Police in Florida have offered a startling excuse for having used a controversial "stingray" cellphone tracking gadget 200 times without ever telling a judge: the device’s manufacturer made them sign a non-disclosure agreement that they say prevented them from telling the courts.

Local police are increasingly able to scoop up large amounts of cellphone data using new technologies, including cell tower dumps and secret mobile devices known as Stingrays.

For more than a year, federal authorities pursued a man they called simply "the Hacker." Only after using a little known cellphone-tracking device—a stingray—were they able to zero in on a California home and make the arrest.

StingRay is a multichannel software defined radio that performs network base station surveys, Dialed Number and registration collection, mobile interrogation, and target tracking.