The ruling rejected the government's argument that people give up privacy rights in information, voluntarily handed over to a third party. Reuters

An appeals court in Richmond, Virginia, ruled Wednesday that police are not authorized to track cellphone records in criminal investigations without obtaining a search warrant. The ruling conflicts with two other federal appeals court verdicts, increasing the possibility that the U.S. Supreme Court will now have to take up the issue.

Wednesday’s ruling by a three-judge panel of the 4th U.S. Circuit Court of Appeals said that the Fourth Amendment requires law enforcement officials to obtain a warrant before seeking information about a person’s historical mobile phone location from the cellphone company. The ruling suggests that citizens do not have to give up their privacy rights just because their cellphone providers know their whereabouts.

“Today’s opinion is a full-throated defense of Fourth Amendment privacy rights in the digital age,” Nathan Freed Wessler, an attorney with the American Civil Liberties Union (ACLU) Speech, Privacy, and Technology Project, said in a statement.

Last week, attorneys asked the U.S. Supreme Court to evaluate an appeals court ruling in a Florida case, which stated that search warrants are not required to track cellphone locations in criminal investigations. In the case, the government obtained seven months of historical cellphone location data of two suspects using a court order instead of a warrant.

“Cellphone location records can reveal some of the most private details about our lives by showing where we go and who we spend time with,” Wessler said. “Requiring a warrant for access to this information is an important protection against unjustified government intrusions.”

According to the government, people surrender their privacy rights when they voluntarily hand over information to cellphone companies. But the latest ruling rejected the argument, saying that this information is protected by the Fourth Amendment because it can reveal a person’s private details of movements over time.

“People cannot be deemed to have volunteered to forfeit expectations of privacy by simply seeking active participation in society through use of their cellphones,” the court said in the ruling.