Law enforcement officials violated the Constitutional rights of a defendant by installing a GPS tracking device on his vehicle without a search warrant, the U.S. Supreme Court said in a unanimous decision on Monday.

Information from the device was used to indict Antoine Jones on drug trafficking charges. But since the evidence was obtained in violation of his Fourth Amendment right against unreasonable searches, it can't be used in court, the justices ruled.

"It is important to be clear about what occurred in this case: The Government physically occupied private property for the purpose of obtaining information," Justice Antonin Scalia wrote for the court. "We have no doubt that such a physical intrusion would have been considered a 'search' within the meaning of the Fourth Amendment when it was adopted."

Law enforcement authorities in fact had obtained a search warrant to place the device on Jones' vehicle while he was within the boundaries of the District of Columbia and within a 10-day period. But the device was attached on the 11th day and in Maryland, the court noted.

Get the Story:
Supreme Court: Warrants needed in GPS tracking (The Washington Post 1/24)
Justices Say GPS Tracker Violated Privacy Rights (The New York Times 1/24)

Supreme Court Decision:
US v. Jones (January 23, 2012)