The House Subcommittee on Information Technology will examine law enforcement use of "Stingrays," a technique for tracking cell phones users. The Department of Justice adopted guidelines that require a warrant before using Stingray devices to track the location of mobile devices. Senators Grassley and Leahy recently asked DHS Secretary Jeh Johnson to adopt a similar policy for DHS. California passed a law requiring a warrant for a Stingray. 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.