A bipartisan House Oversight and Government Reform Committee report released today urges Congress to pass legislation to regulate cell-site simulation surveillance devices like the Stingray.

The devices, used by local and federal law enforcement agencies around the country, have been controversial, both for their power to track mobile devices and the secrecy often accompanying their use. As the report notes, the devices are still often used by local law enforcement agencies without warrants, instead relying on various lower standards of evidence.

The committee’s investigation, which last year prompted the Justice Department and Department of Homeland Security to change their policies on when to require a warrant before using the devices, found that the Justice Department uses 310 of the devices and spent $71 million on them between fiscal years 2010 and 2014. Homeland Security has 124 devices and spent $24 million in the same period.

The investigation also revealed that at least $1.8 million from DHS went to state and local law enforcement agencies to purchase the devices, although that number may be an undercount, as the agency does not keep records specific to the devices.

The committee recommends that agencies become more “candid” about the devices, and urges states to pass legislation that would “require, with limited exceptions, issuance of a probable cause based warrant prior to law enforcement’s use of these devices.”

But to ensure a cohesive set of laws, the report reads, “Congress should pass legislation to establish a clear, nationwide framework for when and how geolocation information can be accessed and used.”