Department of Justice documents obtained by the ACLU reveal that the department has not been “forthright” with California judges about its use of a controversial and sophisticated cellphone tracking device, according to the ACLU.
Federal investigators, according to the ACLU’s analysis of Justice Department emails, have “routinely” used a portable technology called a “stingray,” which masquerades as a cellphone tower by emitting a powerful signal. The goal is to trick nearby cellphones into connecting to the stingray, which can then gather data transmitted by the phones.
The emails —obtained through a Freedom of Information Act request filed by the ACLU of Northern California and the San Francisco Bay Guardian — came to light as part of a larger investigation into the methods used by the Justice Department to track down a suspect in an electronic tax fraud scheme.
The Justice Department sought a court order mandating that Verizon hand over location data for the phone of the suspect, Daniel Rigmaiden. While the Justice Department’s request mentioned that it would use a mobile location tracking device, it did not specify that a stingray would be used.
Rigmaiden, who was indicted in 2008, has since argued that he should have access to details about the investigative methods used to track him down. A federal magistrate judge has been sympathetic to that position.
The Justice Department has also argued that in-field use of the device was an innocent mistake by agents “using a relatively new technology,” but the emails obtained by the ACLU demonstrate that the government’s undeclared in-field use of the stingray was not isolated to the Rigmaiden case.
For example, an email chain dated May 2011 showed that federal investigators were still using the technology in the field, although their court applications for surveillance failed to “make that explicit.”
The federal government has argued, however, that tools like the stingray can be used without a search warrant because they do not capture the content of communications made with cellphones. Instead, they capture only limited data, such as the phone numbers dialed.
Federal officials also contend that they delete the tracking data collected during stingray surveillance operations.
The Electronic Privacy Information Center (EPIC) also obtained documents from the FBI in February 2013 that revealed the technology not only targeted Rigmaiden, but also innocent cellphones within the vicinity of the signal.