The Department of Justice (DOJ) has announced a policy for the use of cell-site simulators (commonly called “stingrays”). The policy, which covers federal agencies like the FBI, generally requires that officers get warrants before using the contraptions, and that they let judges know when they intend to use the equipment. (The Department of Homeland Security announced a similar stingray policy in October 2015.)
Stingrays act like cellphone towers; they communicate with nearby phones. In that way, they learn the devices’ location. They’re also capable of grabbing personal data like emails and texts from the phones, and they connect with many phones—including those of innocent bystanders—at once.
The DOJ policy doesn’t apply to state and local law enforcement agencies, and it has potentially broad exceptions. For more on it, see DOJ’s New “Stingray” Policy Offers Protections, Limitations.