Following revised policies from other federal law enforcement agencies, the Internal Revenue Service now says it will require the use of a warrant when deploying a stingray, also known as a cell-site simulator.
In a new letter to an Oregon senator, IRS Director John Koskinen wrote that the stingray has only been used as part of 11 grand jury investigations to track 37 phones. The IRS stingray has also been used to assist with four other non-IRS investigations both at the federal and the state level. According to the document, the IRS first obtained its stingray in October 2011, and it's attempting to procure a second.
Stingrays, also known as cell-site simulators, can be used to determine a phone’s location by spoofing a cell tower, and in some cases they can intercept calls and text messages. Once deployed, the devices intercept data from a target phone as well as information from other phones within the vicinity. In late October, Koskinen told a Senate committee that the IRS stingrays are "only used in criminal investigations."