For years, the phone-tracking devices known as Stingrays have been one of law enforcement's most closely guarded secrets — but a new report from The Wall Street Journal suggests that may be about to change. According to the report, the Justice Department is in the midst of a full review of how law enforcement agencies use the devices, and may be about to reveal significant details about how and where the devices are typically deployed. For more than a decade, Stingrays have been shrouded in intense secrecy, and criminal prosecutions are often abandoned rather risking having to admit in court that the devices were used.

Stingrays are typically used to locate a specific phone in a crowd, sometimes even from a plane flying overhead, although they can also be configured to pull more comprehensive data from the phone. The system works by impersonating a 2G cell tower, which doesn't require any authentication to connect to a phone. As long as the Stingray is the strongest signal in the area, phones will automatically connect to the device, giving away their location and basic identification data. Since no larger network data can be received through that connection, the devices often result in significant service disruptions in the areas where they are used.

Stingrays are also notable for how far they've reached into the law enforcement world. A number of Justice Department agencies are known to have access to the devices, including the US Marshals, but the signal interceptors are also increasingly common in local law enforcement. The EFF has compiled legal evidence of Stingray use by local departments in Baltimore, Sarasota, and Tacoma, and it's likely there are many more departments that simply haven't referred to their devices in court. A recent test run in Washington, DC found as many as 18 different Stingray-like service disruptions in just two days of driving.