## Facts

- Chicago police were patrolling an area known for heavy narcotics trafficking.
- Officers observed William Wardlow holding an opaque bag.
- Upon seeing a caravan of police vehicles converge, Wardlow fled.
- Officers chased and stopped Wardlow and conducted a protective pat-down.
- During the encounter, an officer squeezed the bag, felt a heavy hard object similar to a gun, opened it, and found a loaded .38-caliber handgun.
- Wardlow was charged and convicted of unlawful use of a weapon by a felon after the trial court denied his motion to suppress the gun.

## Issues

1. Whether sudden, unprovoked flight upon noticing police officers, in a high-crime area, provides reasonable suspicion to justify an investigatory stop under *Terry v. Ohio*.
2. Whether the Fourth Amendment permits a stop based on commonsense inferences from evasive conduct and contextual factors rather than empirical proof.

## Decision

- The Supreme Court reversed the Illinois Supreme Court and held the stop was consistent with the Fourth Amendment.
- The Court held that officers may consider the high-crime character of an area as part of the circumstances, though it is not sufficient by itself.
- The Court held that unprovoked “headlong flight” is strongly indicative of evasion and is a relevant factor supporting reasonable suspicion.
- Considering the totality of the circumstances—high-crime location and Wardlow’s immediate flight—the officers had reasonable suspicion that criminal activity might be afoot and could briefly detain him to investigate.
- The Court rejected a requirement of scientific or statistical certainty, permitting reliance on commonsense judgments and inferences about human behavior.
- Justice Stevens, joined by Justices Souter, Ginsburg, and Breyer, agreed no per se rule should govern but dissented from the majority’s application, stressing that flight may have innocent explanations and that the record did not justify reasonable suspicion in this case.

## Legal Principles

- Under *Terry*, police may conduct a brief investigatory stop when they have a reasonable, articulable suspicion that criminal activity is afoot.
- “Reasonable suspicion” requires a minimal level of objective justification and is assessed under the totality of the circumstances.
- Presence in a high-crime area is relevant context but does not, standing alone, establish reasonable suspicion.
- Nervous, evasive behavior—especially unprovoked headlong flight upon noticing police—may be treated as suggestive of wrongdoing and may contribute materially to reasonable suspicion.
- An individual may ignore police and go about their business; however, refusal to cooperate differs from headlong flight, which may justify further investigation.
- Courts may evaluate reasonable suspicion using commonsense inferences about behavior without demanding empirical validation.

## Conclusion

The Court held that unprovoked headlong flight in a high-crime area can provide reasonable suspicion for a *Terry* stop, treating the location as contextual and the flight as probative evasive conduct under the totality-of-the-circumstances analysis.


Illinois v. Wardlow, 528 U.S. 119 (2000)