In Terry v. Ohio, 392 U.S. 1, 88 S. Ct. 1868, 20 L. Ed. 2d 889 (1968), the United States Supreme Court ruled that the Fourth Amendment to the United States Constitution permits a law enforcement officer to stop, detain and frisk persons who are suspected of criminal activity without first obtaining their consent even though the officer may lack a warrant to conduct a search or probable cause to make an arrest. Now known as a Terry Stop, this type of police encounter is constitutionally permissible only when an officer can articulate a particularized, objective and reasonable basis for believing that criminal activity may be afoot or that a given suspect may be armed and dangerous.
The Court said that no police officer may lawfully stop and detain a person for questioning unless the officer first observes unusual conduct that arouses a reasonable suspicion of criminal activity. A stop may be no longer than necessary to confirm or dispel an officer’s suspicion and must not be unnecessarily restrictive or intrusive. During the period of detention, no searches may be performed unless the officer has an objective and particularized basis for believing the suspect is armed and dangerous. Any search must be limited to the suspect’s outer clothing and may be performed only for the purpose of discovering concealed weapons. Evidence obtained during searches that comport with these restrictions is admissible under the Fourth Amendment. Evidence obtained in violation of the limitations set forth in Terry may be suppressed under the exclusionary rule.