WASHINGTON (AP) - The Supreme Court says police generally need a search warrant if they want to track criminal suspects' movements by collecting information about where they've used their cellphones.

The justices' 5-4 decision Friday is a victory for privacy in the digital age.

That's a big change from the old days when authorities could go to the phone company and obtain information about the numbers dialed from a home telephone without presenting a warrant.

Chief Justice John Roberts wrote the majority opinion, joined by the court's four liberals.