The FBI may not track the locations of cell phone users without showing evidence that a crime occurred or is in progress, two federal judges ruled, saying that to do so would violate long-established privacy protections.
In separate rulings over the past two weeks, judges in Texas and New York denied FBI requests for court orders that would have forced wireless carriers to continuously reveal the location of a suspect's cell phone as part of an ongoing investigation. Other judges have allowed the practice in other jurisdictions, but the recent rulings could change that.
Depending on a wireless phone's capabilities, carriers can determine either precise or rough locations of users when they make or receive calls, a feature primarily used for emergencies.
The rulings come as controversy mounts over the federal government's ability to conduct domestic surveillance. Privacy advocates continue to criticize the Patriot Act, enacted after the Sept. 11, 2001, terrorist attacks. That law broadened the powers of law enforcement to monitor citizens under suspicion of terrorist activity.
On Tuesday, a coalition of technology and privacy groups filed suit challenging a Federal Communications Commission order that would make it easier for law enforcement to monitor e-mail and other Internet-based communication.
In the New York and Texas cases, the courts approved FBI requests for other information from the wireless carriers, including logs of numbers a cell phone user called and received calls from.
Court orders for that information require law enforcement agencies to show only that the information is relevant to an ongoing investigation.
But the FBI also sought cell-site locations, which the courts said amounted to the ability to monitor someone's movements. The judges ruled that such information requires law enforcement to show "probable cause" that a crime has been or is being committed.
That requirement, which also is required for a search warrant, is a long-standing legal mandate designed to protect against overzealous or improper investigations, both judges said.
"When the government seeks to turn a mobile telephone into a means for contemporaneously tracking the movements of its user, the delicately balanced compromise that Congress has forged between effective law enforcement and individual privacy requires a showing of probable cause," wrote federal Magistrate Judge James Orenstein of the U.S. District Court for the Eastern District of New York.
Justice Department officials countered that courts around the country have granted many such orders in the past without requiring probable cause. Such orders granted quickly, they said, are critical in tracking fugitives and kidnappers, for example.
The officials said that in their interpretation, cell phones are not tracking devices. And even if they are, they said, not all tracking devices require a showing of probable cause.
The officials, who requested anonymity because there may be further litigation on this issue, said that only when someone has an expectation of privacy does the higher threshold need to be met and that cell phone use does not qualify.
Both Orenstein and federal Magistrate Judge Stephen Wm. Smith of the U.S. District Court for the Southern District of Texas, rejected that argument, and said the government was relying on creative and contrived legal theories.
Kevin Bankston, staff counsel of the Electronic Frontier Foundation, a privacy advocacy group that filed court briefs opposing the government's position, said the framers of the Constitution recognized that sometimes, investigations might be slowed to preserve broader privacy rights.
He also said that the government's arguments make him wonder what other tactics the FBI is employing that might exceed legal authority.