infected "with an electronic bug than when it is entirely germ free.
The impact on possessory rights of this type of governmental conduct is illustrated by Silverman v. United States, 365 U. S. 505 (1961). There the Court held that the attachment of a microphone to the heating duct of an apartment building in order to eavesdrop on conversations in a nearby apartment implicated the Fourth Amendment:
*730“[T]he officers overheard the petitioners’ conversations only by usurping part of the petitioners’ house or office— a heating system which was an integral part of the premises occupied by the petitioners, a usurpation that was effected without their knowledge and without their consent. In these circumstances we need not pause to consider whether or not there was a technical trespass under the local property law relating to party walls. Inherent Fourth Amendment rights are not inevitably measurable in terms of ancient niceties of tort or real property law.” Id., at 511 (footnote omitted).
Here too, by attaching a monitoring device to respondents’ property, the agents usurped a part of a citizen’s property— in this case a part of respondents’ exclusionary rights in their tangible personal property. By attaching the beeper and using the container to conceal it, the Government in the most fundamental sense was asserting “dominion and control” over the property — the power to use the property for its own purposes. And “asserting] dominion and control” is a “seizure” in the most basic sense of the term. See Jacobsen, 466 U. S., at 120.3
II
The Court has developed a relatively straightforward test for determining what expectations of privacy are protected by the Fourth Amendment with respect to the possession of personal property. If personal property is in the plain view of the public, the possession of the property is in no sense “private” and hence is unprotected: “What a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection.” Katz v. *731United States, 389 U. S. 347, 351 (1967).4 When a person’s property is concealed from public view, however, then the fact of his possession is private and the subject of Fourth Amendment protection.
“One point on which the Court was in virtually unanimous agreement in Robbins [v. California, 453 U. S. 420 (1981)] was that a constitutional distinction between ‘worthy’ and ‘unworthy’ containers would be improper. . . . [T]he central purpose of the Fourth Amendment forecloses such a distinction. For just as the most frail cottage in the kingdom is absolutely entitled to the same guarantees of privacy as the most majestic mansion, so also may a traveler who carries a toothbrush and a few articles of clothing in a paper bag or knotted scarf claim an equal right to conceal his possessions from official inspection as the sophisticated executive with the locked attaché case.” United States v. Ross, 456 U. S. 798, 822 (1982).
Thus, “the Fourth Amendment provides protection to the owner of every container that conceals its contents from plain view.” Id., at 822-823.5
United States v. Knotts, 460 U. S. 276 (1983), illustrates this approach. There, agents watched as a container of chloroform in which they had placed a beeper was delivered to Knotts’ codefendant and placed in his car. They then used the beeper to track the car’s movements on a single trip *732through a public place. Used in this way the beeper did not disclose that the codefendant was in possession of the property; the agents already knew that. It revealed only the route of a trip through areas open to the public, something that was hardly concealed from public view. The Court held: “A person traveling in an automobile on public throroughfares has no reasonable expectation of privacy in his movements from one place to another.” Id., at 281.6
It is certainly true that a homeowner has a reasonable expectation of privacy in the contents of his home, including items owned by others. Alderman v. United States, 394 U. S. 165, 176-177 (1969).7 But focusing on the interest of *733the homeowner should not obscure the independent interest of those in possession of property that is monitored through the use of a beeper while the property is in a home or in any other location in which it is concealed from public view.
In this case, the beeper enabled the agents to learn facts that were not exposed to public view. In Knotts the agents already saw the codefendant take possession of chloroform, and therefore the beeper accomplished no more than following the codefendant without the aid of the beeper would have. Here, once the container went into Karo’s house, the agents thereafter learned who had the container and where it was only through use of the beeper. The beeper alone told them when the container was taken into private residences and storage areas, and when it was transported from one place to another.
The Court recognizes that concealment of personal property from public view gives rise to Fourth Amendment protection when it writes: “Indiscriminate monitoring of property that has been withdrawn from public view would present far too serious a threat to privacy interests in the home to escape entirely some sort of Fourth Amendment oversight.” Ante, at 716 (footnote omitted). This protection is not limited to times when the beeper was in a home.8 *734The beeper also revealed when the can of ether had been moved. When a person drives down a public thoroughfare in a car with a can of ether concealed in the trunk, he is not exposing to public view the fact that he is in possession of a can of ether; the can is still “withdrawn from public view” and hence its location is entitled to constitutional protection. If a footlocker, see United States v. Chadwick, 433 U. S. 1 (1977), or even a “knotted scarf,” entitles the owner of property to conceal its location from official inspection, then surely placing it in a car suffices as well.9 In this case it was only the beeper that enabled the agents to discover where the can was once it had been concealed in Karo’s house. At no point thereafter did the District Court find or does the Government contend that the location of the can was exposed to public view; the agents did not know when it was moved and hence would not have been able to follow its route without the aid of the beeper. Moreover, here the agents could not have employed visual surveillance to determine when the can was moved for fear of detection. Ante, at 714. Because the beeper enabled them to learn the location of personal *735property not exposed to public view, it invaded an interest embraced in the Fourth Amendment’s conception of a “search.”
This “search” began at the moment Karo brought the can into his house and hence concealed it from public view. As a general matter, the private citizen is entitled to assume, and in fact does assume, that his possessions are not infected with concealed electronic devices. The concealment of such items on personal property significantly compromises the owner’s interest in privacy, by making it impossible to conceal that item’s possession and location from the Government, despite the fact that the Fourth Amendment protects the privacy interest in the location of personal property not exposed to public view. I find little comfort in the Court’s notion that no invasion of privacy occurs until a listener obtains some significant information by use of the device. Ante, at 712. The expectation of privacy should be measured from the standpoint of the citizen whose privacy is at stake, not of the Government. It is compromised the moment the invasion occurs. A bathtub is a less private area when the plumber is present even if his back is turned.10
The agents did not know who was in possession of the property or where it was once it entered Karo’s house. From that moment on it was concealed from view. Because the beeper enabled the agents to learn the location of property otherwise concealed from public view, it infringed a privacy interest protected by the Fourth Amendment.11
*736III
The impact of beeper surveillance upon interests protected by the Fourth Amendment leads me to what I regard as the perfectly sensible conclusion that absent exigent circumstances Government agents have a constitutional duty to obtain a warrant before they install an electronic device on a private citizen’s property.
Because the Government does not challenge the conclusion that the warrant purporting to authorize the installation of the beeper was obtained improperly, I would affirm the judgment of the Court of Appeals. I would not engage in a de novo examination of the record in an effort to determine whether there is sufficient information independent of that obtained by means of the beeper to support the issuance of the warrant to search the Taos house. That question was not raised in the petition for certiorari and has not been briefed by the parties.12 Surely this is an inquiry that should be made in the first instance by the trial court after the parties have had an opportunity to argue the issue.
Accordingly, I respectfully dissent.
The seizure issue was not decided in United States v. Knotts, 460 U. S. 276 (1983); there Knotts did not challenge the installation of the beeper or its impact on his possessory rights. See id., at 279, n.; see also id., at 286 (Brennan, J., concurring in judgment); id., at 288 (Stevens, J., concurring in judgment).
It makes no difference in this case that when the beeper was initially attached, the can had not yet been delivered to respondents. Once the delivery had been effected, the container was respondents’ property from which they had the right to exclude all the world. It was at that point that the infringement of this constitutionally protected interest began.
It follows that those with possessory interests in the can to which the beeper was attached have standing to challenge the seizure and that the “seizure” tainted all of the beeper surveillance in this case.
See Smith v. Maryland, 442 U. S. 735, 744-746 (1979); United States v. Miller, 425 U. S. 435, 442 (1976); United States v. Dionisio, 410 U. S. 1, 14 (1973).
See United States v. Jacobsen, 466 U. S. 109, 129 (1984) (White, J., concurring in part and concurring in judgment); Illinois v. Andreas, 463 U. S. 765, 768, 771 (1983); Robbins v. California, 453 U. S. 420, 426-427 (1981) (plurality opinion); Arkansas v. Sanders, 442 U. S. 753, 764-765 (1979); United States v. Chadwick, 433 U. S. 1, 13, and n. 8 (1977). See also Jacobsen, 466 U. S., at 120, n. 17.
The Court was careful to note that the beeper had not revealed anything that was not exposed to public view: “A police car following Petschen at a distance throughout his journey could have observed him leaving the public highway and arriving at the cabin owned by respondent, with the drum of chloroform still in the car. This fact, along with others, was used by the government in obtaining a search warrant which led to the discovery of the clandestine drug laboratory. But there is no indication that the beeper was used in any way to reveal information as to the movement of the drum within the cabin, or in any way that would not have been visible to the naked eye from outside the cabin.” 460 U. S., at 285. See also ante, at 713-714.
I agree with the Court’s response, ante, at 716-717, n. 4, to Justice O’Connor’s position, which I take to be that when the homeowner has no power to check the inside of a container for the presence of a beeper, he must always assume the risk that his guests will carry with them items that are being electronically monitored. Moreover, I do not believe that electronic surveillance has become or ever should be permitted to become so pervasive that homeowners must expect that containers brought into their homes are infested with electronic bugs. While Rawlings v. Kentucky, 448 U. S. 98 (1980), establishes that one may not have a reasonable expectation of privacy in the contents of a container in the possession of another, the search in that case did not occur in Rawlings’ home, see id., at 100-101, and hence sheds no light on the Fourth Amendment rights of the homeowner. Those rights are defined in Alderman, where we concluded that the homeowner may object to police conduct that reveals what has gone on in his home irrespective of whether he has any expectation of privacy in the effects that have been searched and seized: “If the police make an unwarranted search of a house and seize tangible property belonging to *733third parties — even a transcript of a third-party conversation — the homeowner may object to its use against him, not because he had any interest in the seized items as ‘effects’ protected by the Fourth Amendment, but because they were the fruits of an unauthorized search of his house, which is itself expressly protected by the Fourth Amendment.” 394 U. S., at 176-177 (footnote omitted).
The Court seems to acknowledge as much, since it indicates that the location of property can be private even when not in a home. See ante, at 720, n. 6. And even if it is assumed that a beeper infringes privacy interests only with respect to the location of items concealed within a home, the “search” that the Court concludes began when the can containing the beeper went into Karo’s home did not end when it left the home. When the agents monitored the beeper at a later point and learned that the can was no longer in the home, the invasion of the privacy of Karo’s home continued; by learning that the can was no longer in the home the monitoring *734told the agents something they otherwise would not have known about what was in Karo’s home. If monitoring of a beeper constitutes a search because it “establishes that the article remains on the premises,” ante, at 715, it is no less a search when it establishes that the article has left the premises. For this reason, the Court’s holding in Part IV of its opinion that any violation of respondents’ privacy rights before the can left the second warehouse did not taint its later monitoring is flawed. The later monitoring necessarily told police that the container had left areas the Court considers protected, and therefore itself violated privacy rights.
It follows that I believe Justice O’Connor’s criteria are sufficient to accord an accused standing to challenge beeper surveillance — if that person had the power to prevent visual surveillance of the container and hence a reasonable expectation that the location of the property would remain private, he can challenge beeper surveillance of the container. Ante, at 727-728. Since it is the location of the property that is concealed from public view and hence private, those who have concealed the items are the persons whose privacy has been invaded, if the property was concealed in a place where they could reasonably expect its location would remain private. See United States v. Salvucci, 448 U. S. 83, 91-93 (1980).
The Court states: “The mere transfer to Karo of a can containing an unmonitored beeper infringed no privacy interest.” Ante, at 712. Presumably the Court would also conclude that no privacy interest would be infringed by the entrance of a blindfolded plumber.
It follows that I disagree with the Court’s conclusion that the monitoring of the beeper that revealed it was in the second warehouse did not constitute a search. Ante, at 720-721. The property was concealed from public view; its location was a secret and hence by revealing its location the beeper infringed an expectation of privacy. Without the beeper, the agents would have never found the warehouse, and hence would have never set up visual surveillance of the locker containing the can of ether.
The questions presented in the petition for certiorari are:
“1. Whether warrantless installation of a beeper inside a container of chemicals with the consent of the original owner violates the Fourth Amendment rights of a suspect in a drug manufacturing scheme to whom the container is subsequently transferred.
“2. Whether the warrantless monitoring of signals from a beeper installed inside a container of chemicals that law enforcement authorities reasonably believe will be used to manufacture illegal drugs violates the Fourth Amendment when the monitoring occurs while the beeper is located within a home or other ‘private’ area (such as a commercial storage locker).” Pet. for Cert. I.
I fail to see how the discussion in Part IV of the opinion of the Court addresses either of these questions. To the contrary, it appears that the Court has concluded that the Court of Appeals answered both of these questions correctly even as it reverses the judgment.