Page "Fourth Amendment to the United States Constitution" Paragraph 21

Under Terry v. Ohio, law enforcement officers are permitted to conduct a limited warrantless search on a level of suspicion less than probable cause under certain circumstances.

In Terry, the Supreme Court ruled that when a police officer witnesses " unusual conduct " that leads that officer to reasonably believe " that criminal activity may be afoot ", that the suspicious person has a weapon and that the person is presently dangerous to the officer or others, the officer may conduct a " pat-down search " ( or " frisk ") to determine whether the person is carrying a weapon.

To conduct a frisk, officers must be able to point to specific and articulatory facts which, taken together with rational inferences from those facts, reasonably warrant their actions.

A vague hunch will not do.

Such a search must be temporary and questioning must be limited to the purpose of the stop ( e. g., officers who stop a person because they have reasonable suspicion to believe that the person was driving a stolen car, cannot, after confirming that it is not stolen, compel the person to answer questions about anything else, such as the possession of contraband ).