In 1968 the Supreme Court addressed the issue in terry v. ohio, 392 U.S. 1, 88 S. Ct. 1868, 20 L. Ed. 2d 889. In Terry an experienced plainclothes officer observed three men acting suspiciously; they were walking back and forth on a street and peering into a particular store window. The officer concluded that the men were preparing to rob a nearby store and approached them. He identified himself as a police officer and asked for their names. Unsatisfied with their responses, he then subjected one of the men to a frisk, which produced a gun for which the suspect had no permit. In this case the officer did not have a warrant nor did he have probable cause. He did suspect that the men were "casing" the store and planning a Robbery. The defendants argued the search was unreasonable under the Fourth Amendment because it was not supported by probable cause.