The U.S. Supreme Court case Terry v. Ohio ruled that the Fourth Amendment to the U.S. Constitution allows police officers to stop, detain and frisk individuals without probable cause or a warrant if the officer can prove a reasonable suspicion of criminal activity. The Supreme Court ruled that the Fourth Amendment only protects against unreasonable searches and that the police have the flexibility to investigate and prevent crime.
In 1963 in Cleveland, Ohio, police officer Martin McFadden saw three men acting suspiciously. McFadden observed John Terry, Richard Chilton and a third man, known only as Katz, pacing back and forth in front of a jewelry store and repeatedly peering into the store's window. McFadden believed that the men were planning to rob the store. The officer approached the men and asked their names. When the men muttered unintelligible responses, McFadden patted down Terry's overcoat and discovered a gun. McFadden also found a gun in Chilton's overcoat. Katz was unarmed.
Terry and Chilton were charged with carrying concealed weapons. After being found guilty, Terry took his case to the Supreme Court, claiming that Officer McFadden violated his Fourth Amendment rights protecting him from unlawful searches and seizures. The Supreme Court handed down its decision in favor of the state on June 10, 1968.