US SUPREME COURT DECISIONS

Based on their discovery of sets of distinctive human footprints in the desert, Border Patrol officers deduced that on a number of occasions groups of from 8 to 20 persons had been guided by a person, whom they designated "Chevron," from Mexico across an area of desert in Arizona, known to be heavily trafficked by aliens illegally entering the country. These groups of aliens proceeded to an isolated point on a road to be picked up by a vehicle; the officers deduced the vehicle probably approached from the east and returned to the east after the pickup. They also surmised, based on the times when the distinctive tracks were discovered, that "Chevron" generally traveled on clear nights during or near weekends, and arrived at the pickup point between 2 a.m. and 6 a.m. On the basis of this information, the officers stationed themselves at a point east of the probable pickup point on a night when they believed there was a strong possibility that "Chevron" would be smuggling aliens. The officers observed a pickup truck with a camper shell suitable for carrying sizable groups pass them heading west, and then observed the same vehicle return within the estimated time for making a round trip to the pickup point. The officers stopped the vehicle, which was being driven by respondent Cortez and in which respondent Hernandez-Loera, who was wearing shoes with soles matching the distinctive "chevron" shoeprint, was a passenger. Cortez voluntarily opened the door of the camper, and the officers then discovered illegal aliens. Prior to trial on charges of transporting illegal aliens, respondents sought to suppress the evidence of the presence of the aliens discovered as a result of the stopping of their vehicle, contending that the officers did not have adequate cause to make the investigative stop. The District Court denied the motion, and respondents were convicted. The Court of Appeals reversed, holding that the officers lacked a sufficient basis to justify stopping the vehicle, and thus respondents' Fourth Amendment rights were violated.

Held: The objective facts and circumstantial evidence justified the investigative stop of respondents' vehicle. Pp. 449 U. S. 417-422.

(a) In determining what cause is sufficient to authorize police to stop a person, the totality of the circumstances -- the whole picture -- must be taken into account. Based upon that whole picture, the detaining chanrobles.com-red

Page 449 U. S. 412

officers must have a particularized and objective basis for suspecting the particular person stopped of criminal activity. The process of assessing all of the circumstances does not deal with hard certainties, but with probabilities, and the evidence collected must be weighed as understood by those versed in the field of law enforcement. Also, the process must raise suspicion that the particular individual being stopped is engaged in wrongdoing. Pp. 449 U. S. 417-418.

(b) This case implicates all of these principles -- especially the imperative of recognizing that, when used by trained law enforcement officers, objective facts, meaningless to the untrained, allow for permissible deductions from such facts to afford a legitimate basis for suspicion of a particular person and action on that suspicion. Pp. 449 U. S. 418-421.

(c) The intrusion upon privacy associated with this stop was limited, and "reasonably related in scope to the justification for [its] initiation." Terry v. Ohio, 392 U. S. 1, 392 U. S. 29. Based upon the whole picture, the officers, as experienced Border Patrol agents, could reasonably surmise that the particular vehicle they stopped was engaged in criminal activity. Pp. 449 U. S. 421-422.

595 F.2d 505, reversed.

BURGER, C.J.,delivered the opinion of the Court, in which BRENNAN, WHITE, BLACKMUN, POWELL, REHNQUIST, and STEVENS, JJ., joined. STEWART, J., filed an opinion concurring in the result, post, p. 449 U. S. 422. MARSHALL, J., concurred in the judgment.