Justice White
announced the judgment of the Court and delivered an opinion, in which Justice Marshall, Justice Powell, and Justice Stevens joined.
We are required in this case to determine whether the Court of Appeal of Florida, Third District, properly applied the precepts of the Fourth Amendment in holding that respondent Royer was being illegally detained at the time of his purported consent to a search of his luggage.
On January 3, 1978, Royer was observed at Miami International Airport by two plainclothes detectives of the Dade County, Fla., Public Safety Department assigned to the county’s Organized Crime Bureau, Narcotics Investigation Section. Detectives Johnson and Magdalena believed that Royer’s appearance, mannerisms, luggage, and actions fit the so-called “drug courier profile.” Royer, apparently unaware of the attention he had attracted, purchased a one-way ticket to New York City and checked his two suitcases, placing on each suitcase an identification tag bearing the name “Holt” and the destination “La Guardia.” As Royer made his way to the concourse which led to the airline boarding area, the two detectives approached him, identified themselves as policemen working out of the sheriff’s office, and asked if Royer had a “moment” to speak with them; Royer said “Yes.”
Upon request, but without oral consent, Royer produced for the detectives his airline ticket and his driver’s license. The airline ticket, like the baggage identification tags, bore the name “Holt,” while the driver’s license carried respondent’s correct name, “Royer.” When the detectives asked about the discrepancy, Royer explained that a friend had made the reservation in the name of “Holt.” Royer became noticeably more nervous during this conversation, whereupon the detectives informed Royer that they were in fact narcotics investigators and that they had reason to suspect him of transporting narcotics.
The detectives did not return his airline ticket and identification but asked Royer to accompany them to a room, approximately 40 feet away, adjacent to the concourse. Royer said nothing in response but went with the officers as he had been asked to do. The room was later described by Detective Johnson as a “large storage closet,” located in the stewardesses’ lounge and containing a small desk and two chairs. Without Royer’s consent or agreement, Detective Johnson, using Royer’s baggage check stubs, retrieved the “Holt” luggage from the airline and brought it to the room where respondent and Detective Magdalena were waiting. Royer was asked if he would consent to a search of the suitcases. Without orally responding to this request, Royer produced a key and unlocked one of the suitcases, which one detective then opened without seeking further assent from Royer. Marihuana was found in that suitcase. According to Detective Johnson, Royer stated that he did not know the combination to the lock on the second suitcase. When asked if he objected to the detective opening the second suitcase, Royer said “[n]o, go ahead,” and did not object when the detective explained that the suitcase might have to be broken open. The suitcase was pried open by the officers and more marihuana was found. Royer was then told that he was under arrest. Approximately 15 minutes had elapsed from the time the detectives initially approached respondent until his arrest upon the discovery of the contraband.
Prior to his trial for felony possession of marihuana, Royer made a motion to suppress the evidence obtained in the search of the suitcases. The trial court found that Royer’s consent to the search was “freely and voluntarily given,” and that, regardless of the consent, the warrantless search was reasonable because “the officer doesn’t have the time to run out and get a search warrant because the plane is going to take off.” Following the denial of the motion to suppress, Royer changed his plea from “not guilty” to “nolo conten-dere,” specifically reserving the right to appeal the denial of the motion to suppress. Royer was convicted.
The District Court of Appeal, sitting en banc, reversed Royer’s conviction. The court held that Royer had been involuntarily confined within the small room without probable cause; that the involuntary detention had exceeded the limited restraint permitted by Terry v. Ohio, 392 U. S. 1 (1968), at the time his consent to the search was obtained; and that the consent to search was therefore invalid because tainted by the unlawful confinement.
Several factors led the court to conclude that respondent’s confinement was tantamount to arrest. Royer had “found himself in a small enclosed area being confronted by two police officers — a situation which presents an almost classic definition of imprisonment.” 389 So. 2d 1007, 1018 (1980). The detectives’ statement to Royer that he was suspected of transporting narcotics also bolstered the finding that Royer was “in custody” at the time the consent to search was given. Ibid. In addition, the detectives’ possession of Royer’s airline ticket and their retrieval and possession of his luggage made it clear, in the District Court of Appeal’s view, that Royer was not free to leave. Ibid.
At the suppression hearing Royer testified that he was under the impression that he was not free to leave the officers’ presence. The Florida District Court of Appeal found that this apprehension “was much more than a well-justified subjective belief,” for the State had conceded at oral argument before that court that “the officers would not have permitted Royer to leave the room even if he had erroneously thought he could.” Ibid. The nomenclature used to describe Royer’s confinement, the court found, was unimportant because under Dunaway v. New York, 442 U. S. 200 (1979), “a police confinement which . . . goes beyond the limited restraint of a Terry investigatory stop may be constitutionally justified only by probable cause.” 389 So. 2d, at 1019 (footnote omitted). Detective Johnson, who conducted the search, had specifically stated at the suppression hearing that he did not have probable cause to arrest Royer until the suitcases were opened and their contents revealed. Ibid. In the absence of probable cause, the court concluded, Royer’s consent to search, given only after he had been unlawfully confined, was ineffective to justify the search. Ibid. Because there was no proof at all that a “break in the chain of illegality” had occurred, the court found that Royer’s consent was invalid as a matter of law. Id., at 1020. We granted the State’s petition for certiorari, 454 U. S. 1079 (1981), and now affirm.
II
Some preliminary observations are in order. First, it is unquestioned that without a warrant to search Royer’s luggage and in the absence of probable cause and exigent circumstances, the validity of the search depended on Royer’s purported consent. Neither is it disputed that where the validity of a search rests on consent, the State has the burden of proving that the necessary consent was obtained and that it was freely and voluntarily given, a burden that is not satisfied by showing a mere submission to a claim of lawful authority. Lo-Ji Sales, Inc. v. New York, 442 U. S. 319, 329 (1979); Schneckloth v. Bustamonte, 412 U. S. 218, 233-234 (1973); Bumper v. North Carolina, 391 U. S. 543, 548-549 (1968); Johnson v. United States, 333 U. S. 10, 13 (1948); Amos v. United States, 255 U. S. 313, 317 (1921).
Second, law enforcement officers do not violate the Fourth Amendment by merely approaching an individual on the street or in another public place, by asking him if he is willing to answer some questions, by putting questions to him if the person is willing to listen, or by offering in evidence in a criminal prosecution his voluntary answers to such questions. See Dunaway v. New York, supra, at 210, n. 12; Terry v. Ohio, 392 U. S., at 31, 32-33 (Harlan, J., concurring); id., at 34 (White, J., concurring). Nor would the fact that the officer identifies himself as a police officer, without more, convert the encounter into a seizure requiring some level of objective justification. United States v. Mendenhall, 446 U. S. 544, 555 (1980) (opinion of Stewart, J.). The person approached, however, need not answer any question put to him; indeed, he may decline to listen to the questions at all and may go on his way. Terry v. Ohio, 392 U. S., at 32-33 (Harlan, J., concurring); id., at 34 (White, J., concurring). He may not be detained even momentarily without reasonable, objective grounds for doing so; and his refusal to listen or answer does not, without more, furnish those grounds. United States v. Mendenhall, supra, at 556 (opinion of Stewart, J.). If there is no detention — no seizure within the meaning of the Fourth Amendment — then no constitutional rights have been infringed.
Third, it is also clear that not all seizures of the person must be justified by probable cause to arrest for a crime. Prior to Terry v. Ohio, supra, any restraint on the person amounting to a seizure for the purposes of the Fourth Amendment was invalid unless justified by probable cause. Dunaway v. New York, supra, at 207-209. Terry created a limited exception to this general rule: certain seizures are justifiable under the Fourth Amendment if there is articula-ble suspicion that a person has committed or is about to commit a crime. In that case, a stop and a frisk for weapons were found unexceptionable. Adams v. Williams, 407 U. S. 143 (1972), applied the same approach in the context of an informant’s report that an unnamed individual in a nearby vehicle was carrying narcotics and a gun. Although not expressly authorized in Terry, United States v. Brignoni-Ponce, 422 U. S. 873, 881-882 (1975), was unequivocal in saying that reasonable suspicion of criminal activity warrants a temporary seizure for the purpose of questioning limited to the purpose of the stop. In Brignoni-Ponce, that purpose was to verify or dispel the suspicion that the immigration laws were being violated, a governmental interest that was sufficient to warrant temporary detention for limited questioning. Royer does not suggest, nor do we, that a similar rationale would not warrant temporary detention for questioning on less than probable cause where the public interest involved is the suppression of illegal transactions in drugs or of any other serious crime.
Michigan v. Summers, 452 U. S. 692 (1981), involved another circumstance in which a temporary detention on less than probable cause satisfied the ultimate test of reasonableness under the Fourth Amendment. There the occupant of a house was detained while a search warrant for the house was being executed. We held that the warrant made the occupant sufficiently suspect to justify his temporary seizure. The “limited intrusio[n] on the personal security” of the person detained was justified “by such substantial law enforcement interests” that the seizure could be made on articulable suspicion not amounting to probable cause. Id., at 699.
Fourth, Terry and its progeny nevertheless created only limited exceptions to the general rule that seizures of the person require probable cause to arrest. Detentions may be “investigative” yet violative of the Fourth Amendment absent probable cause. In the name of investigating a person who is no more than suspected of criminal activity, the police may not carry out a full search of the person or of his automobile or other effects. Nor may the police seek to verify their suspicions by means that approach the conditions of arrest. Dunaway v. New York, swpra, made this clear. There, the suspect was taken to the police station from his home and, without being formally arrested, interrogated for an hour. The resulting incriminating statements were held inadmissible: reasonable suspicion of crime is insufficient to justify custodial interrogation even though the interrogation is investigative. Id., at 211-212. Brown v. Illinois, 422 U. S. 590 (1975), and Davis v. Mississippi, 394 U. S. 721 (1969), are to the same effect.
The Fourth Amendment’s prohibition against unreasonable searches and seizures has always been interpreted to prevent a search that is not limited to the particularly described “place to be searched, and the persons or things to be seized,” U. S. Const., Arndt. 4, even if the search is made pursuant to a warrant and based upon probable cause. The Amendment’s protection is not diluted in those situations where it has been determined that legitimate law enforcement interests justify a warrantless search: the search must be limited in scope to that which is justifed by the particular purposes served by the exception. For example, a warrantless search is permissible incident to a lawful arrest because of legitimate concerns for the safety of the officer and to prevent the destruction of evidence by the arrestee. E. g., Chimel v. California, 395 U. S. 752, 763 (1969). Nevertheless, such a search is limited to the person of the arrestee and the area immediately within his control. Id., at 762. Terry v. Ohio, supra, also embodies this principle: “The scope of the search must be ‘strictly tied to and justified by’ the circumstances which rendered its initiation permissible.” 392 U. S., at 19, quoting Warden v. Hayden, 387 U. S. 294, 310 (1967) (For-tas, J., concurring). The reasonableness requirement of the Fourth Amendment requires no less when the police action is a seizure permitted on less than probable cause because of legitimate law enforcement interests. The scope of the detention must be carefully tailored to its underlying justification.
The predicate permitting seizures on suspicion short of probable cause is that law enforcement interests warrant a limited intrusion on the personal security of the suspect. The scope of the intrusion permitted will vary to some extent with the particular facts and circumstances of each case. This much, however, is clear: an investigative detention must be temporary and last no longer than is necessary to effectuate the purpose of the stop. Similarly, the investigative methods employed should be the least intrusive means reasonably available to verify or dispel the officer’s suspicion in a short period of time. See, e. g., United States v. Brignoni-Ponce, supra, at 881-882; Adams v. Williams, supra, at 146. It is the State’s burden to demonstrate that the seizure it seeks to justify on the basis of a reasonable suspicion was sufficiently limited in scope and duration to satisfy the conditions of an investigative seizure.
Fifth, Dunaway and Brown hold that statements given during a period of illegal detention are inadmissible even though voluntarily given if they are the product of the illegal detention and not the result of an independent act of free will. Dunaway v. New York, 442 U. S., at 218-219; Brown v. Illinois, supra, at 601-602. In this respect those cases reiterated one of the principal holdings of Wong Sun v. United States, 371 U. S. 471 (1963).
Sixth, if the events in this case amounted to no more than a permissible police encounter in a public place or a justifiable Terry-type detention, Royer’s consent, if voluntary, would have been effective to legalize the search of his two suitcases. Cf. United States v. Watson, 423 U. S. 411, 424-425 (1976). The Florida District Court of Appeal in the case before us, however, concluded not only that Royer had been seized when he gave his consent to search his luggage but also that the bounds of an investigative stop had been exceeded. In its view the “confinement” in this case went beyond the limited restraint of a Terry investigative stop, and Royer’s consent was thus tainted by the illegality, a conclusion that required reversal in the absence of probable cause to arrest. The question before us is whether the record warrants that conclusion. We think that it does.
HH HH I — I
The State proffers three reasons for holding that when Royer consented to the search of his luggage, he was not being illegally detained. First, it is submitted that the entire encounter was consensual and hence Royer was not being held against his will at all. We find this submission untenable. Asking for and examining Royer’s ticket and his driver’s license were no doubt permissible in themselves, but when the officers identified themselves as narcotics agents, told Royer that he was suspected of transporting narcotics, and asked him to accompany them to the police room, while retaining his ticket and driver’s license and without indicating in any way that he was free to depart, Royer was effectively seized for the purposes of the Fourth Amendment. These circumstances surely amount to a show of official authority such that “a reasonable person would have believed that he was not free to leave.” United States v. Mendenhall, 446 U. S., at 554 (opinion of Stewart, J.) (footnote omitted).
Second, the State submits that if Royer was seized, there existed reasonable, articulable suspicion to justify a temporary detention and that the limits of a Terry-type stop were never exceeded. We agree with the State that when the officers discovered that Royer was traveling under an assumed name, this fact, and the facts already known to the officers— paying cash for a one-way ticket, the mode of checking the two bags, and Royer’s appearance and conduct in general— were adequate grounds for suspecting Royer of carrying drugs and for temporarily detaining him and his luggage while they attempted to verify or dispel their suspicions in a manner that did not exceed the limits of an investigative detention. We also agree that had Royer voluntarily consented to the search of his luggage while he was justifiably being detained on reasonable suspicion, the products of the search would be admissible against him. We have concluded, however, that at the time Royer produced the key to his suitcase, the detention to which he was then subjected was a more serious intrusion on his personal liberty than is allowable on mere suspicion of criminal activity.
By the time Royer was informed that the officers wished to examine his luggage, he had identified himself when approached by the officers and had attempted to explain the discrepancy between the name shown on his identification and the name under which he had purchased his ticket and identified his luggage. The officers were not satisfied, for they informed him they were narcotics agents and had reason to believe that he was carrying illegal drugs. They requested him to accompany them to the police room. Royer went with them. He found himself in a small room — a large closet — equipped with a desk and two chairs. He was alone with two police officers who again told him that they thought he was carrying narcotics. He also found that the officers, without his consent, had retrieved his checked luggage from the airline. What had begun as a consensual inquiry in a public place had escalated into an investigatory procedure in a police interrogation room, where the police, unsatisfied with previous explanations, sought to confirm their suspicions. The officers had Royer’s ticket, they had his identification, and they had seized his luggage. Royer was never informed that he was free to board his plane if he so chose, and he reasonably believed that he was being detained. At least as of that moment, any consensual aspects of the encounter had evaporated, and we cannot fault the Florida District Court of Appeal for concluding that Terry v. Ohio and the cases following it did not justify the restraint to which Royer was then subjected. As a practical matter, Royer was under arrest. Consistent with this conclusion, the State conceded in the Florida courts that Royer would not have been free to leave the interrogation room had he asked to do so. Furthermore, the State’s brief in this Court interprets the testimony of the officers at the suppression hearing as indicating that had Royer refused to consent to a search of his luggage, the officers would have held the luggage and sought a warrant to authorize the search. Brief for Petitioner 6.
We also think that the officers’ conduct was more intrusive than necessary to effectuate an investigative detention otherwise authorized by the Terry line of cases. First, by returning his ticket and driver’s license, and informing him that he was free to go if he so desired, the officers might have obviated any claim that the encounter was anything but a consensual matter from start to finish. Second, there are undoubtedly reasons of safety and security that would justify moving a suspect from one location to another during an investigatory detention, such as from an airport concourse to a more private area. Cf. Pennsylvania v. Mimms, 434 U. S. 106, 109-111 (1977) (per curiam). There is no indication in this case that such reasons prompted the officers to transfer the site of the encounter from the concourse to the interrogation room. It appears, rather, that the primary interest of the officers was not in having an extended conversation with Royer but in the contents of his luggage, a matter which the officers did not pursue orally with Royer until after the encounter was relocated to the police room. The record does not reflect any facts which would support a finding that the legitimate law enforcement purposes which justified the detention in the first instance were furthered by removing Royer to the police room prior to the officers’ attempt to gain his consent to a search of his luggage. As we have noted, had Royer consented to a search on the spot, the search could have been conducted with Royer present in the area where the bags were retrieved by Detective Johnson and any evidence recovered would have been admissible against him. If the search proved negative, Royer would have been free to go much earlier and with less likelihood of missing his flight, which in itself can be a very serious matter in a variety of circumstances.
Third, the State has not touched on the question whether it would have been feasible to investigate the contents of Royer’s bags in a more expeditious way. The courts are not strangers to the use of trained dogs to detect the presence of controlled substances in luggage. There is no indication here that this means was not feasible and available. If it had been used, Royer and his luggage could have been momentarily detained while this investigative procedure was carried out. Indeed, it may be that no detention at all would have been necessary. A negative result would have freed Royer in short order; a positive result would have resulted in his justifiable arrest on probable cause.
We do not suggest that there is a litmus-paper test for distinguishing a consensual encounter from a seizure or for determining when a seizure exceeds the bounds of an investigative stop. Even in the discrete category of airport encounters, there will be endless variations in the facts and circumstances, so much variation that it is unlikely that the courts can reduce to a sentence or a paragraph a rule that will provide unarguable answers to the question whether there has been an unreasonable search or seizure in violation of the Fourth Amendment. Nevertheless, we must render judgment, and we think that the Florida District Court of Appeal cannot be faulted in concluding that the limits of a Terry-stop had been exceeded.
IV
The State’s third and final argument is that Royer was not being illegally held when he gave his consent because there was probable cause to arrest him at that time. Detective Johnson testified at the suppression hearing and the Florida District Court of Appeal held that there was no probable cause to arrest until Royer’s bags were opened, but the fact that the officers did not believe there was probable cause and proceeded on a consensual or Terry-stop rationale would not foreclose the State from justifying Royer’s custody by proving probable cause and hence removing any barrier to relying on Royer’s consent to search. Peters v. New York, decided with Sibron v. New York, 392 U. S. 40, 66-67 (1968). We agree with the Florida District Court of Appeal, however, that probable cause to arrest Royer did not exist at the time he consented to the search of his luggage. The facts are that a nervous young man with two American Tourister bags paid cash for an airline ticket to a “target city.” These facts led to inquiry, which in turn revealed that the ticket had been bought under an assumed name. The proffered explanation did not satisfy the officers. We cannot agree with the State, if this is its position, that every nervous young man paying cash for a ticket to New York City under an assumed name and carrying two heavy American Tourister bags may be arrested and held to answer for a serious felony charge.
V
Because we affirm the Florida District Court of Appeal’s conclusion that Royer was being illegally detained when he consented to the search of his luggage, we agree that the consent was tainted by the illegality and was ineffective to justify the search. The judgment of the Florida District Court of Appeal is accordingly
Affirmed.
The facts set forth in this opinion are taken from the en banc decision of the Florida District Court of Appeal, Third District, 389 So. 2d 1007, 1015-1018 (1980), and from the transcript of the hearing on the motion to suppress contained in the joint appendix. App. 11A-116A.
The “drug courier profile” is an abstract of characteristics found to be typical of persons transporting illegal drugs. In Royer’s ease, the detectives attention was attracted by the following facts which were considered to be within the profile: (a) Royer was carrying American Tourister luggage, which appeared to be heavy, (b) he was young, apparently between 25-35, (c) he was casually dressed, (d) he appeared pale and nervous, looking around at other people, (e) he paid for his ticket in cash with a large number of bills, and (f) rather than completing the airline identification tag to be attached to checked baggage, which had space for a name, address, and telephone number, he wrote only a name and the destination. 389 So. 2d, at 1016; App. 27A-40A.
Fla. Stat. §893.13(l)(a)(2) (1975).
App. 114A-116A.
Under Florida law, a plea of nolo contendere is equivalent to a plea of guilty.
On appeal, a panel of the District Court of Appeal of Florida found that viewing the totality of the circumstances, the finding of consent by the trial court was supported by clear and convincing evidence. 389 So. 2d 1007 (1979). The panel decision was vacated and rehearing en banc granted. Id., at 1015 (1980). It is the decision of the en banc court that is reviewed here.
The Florida court was also of the opinion that “a mere similarity with the contents of the drug courier profile is insufficient even to constitute the articulable suspicion required to justify” the stop authorized by Terry v. Ohio. It went on to hold that even if it followed a contrary rule, or even if articulable suspicion occurred at some point prior to Royer’s consent to search, the facts did not amount to probable cause that would justify the restraint imposed on Royer. 389 So. 2d, at 1019. As will become clear, we disagree on the reasonable-suspicion issue but do concur that probable cause to arrest was lacking.
In its brief and at oral argument before this Court, the State contests whether this concession was ever made. We have no basis to question the statement of the Florida court.
Our decision here is consistent with the Court’s judgment in United States v. Mendenhall, 446 U. S. 544 (1980). In Mendenhall, the respondent was walking along an airport concourse when she was approached by two federal Drug Enforcement Agency (DEA) officers. As in the present case, the officers asked for Mendenhall’s airline ticket and some identification; the names on the ticket and identification did not match. When one of the agents specifically identified himself as attached to the DEA, Men-denhall became visibly shaken and nervous. Id., at 548.
After returning the ticket and identification, one officer asked Menden-hall if she would accompany him to the DEA airport office, 50 feet away, for further questions. Once in the office, Mendenhall was asked to consent to a search of her person and her handbag; she was advised of her right to decline. Ibid. In a private room following further assurance from Men-denhall that she consented to the search, a policewoman began the search of Mendenhall’s person by requesting that Mendenhall disrobe. As she began to undress, Mendenhall removed two concealed packages that appeared to contain heroin and handed them to the policewoman. Id., at 549. The Court of Appeals determined that the initial “stop” of Menden-hall was unlawful because not based upon a reasonable suspicion of criminal activity. In the alternative, the court found that even if the initial stop was permissible, the officer’s request that Mendenhall accompany him to the DEA office constituted an arrest without probable cause.
This Court reversed. Two Justices were of the view that the entire encounter was consensual and that no seizure had taken place. Three other Justices assumed that there had been a seizure but would have held that there was reasonable suspicion to warrant it; hence a voluntary consent to search was a valid basis for the search. Thus, the five Justices voting to reverse appeared to agree that Mendenhall was not being illegally detained when she consented to be searched. The four dissenting Justices also assumed that there had been a detention but were of the view that reasonable grounds for suspecting Mendenhall did not exist and concluded that Mendenhall was thus being illegally detained at the time of her consent.
The case before us differs in important respects. Here, Royer’s ticket and identification remained in the possession of the officers throughout the encounter; the officers also seized and had possession of his luggage. As a practical matter, Royer could not leave the airport without them. In Mendenhall, no luggage was involved, the ticket and identification were immediately returned, and the officers were careful to advise that the suspect could decline to be searched. Here, the officers had seized Royer’s luggage and made no effort to advise him that he need not consent to the search.
Courts of Appeals are in disagreement as to whether using a dog to detect drugs in luggage is a search, but no Court of Appeals has held that more than an articulable suspicion is necessary to justify this kind of a war-rantless search if indeed it is a search. See, e. g., United States v. Sullivan, 625 F. 2d 9, 13 (CA4 1980) (no search), cert. denied, 450 U. S. 923 (1981); United States v. Burns, 624 F. 2d 95, 101 (CA10 1980) (same); United States v. Beale, 674 F. 2d 1327, 1335 (CA9 1982) (sniff is an intrusion requiring reasonable suspicion), cert, pending, No. 82-674. Furthermore, the law of the Circuit from which this case comes was and is that “use of [drug-detecting canines] constitute^] neither a search nor a seizure under the Fourth Amendment.” United States v. Goldstein, 635 F. 2d 356, 361 (CA5), cert. denied, 452 U. S. 962 (1981). See United States v. Viera, 644 F. 2d 509, 510 (CA5), cert. denied, 454 U. S. 867 (1981). Decisions of the United States Court of Appeals for the Fifth Circuit rendered prior to September 30, 1981, are binding precedent on the United States Court of Appeals for the Eleventh Circuit. Bonner v. City of Prichard, 661 F. 2d 1206, 1207 (CA11 1981).
In any event, we hold here that the officers had reasonable suspicion to believe that Royer’s luggage contained drugs, and we assume that the use of dogs in the investigation would not have entailed any prolonged detention of either Royer or his luggage which may involve other Fourth Amendment concerns. In United States v. Beale, supra, for example, after briefly questioning two suspects who had checked baggage for a flight from the Fort Lauderdale, Fla., airport, the officers proceeded to the baggage area where a trained dog alerted to one of the checked bags. Meanwhile, the suspects had boarded their plane for California, where their bags were again sniffed by a trained dog and they were arrested. The Court of Appeals for the Ninth Circuit vacated a judgment convicting the suspects on the ground that articulable suspicion was necessary to justify the use of a trained dog to sniff luggage and that the existence or not of that requirement should have been determined in the District Court. 674 F. 2d, at 1335. In the case before us, the officers, with founded suspicion, could have detained Royer for the brief period during which Florida authorities at busy airports seem able to carry out the dog-sniffing procedure.