Senator Chuck Grassley and Senator Patrick Leahy have asked DHS Jeh Johnson to enact a policy on cell phone surveillance devices, known as "Stingrays." The Department of Justice recently adopted new guidelines on Stingray use that requires agents to obtain a search warrant before employing Stingrays. The DOJ policy also prohibits officers from using Stingrays to intercept communications, and requires that all non-target data be deleted after use. Documents obtained by EPIC in a FOIA lawsuit revealed the FBI was using the cell-site simulators without a warrant. EPIC also filed amicus briefs in U.S. v. Jones and State v. Earls, arguing that a warrant is required to obtain location information from cell phone subscribers.