Argued October 17, 1967.Decided December 18, 1967.

Mr. Justice CAPERS delivered the opinion of the Court.1

We are not precisely told how Charles Katz, the petitioner, came to the FBI’s attention as someone involved in illegal gambling. But clearly by early 1965, the FBI considered the petitioner a person worth keeping an eye on. What we are told is that starting around February 4, 1965, FBI agents began tailing the petitioner, and continued tailing him for about two weeks. Their surveillance of the petitioner, presumably without his knowledge, revealed that the petitioner had a daily habit of making telephone calls from a particular row of telephone booths on Sunset Boulevard in Los Angeles. Further investigation, presumably through the telephone company, revealed that the petitioner’s calls were placed to a number in Massachusetts, which number the FBI traced to a known gambler. Armed with this information, but lacking a warrant, the FBI secretly placed a recording device on top of the bank of phones the petitioner had been using.

Justice Marshall* delivered the opinion of the Court.

In this case, we decide whether it is consistent with the Fourth Amendment for a police officer who observed a traffic violation to use that violation as the justification to perform a racially-selective traffic stop, or as the pretext to investigate a crime for which the officer does not have probable cause. We answer that question in the negative.

Argued December 12, 1967.Decided June 10, 1968.

Mr. Chief Justice WARREN1 delivered the opinion of the Court.

Is the police practice known as “stop and frisk” constitutional? This case presents frisky questions about the power of police to cop a feel. Our decision is a minstrelsy in three acts, with elements of burlesque.

Argued November 2, 1999.Decided January 12, 2000.

Justice L. SONG RICHARDSON delivered the opinion of the Court*

The issue in this case is whether a person’s sudden and unprovoked flight from a clearly identifiable police officer, who is patrolling a high crime area, is sufficiently suspicious, without more, to justify a temporary investigatory stop pursuant to Terry v. Ohio. We hold that it is not.