Police get restrictions on tracking cellphone users

WASHINGTON » Police generally need a warrant to look at records that reveal where cellphone users have been, the Supreme Court ruled Friday in a big victory for privacy interests in the digital age.

The justices’ 5-4 decision marks a big change in how police may obtain information that phone companies collect from the ubiquitous cellphone towers that allow people to make and receive calls and transmit data.

Chief Justice John Roberts, joined by the court’s four liberals, said cellphone location information “is detailed, encyclopedic and effortlessly compiled.” Roberts wrote that “an individual maintains a legitimate expectation of privacy.”

Roberts said the court’s decision is limited to cellphone tracking information and does not affect other business records, including those held by banks. He also wrote that police still can respond to an emergency and obtain records without a warrant.