Mobile-Phone Privacy Case Draws U.S. Supreme Court Scrutiny

(Bloomberg) -- The U.S. Supreme Court agreed to take up a major constitutional test of digital privacy, agreeing to consider whether prosecutors need a warrant to obtain mobile-phone tower records that show someone's location over days or even months.

Critics say prosecutors obtain massive amounts of data without ever having to meet the “probable cause” standards for a search warrant. The largest telecommunications providers receive tens of thousands of requests for location information a year under the 1986 Stored Communications Act, which doesn't require a warrant.

The court will hear an appeal from Timothy Ivory Carpenter, who is seeking to overturn his conviction for taking part in nine armed robberies of Radio Shacks and T-Mobile stores in the Detroit area. At trial, prosecutors used data obtained from mobile-phone carriers to show that Carpenter was within a half-mile to two miles of the location of each of the robberies when they occurred.

Wireless carriers typically log and keep records that show the cell sites where their customers' calls begin and end, along with other information about the calls.

The Supreme Court under Chief Justice John Roberts has been protective of digital privacy rights. The court said in 2014 that the Constitution's Fourth Amendment generally requires police to get a warrant before searching the phone of a person being arrested.

Two years earlier, the high court put limits on the power of police to attach tracking devices to cars.

The case is Carpenter v. United States, 16-402.

To contact the reporter on this story: Greg Stohr in Washington at gstohr@bloomberg.net.

To contact the editors responsible for this story: Kevin Whitelaw at kwhitelaw@bloomberg.net, Laurie Asseo, Ros Krasny