Silent sting

To find criminal suspects, federal agents use a device that tracks everyone else too

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rebecca@sfbg.com

If the FBI is trying to track down a suspect in your neighborhood, investigators could sweep up information from your mobile device just because you happen to be nearby.

It's been going on for years with little public notice or attention.

Records obtained through the Freedom of Information Act request shed new light on a surveillance device known as a Stingray that allows law enforcement to automatically collect cell phone data from potentially hundreds of subscribers in a given area — even when the vast majority of those affected have nothing to do with the criminal investigation at hand.

The documents came in response to an FOIA request from the Bay Guardian and the Northern California Chapter of the American Civil Liberties Union.

Stingray is a brand name; the devices might also be known as a Triggerfish, a digital analyzer, a cell site emulator, or an IMSI catcher, the latter being a technical term describing the gadget's ability to detect International Mobile Subscriber Identities. It essentially behaves like cell phone tower, putting out a strong signal that tricks mobile devices into connecting automatically.

If there are 200 cell phone customers in an area where it's being deployed, all of their phones will automatically connect to the device.

Once cell phones are talking to the Stingray, the device scoops up digital information and uses it to help agents ferret out their target. Some Stingrays have the capability to capture actual content — texts or telephone conversations — while others act like eyes and ears that can guide police to the precise geographic location of a targeted suspect, even within a couple meters.

And it doesn't even require a warrant.

"You can operate it without having to involve the cell phone providers at all," Peter Scheer, executive director of the California First Amendment Coalition, told us. His organization helped a journalist obtain records about the Los Angeles Police Department's use of Stingrays.

"The service providers, while they don't stand as a major barrier, tend to insist on police having some kind of judicial authorization," Scheer said. "It has been an important check on police use of these technologies."

MANY AGENTS USING IT

The FBI initially refused to provide the documents, but after the ACLU filed suit, the U.S. Attorney for the Northern District of California finally released some information, including a particularly juicy set of internal emails documenting federal agents' use of these devices.

In one of the emails, Criminal Division Chief Miranda Kane wrote: "Our office has been working closely with the magistrate judges in an effort to address their collective concerns regarding whether a pen register is sufficient to authorize the use of law enforcement's WIT technology ... to locate an individual."

("WIT technology" is described as a box that simulates a cell tower and can be placed inside a van to help pinpoint an individual's location with some specificity.")

Kane added: "Many agents are still using [this] technology in the field although the pen register application does not make that explicit." In a clarifying email sent later on the same thread, Assistant U.S. Attorney Kyle Waldinger noted: "Just to be super clear, the agents may not use the term 'WIT' but rather may be using the term ... 'Stingray.'"

Kane's reference to a "pen register application" describes a request for court approval to use an investigative tactic that can trace the outgoing numbers dialed from a particular phone. While Stingrays can potentially sweep in hundreds of cell phone customers' information, pen-register wiretaps focus narrowly on the digits being punched in by one individual.

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