Illinois v. Wardlow

Officers patrolling a high-drug-crime area saw Wardlow (defendant) standing beside a building holding an opaque bag, and when he noticed their car he immediately fled; officers chased and caught him, and an immediate pat-down for weapons revealed a handgun, leading to his arrest for unlawful weapon possession by a felon. The trial court upheld the stop and frisk, the court of appeals reversed for lack of reasonable suspicion, and the state supreme court affirmed, reasoning flight alone, even in a high-crime area, could reflect a lawful refusal to engage with police; the U.S. Supreme Court granted certiorari.