By Cory Bennett - 11/21/14 05:29 PM EST
A judge Friday unsealed a trove of court documents that could shed light on a secret cellphone tracking program used by police nationwide.
The judge in Charlotte, N.C., acted after a petition from the Charlotte Observer to make the documents public.
Together, the requests give the most complete account yet of the U.S. law enforcement tactic, about which little is known.
The records date back to 2010, meaning police made requests roughly twice a week. There were no records before 2010. The police requests are “rarely, if ever” denied, the Observer reported, and judges at times appeared to not know exactly what they were authorizing.
As a result, the Mecklenburg County District Attorney’s Office, which had not previously seen the documents, will review each case in which the technology was used.
Such police requests are rarely made public for fear of disclosing confidential investigative techniques. Privacy advocates argue transparency is needed to ensure police are following the law.
According to the Observer, StingRay works by imitating a cell tower. From there, the police can collect the serial number, geolocation and other data from any phone, laptop or device that connects to the tower.
Records revealed police had used StingRay to track criminals suspected of crimes ranging from murder to rape to felony possession of stolen goods.
The police department has defended the technique, arguing it is used judiciously for serious crimes and with a respect for constitutional rights.
The release could have national implications.
Civil liberties groups, lawmakers and law enforcement officials are locked in a battle over how — and where — government investigators should file warrants for digital surveillance.
The FBI has been seeking the authority to remotely search or track electronic devices even if they don't know the location of the device. Privacy advocates have vocally resisted the attempt.
Privacy groups are also pressuring Congress to bring transparency to the court that approves the National Security Agency’s digital surveillance requests.
An effort that would have reformed the court overseeing the agency failed to move forward this week in the Senate.