The Justice Department has tightened restrictions for tracking cellphone signals in a move that officials say will improve transparency and protect the public from unwarranted invasions of privacy.
Henceforth the FBI and federal law-enforcement agencies will need a warrant supported by probable cause before using a so-called cell-site simulator, which can impersonate a cellphone tower by sending out signals that induce phones to respond with identifying information.
The move represents a win for privacy even though the warrant requirement doesn’t apply to state and local governments, which also use cell-site simulators to track suspects.
Transparency ftw! After public pressure and major press attention, DOJ will now require a warrant to use Stingrays. https://t.co/uThUGbBdrd
— EFF (@EFF) September 4, 2015
The devices, which are known variously as stingrays, dirtboxes or IMSI catchers (for International Mobile Subscriber Identity), are used widely for surveillance but have proved to be controversial because of their sweep and the secrecy that shrouds their use. Agents deploy the devices from cars and planes, which enable scanning across larger areas.
“Cell-site simulator technology has been instrumental in aiding law enforcement in a broad array of investigations, including kidnappings, fugitive investigations and complicated narcotics cases,” Deputy Attorney General Sally Quillan Yates said Thursday in a statement announcing the change. “This new policy ensures our protocols for this technology are consistent, well-managed and respectful of individuals’ privacy and civil liberties.”
The pivot by DOJ represents a departure from past practice, when law enforcement personnel had to certify merely that use of a cell-site simulator was relevant to an ongoing criminal investigation.
Under the revised guidelines, agents may not configure simulators to collect the contents of communications, including emails and text messages. Agents also must inform judges when applying for warrants that use of the device will capture information from cellphones in the vicinity that are not subject to the investigation, and that the simulator may disrupt service temporarily for all cellphones within reach of its signal. Officials also must detail to the court how they plan to delete data not associated with the device being targeted.
As is the case under the Fourth Amendment generally, federal officials can use a simulator without first obtaining a warrant in the event of so-called exigent circumstances or when the law does not require a warrant, in which instance agents must first obtain the OK of officials within DOJ.
The Guardian reported Friday that public defenders in Baltimore are examining more than 2,000 cases in which police used stingrays to gather evidence on suspects secretly. Prosecutors are obligated to disclose evidence against criminal defendants in the discovery phase of a criminal trial.