Almost a century ago, Justice Gray eloquently captured the essence of the Fourth Amendment’s guarantees when he noted that “[n]o right ... is more carefully guarded by the common law, than the right of every individual to the possession and control of his own person, free from all restraint or interference of others, unless by clear and unquestionable authority of law.” 1 Courts accordingly have proceeded with caution when determining whether the interaction of a law enforcement official with the freedoms of an individual offends the Fourth Amendment. With increasing recurrence, we have considered the delicate balance which must be struck between the interest of the public in terminating narcotics smuggling and the individual’s right to live unburdened by unreasonable intrusions on his privacy as we are called upon to assess the constitutionality of a warrantless “investigatory stop” of domestic air passengers by Drug Enforcement Administration agents struggling to stem the flood of dangerous drugs.
*339Today we are asked once again to determine whether a warrantless airport stop and search initiated to apprehend a narcotics courier falls within constitutionally permissible bounds. Nelly Pilar Ramirez-Ci-fuentes was stopped and briefly questioned by Drug Enforcement Administration Agent Alfredo Iglesias at LaGuardia Airport as part of the Drug Enforcement Administration’s program to intercept illegal drugs. The subsequent search of her black shoulder bag revealed 540 grams of 93 percent pure cocaine. After a hearing, Judge Platt denied her motion to suppress the cocaine and certain statements she had made to Agent Iglesias. Ms. Ramirez-Ci-fuentes then entered a plea of guilty2 to possessing cocaine with intent to distribute it in violation of 21 U.S.C. § 841(a)(1).3 She now would have us determine that the district court improperly denied her motion to suppress the evidence because the cocaine was taken from her as a result of an unconstitutional investigatory stop and search in the course of which the seizure occurred. Because we find Judge Platt correctly denied the suppression motion, we affirm the judgment of conviction.
I
At the suppression hearing before Judge Platt, the familiar scenario of surveillance and encounter unfolded. On the evening of June 16, 1981, Drug Enforcement Administration (“DEA”) Agents Alfredo Iglesias and Jesse Meekins were stationed at La-Guardia Airport in New York as part of the DEA’s endeavors to monitor passengers on flights from certain “source cities” to control the flow of illegal drugs. Agents Igle-sias, who had six years’ experience with the DEA, and Meekins were awaiting the arrival of Eastern Airlines Flight 28, non-stop from Miami, a well-known source city, to New York to observe the passengers as they left the aircraft. They positioned themselves opposite Gates 33 and 34A in the Eastern Airlines Terminal so that they would have an unobstructed view of the faces and demeanor of the arriving passengers. At approximately 9:30 P.M., Flight 28 parked at the gate, and the passengers began to disembark and walk into the concourse. In the first group to emerge from the gate was appellant Ramirez-Cifuentes.
As Ms. Ramirez-Cifuentes entered the concourse that leads from the gate to the main terminal, she continually glanced about as if looking for someone or something. The agents’ attention was attracted to her because this was a limited access area in which it would be unusual for a passenger to be searching for someone meeting her, and, in addition, she was the only passenger Agent Iglesias could see engaging in such conduct. The agents followed her movements as she proceeded rapidly down the concourse, constantly turning her head to peer back toward the gate. As she walked quickly and vigorously, passing the normal flow of traffic, she looked once again in the direction of the agents, turned her head down, accelerated her gait, and pressed forward through the crowd. As the agents watched her progress, they noticed she was carrying two bags — a small aqua blue woman’s purse with a shoulder strap on her left shoulder as well as a round, soft black shoulder bag on her right. The black shoulder bag, which appeared to be new and filled to capacity, bore no identification tags and was clutched tightly to her body. At this point, Agent Iglesias, suspicious of Ms. Ramirez-Cifuentes’s conduct because it resembled the actions of narcotics traffickers he had apprehended during his years of experience, began to follow her down the concourse. Agent Meekins remained at the gate.
*340Walking very rapidly, almost running, to reach a place ten or fifteen feet behind her, Agent Iglesias continued to note her quick pace. He also observed that as she passed the security area, which was on the left side of the corridor, she took pains to stay far to the right. In addition, as she continued down the block-long corridor, an elderly woman approached her and asked, in Spanish, whether Ms. Ramirez-Cifuentes had been on the flight from Miami. Ignoring the question, she sped toward the end of the concourse, descended on an escalator, passed through the baggage area, claiming no luggage, and went out to the street. With Agent Iglesias still watching through the glass wall of the terminal, she turned, looked back into the building, and stared directly at him. She then joined a taxi line and repeatedly glanced about as if searching for someone.
After considering the import of his observations, Agent Iglesias left the building and approached Ms. Ramirez-Cifuentes on the taxi line. He immediately identified himself as a federal agent and displayed his badge. After ascertaining that her native tongue was Spanish, the agent, who is fluent in that language, repeated his statements in Spanish. He stated he would like to ask her a few questions and proceeded to do so as he walked with her in the line as it advanced. After determining Ms. Ramirez-Cifuentes had just arrived from Miami, he asked her to show him her airline ticket receipt. After rummaging through her bag, she produced a copy of a one-way ticket issued earlier that day by a travel agency, for cash, in the name of Rosa Gomez. Agent Iglesias examined the ticket and asked Ms. Ramirez-Cifuentes her name. She appeared startled by his inquiry and commenced looking about. Then, after some hesitation, she replied her name was Rosa Gomez. When identification was requested, she responded that she must have left it at home and added she did not even have her social security card.4
With this information now before him, Agent Iglesias asked if she would mind stepping out of line so they could continue the conversation unimpeded by the moving queue, and she agreed. Several steps away but still on the sidewalk, Ms. Ramirez-Ci-fuentes answered, in reply to the agent’s question, that she had no drugs. In response to his request to search the black shoulder bag, she said “sure” and opened a zipper on the bag. The agent, however, believing it the wiser course to conduct the search away from the flow of traffic, suggested they move to an area a few feet away inside the terminal in front of the Eastern Airlines baggage area. She then followed Agent Iglesias into the building. Once inside, he again requested permission to search the bag and she once more consented. The search revealed a gift-wrapped package, tightly secured with tape, but with no ribbons or card attached. When asked what was in the parcel, appellant asserted it contained only items of clothing purchased as a gift for a friend.
To Agent Iglesias, however, the answer did not ring true because the package felt too heavy for such contents. Moreover, during this conversation, his suspicions were further aroused by Ms. Ramirez-Cifuentes’s nervous demeanor. Indeed, at the suppression hearing he characterized her as “very nervous, extremely nervous. Her hands were shaking, her legs were shaking.” Accordingly, he told her he wished to unwrap the parcel. Contradicting her previous statement about the package, she, according to the agent’s testimony, stated: “Well, you have my permission but you can imagine what the person that gave me this box is going to think.” After attempting to dispel the confusion created by the conflicting explanations of the parcel through further inquiry, Agent Iglesias requested and appellant gave her consent to opening the package so long as the agent did not damage the gift-wrapping. After carefully unwrapping the box, he discovered approximately 540 grams of 93 percent pure cocaine.
*341Ms. Ramirez-Cifuentes was immediately arrested and given Miranda warnings. Indicating she understood, she related the events leading to the transportation of the package from Miami. In the main, she stated that she had been paid $500 to carry the parcel to New York.
Subsequently, she was charged with possession of cocaine with intent to distribute it in violation of 21 U.S.C. § 841(a)(1). She pleaded not guilty and requested suppression of certain statements as well as the cocaine on the grounds that the seizure of that evidence stemmed from violations of her Fourth Amendment rights. After a hearing, Judge Platt denied the motion to suppress. Ms. Ramirez-Cifuentes then entered a plea of guilty and was sentenced to three years imprisonment and a lifetime special parole term. This appeal followed.
II
Ms. Ramirez-Cifuentes urges us to conclude that Agent Iglesias had neither probable cause nor reasonable suspicion for approaching and questioning her as she waited on the taxi line. In addition, she contends her consent to the search of her black shoulder bag was not voluntary. Accordingly, appellant would have us hold that the 540 grams of cocaine discovered in the shoulder bag should have been suppressed. We cannot agree.
A.
In the course of the past few years, this Court has examined a number of challenges to the admissibility of evidence seized by DEA agents who have stopped suspected narcotics couriers arriving at LaGuardia Airport and secured their consent to conducting a search. The standards by which we assess a warrantless investigatory stop and related seizure are as clear, see United States v. Forero-Rincon, 626 F.2d 218, 221 (2d Cir. 1980), and as familiar as the circumstances and actions which culminate in these encounters.
While the Fourth Amendment prohibits only those searches and seizures which are not reasonable, see Delaware v. Prouse, 440 U.S. 648, 99 S.Ct. 1391, 59 L.Ed.2d 660 (1979), the seizure of a person or his effects is generally considered per se “unreasonable” unless a warrant has been obtained from a neutral magistrate upon a showing of probable cause. Katz v. United States, 389 U.S. 347, 357, 88 S.Ct. 507, 514, 19 L.Ed.2d 576 (1967). Recognizing that the exigencies of a particular situation would make it difficult if not impossible to procure a warrant, rare exceptions to this requirement have been spelled out such as the “automobile exception,” Chambers v. Maro-ney, 399 U.S. 42, 90 S.Ct. 1975, 26 L.Ed.2d 419 (1970), or border patrol stops based on reasonable suspicion. United States v. Brignoni-Ponce, 422 U.S. 873, 95 S.Ct. 2574, 45 L.Ed.2d 607 (1975).
The investigative stop in the case before us does not entail “the kind of intrusion involved in an arrest,” Dunaway v. New York, 442 U.S. 200, 208, 99 S.Ct. 2248, 2254, 60 L.Ed.2d 824 (1979), but rather fits within the narrowly circumscribed class of less intrusive stops first articulated in Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968). In Terry, supra, Chief Justice Warren, writing for the Court, set forth the now well-recognized precept that a law enforcement official, given appropriate circumstances, may approach an individual acting in a suspicious manner if the investigative stop is based on facts that generate a “reasonable suspicion” that the individual is engaged in criminal activity. The plethora of airport-search cases decided by this Court have relied on the teachings of Terry in evaluating whether, at the moment of the initial encounter between the officer and the suspected drug courier, on the basis of specific and articulable facts and the rational inferences to be drawn from them, the intrusion was based on reasonable suspicion. See, eg., United States v. Forero-Rincon, supra; United States v. Buenaventura-Ariza, 615 F.2d 29 (2d Cir. 1980); United States v. Vasquez, 612 F.2d 1338 (2d Cir. 1979), cert. denied, 447 U.S. 907, 100 S.Ct. 2991, 64 L.Ed.2d 857 (1980); United States v. Vasquez-Santiago, 602 F.2d 1069 (2d Cir. 1979), cert. denied, 447 U.S. 911, 100 S.Ct. *3422998, 64 L.Ed.2d 861 (1980); United States v. Price, 599 F.2d 494 (2d Cir. 1979); United States v. Rico, 594 F.2d 320 (2d Cir. 1979); United States v. Oates, 560 F.2d 45 (2d Cir. 1977).
We are further guided in our analysis by several well-established principles. In considering whether the facts and inferences support a reasonable suspicion, we must view Agent Iglesias’s observations as a whole, not as single, disconnected occurrences. In sum, we view the whole mosaic rather than each tile. United States v. Vasquez, supra, 612 F.2d at 1343. Thus, the agent’s suspicion will be reasonable if the conduct as a whole would appear suspect to one familiar with the practices of narcotics couriers, albeit the pattern of behavior is innocuous to the untrained observer. United States v. Oates, supra, 560 F.2d at 61. Furthermore, although the conduct may be as consistent with guilt as with innocence, it may still indicate possible illicit activity and form the foundation for a valid stop. United States v. Vasquez, supra, at 612 F.2d at 1343.
Viewing the facts as a whole, as well as the rational inferences to be drawn from them, we agree with Judge Platt that Agent Iglesias’s suspicion was reasonable and that the initial investigatory stop was justified.5 Ms. Ramirez-Cifuentes arrived from Miami, a known “source city” for narcotics. See United States v. Forero-Rincon, supra, 626 F.2d at 222. As she disembarked from the aircraft, the agents’ attention was attracted by her nervous demeanor and her constant glancing about. See United States v. Vasquez-Santiago, supra, 602 F.2d at 1072. As she walked rapidly through the limited access area where it would be unusual to search for someone meeting her, she peered back repeatedly toward the gate, as if she were in fear of being followed. See United States v. Vasquez, supra, 612 F.2d at 1342. The agents then noticed that appellant was carrying, in addition to a small purse, an untagged black shoulder bag which appeared to be new and filled to capacity. Granted, the lack of an identification tag on a shoulder bag may not appear to be worthy of note to the untrained eye because such bags are frequently carried onto the airplane and are often untagged. It is a common factor in our prior airport cases, however, that drug couriers do not place their names upon the bags in which they carry contraband. See United States v. Forero-Rincon, supra, 626 F.2d at 222; United States v. Vasquez, supra, 612 F.2d at 1343; United States v. Price, supra, 599 F.2d at 496; United States v. Rico, supra, 594 F.2d at 322.
The agent’s curiosity aroused because Ms. Ramirez-Cifuentes’s apprehension and pattern of behavior resembled the conduct of narcotics traffickers he had observed during his years of experience, Iglesias began to follow her on her vigorously-paced journey toward the terminal exit. As she kept up her hurried gait, she brushed by an elderly woman who inquired in Spanish whether she had been on the Miami flight as if a delay, the agent could infer, might increase her chance of being intercepted. His suspicions could have been increased as appellant, when passing the security area on the left side of the corridor, carefully stayed far to the right. When Agent Iglesias noted that she, after claiming no baggage and leaving the terminal, stared directly back into the building and continued intently watching the area and people about her as she stood in the taxi line, he could deduce that she felt uneasy about being seen and could be hiding something. These actions and inferences, taken as a whole, and given Agent Iglesias’s expertise in monitoring airports for drug couriers, clearly justified the agent’s reasonable suspicion that Ms. Ra*343mirez-Cifuentes was engaged in transporting contraband. Accordingly, the initiation of the stop was not unreasonable.
Nor was the scope of the intrusion excessive. In reaching our determination, we are mindful that the fundamental purpose of the Fourth Amendment is to protect, through the imposition of a standard of reasonableness on law enforcement agents, the privacy and security of all citizens against arbitrary invasion. Justice White, writing for the Court, explained that
the permissibility of a particular law enforcement practice is judged by balancing its intrusion on the individual’s Fourth Amendment interests against its promotion of legitimate governmental interests. Implemented in this manner, the reasonableness standard usually requires, at a minimum, that the facts upon which an intrusion is based be capable of measurement against “an objective standard,” whether this is probable cause or a less stringent test.
Delaware v. Prouse, supra, 440 U.S. at 654, 99 S.Ct. at 1396 (footnotes omitted). Indeed, in the multitude of airport cases which have come before us, we have been cognizant of this delicate balance and have carefully measured the need for the stop against the nature of the intrusion suffered. See, e.g., United States v. Vasquez, supra, 612 F.2d at 1343-44; United States v. Price, supra, 599 F.2d at 499.
Here, the serious nature of cocaine trafficking and imminent departure of the suspected courier are factors augmenting the need for a stop. See United States v. Vasquez, supra, 612 F.2d at 1342; United States v. Vasquez-Santiago, supra, 602 F.2d at 1073; United States v. Oates, supra, 560 F.2d at 59. Furthermore, we are presented with no evidence of physical restraint, harassment, or intimidation. See United States v. Vasquez, supra, 612 F.2d 1343; United States v. Price, supra, 599 F.2d at 502; United States v. Magda, 547 F.2d 756, 759 (2d Cir. 1976), cert. denied, 434 U.S. 878, 98 S.Ct. 230, 54 L.Ed.2d 157 (1977). After Agent Iglesias identified himself and determined Spanish was Ms. Ramirez-Cifuentes’s native tongue, he politely repeated his statements in that language and stated he would like to ask her several questions. As he walked with her while the taxi queue moved forward, he asked to see her plane ticket, and after examining it and discovering it had been purchased for cash in the name of Rosa Gomez, requested identification. We have countenanced requests such as these with frequency. See, e.g., United States v. Forero-Rincon, supra; United States v. Vasquez, supra. When appellant could produce no identification and appeared increasingly apprehensive, Agent Iglesias asked if she would mind stepping out of line so that they could continue the conversation with greater ease. Only a few steps away from the queue and still on the sidewalk, he then inquired about drugs and requested permission to open the shoulder bag. The stop lasted but a brief time and was conducted in a public place. Clearly, this encounter cannot be termed anything other than minimally intrusive.
The Government, however, while agreeing that the stop was grounded in specific articulable facts, and was a most minor disturbance, would have us depart from the clear well-established standard by which this Court judges these so-called airport stops. Rather than proceeding by analyzing what we have deemed “seizures” in accord with the principles of reasonable suspicion and minimal intrusion, the Government invites us to rule that the conduct of Agent Iglesias in approaching Ms. Ramirez-Cifuentes was not a seizure at all.6 We *344decline the invitation. Since the stop was completely justified by an application of the principles of our traditional standard, we see no need to reach beyond them in the circumstances here. Such an extension, we believe, would only create unwarranted confusion.
B.
Ms. Ramirez-Cifuentes challenges the district court’s denial of her suppression motion on an additional ground: she contends that she did not consent to Agent Iglesias’s search of her shoulder bag. Whether appellant’s consent was voluntary, or was the product of coercion, is a question of fact to be determined by the district court after carefully considering the totality of the circumstances. Schneckloth v. Bustamonte, 412 U.S. 218, 227, 93 S.Ct. 2041, 2047, 36 L.Ed.2d 854 (1973). Judge Platt found no threatening conduct on the part of Agent Iglesias and gave credit to the agent’s testimony that appellant had twice given her consent to the search of her bag. In addition, when the search revealed a tightly-wrapped parcel which was too heavy to contain items of clothing as appellant had claimed, the agent asked to open the package, and Ms. Ramirez-Cifuentes gave her permission. Moreover, the search was conducted in a public place, an airline terminal, only a short distance from the taxi line where appellant was initially stopped. Since the district court’s finding that consent was voluntary is not clearly erroneous, Judge Platt’s denial of the motion to suppress must stand. See United States v. Forero-Rincon, supra, 626 F.2d at 224; United States v. Vasquez, supra, 612 F.2d at 1347.
In sum, we conclude, by applying the standard established by our prior decisions, that the stop at LaGuardia Airport was grounded on specific and articulable facts which justified a reasonable suspicion that appellant was engaging in illegal narcotics transportation. Furthermore, it was brief and minimally intrusive. Given the compelling interest in deterring the flow of controlled substances which affect the health and well-being of the citizens of our Nation, and the elusive nature of trafficking in narcotics, the stop was necessary. Because neither the stop nor the search violated Ms. Ramirez-Cifuentes’s Fourth Amendment right against unreasonable searches and seizures, Judge Platt properly denied the motion to suppress. Accordingly, we affirm the judgment of conviction.
. Union Pacific Ry. Co. v. Botsford, 141 U.S. 250, 251, 11 S.Ct. 1000, 1001, 35 L.Ed. 734, 737 (1891).
. Ms. Ramirez-Cifuentes’s guilty plea was entered pursuant to an agreement between appellant and the Government preserving her right to appeal the district court’s denial of her motion to suppress.
. 21 U.S.C. § 841 provides in pertinent part:
(a) Except as authorized by this subchap-ter, it shall be unlawful for any person knowingly or intentionally—
(1) to manufacture, distribute, or dispense, or possess with intent to manufacture, distribute, or dispense, a controlled substance;
. According to Agent Iglesias, the reference to a social security card is a common reply given by illegal aliens. His suspicions were proven correct because appellant is indeed an illegal alien.
. Judge Platt noted in his opinion of November 20, 1981 that “a law enforcement officer may speak with anyone he wishes and, as long as that person’s freedom of movement is not restrained in any way whatsoever, the Fourth Amendment is not implicated at all.” Recognizing that we have not adopted this approach to determining the constitutionality of an investigatory stop, he proceeded to evaluate the permissibility of the stop in terms of the standard we have repeatedly employed — whether the initial encounter was based on reasonable suspicion.
. We are not unaware of possible authority for this position. In United States v. Mendenhall, 446 U.S. 544, 100 S.Ct. 1870, 64 L.Ed.2d 497 (1980), a case involving an investigatory stop at an airport, Justices Stewart and Rehnquist concluded that the initial encounter of the Drug Enforcement Administration agents with Ms. Mendenhall did not constitute a “seizure” within the meaning of the Fourth Amendment. Chief Justice Burger and Justices Blackmun and Powell, however, determined that the agents had acted properly because, assuming they had seized Ms. Mendenhall, they had reasonable suspicion that she was engaged in illegal activity. Justices Brennan, White, Marshall, and Stevens dissented stating that she *344had been unlawfully seized. Since there is no majority opinion, Mendenhall provides us with little guidance. Nor do we find that Reid v. Georgia, 448 U.S. 438, 100 S.Ct. 2752, 65 L.Ed.2d 890 (1980), another airport stop case, in which the Court ruled that a seizure was unsupported by reasonable suspicion when grounded primarily on a drug courier profile, clarifies the situation. Indeed, the Court does not appear to have considered explicitly whether a seizure occurred at the initial encounter. Moreover, the concurring opinion by Justice Powell, joined by the Chief Justice and Justice Blackmun, pointed out that the Court had not addressed this issue. See id. at 442-43, 100 S.Ct. at 2754.
We recognize that several other Circuits have attempted to draw the line between encounters which do not implicate Fourth Amendment concerns and those which do. See, e.g., United States v. Berry, 670 F.2d 583 (5th Cir. 1982) (en banc); United States v. Wylie, 569 F.2d 62 (D.C.Cir.1977), cert. denied, 435 U.S. 944, 98 S.Ct. 1527, 55 L.Ed.2d 542 (1978). We decline to follow their example, however, because we believe the stop in the instant case was clearly justified by the standard this Court has consistently applied. Thus, no purpose would be served by marking boundaries where none need to be inscribed.