US Marshals accidentally confirm they secretly used stingray to track thousands of cellphones

The federal agency had never confirmed the longstanding rumor, until Tuesday.

Federal marshals have used a cell phone tracking tool referred to as "stingray" to hunt roughly 6,000 fugitives.

Stingrays are said to be the worst kept secret in law enforcement, and their use is shrouded in secrecy. The suitcase-sized trackers can pinpoint the location of a cellphone within a few yards by imitating a legitimate cellphone tower.

It's long been believed the US Marshals Service has utilized the technology to track suspects, but it's never been confirmed -- until Tuesday, when it was accidentally disclosed as part of a Freedom of Information request made by USA Today.

The Marshals Service federal agency rejected the news outlet's request for a copy of its cases that federal agents had used the cell phone tracking technology. Portions of the requested document were blacked out, but not the number of suspects.

It's believed the stingrays also intercept information of other cell phones in the area when posing as a cell phone tower.

Several local police agencies use stingrays without suspects or their lawyers knowing, the news outlet said. According to the American Civil Liberties Union, 42 law enforcement agencies in 17 states own stingray technology.

We've reached out to the US Marshals Service for more information.