Federal marshals have secretly used powerful cellphone surveillance tools to hunt nearly 6,000 suspects throughout the United States, according to newly-disclosed records in which the agency inadvertently identified itself as the nation’s most prolific known user of phone-tracking devices.
The fact that the U.S. Marshals Service uses cellphone trackers, commonly known as stingrays, has long been among law enforcement’s worst-kept secrets, though the agency still refuses to acknowledge it. The Marshals Service confirmed its use of the devices to USA TODAY only in the process of trying to keep it secret, rejecting a Freedom of Information Act request for a copy of its log of cases in which agents had used stingrays.
The Marshals Service’s response to that request included an almost totally censored spreadsheet listing its stingray cases, with information about the cases stripped out line by line, which made it possible to count the number of entries the agency had made on its log of stingray uses. The agency described the log in a letter as “a listing of IMSI catcher use,” using another name for the technology that intercepts cellphone signals.
Stingrays are suitcase-sized devices that can pinpoint a cellphone’s location within a few yards by posing as a cell tower. In the process, they also intercept information about other cellphones that happen to be nearby, a fact that has raised concerns among privacy advocates and some lawmakers. Dozens of police departments use the devices, often concealing that fact from suspects and their lawyers.