The Internal Revenue Service (IRS) used its stingray to track 44 cellular devices, IRS Commissioner John Koskinen told Senator Ron Wyden (D-Ore.) in a letter dated Nov. 25. 

The letter was sent in response to a question asked during an Oct. 27 Senate Finance Committee hearing concerning the IRS's use of the surveillance technology.

He said the agency's Criminal Investigation (IRS-CI) has used the stingray to assist in 11 federal grand jury investigations, led by the U.S. Attorney's Office (USAO), to tracked 37 devices. The IRS also used the device in four non-IRS-CI cases, including a Drug Enforcement Administration (DEA) federal grand jury narcotics investigation that tracked one device and three state level investigations that tracked six devices. 

Koskinen wrote the IRS-CI division procured the device in October 2011 and that the IRS began the process of obtaining a new “cell-site simulator” in July 2015, though it has yet to receive it.