State police in Michigan have been secretly using hundreds of thousands of dollars' worth of cell site simulator equipment to locate and track cell phones since at least 2006, according to records obtained by the ACLU and ACLU of Michigan. And although the agency justified its initial purchase of the surveillance gear as "vital to the war on terrorism," the records show that the department used its cell site simulators in 128 run-of-the-mill investigations last year—not a single one of which was for terrorism. The records also highlight the continuing problem of excessive secrecy about use of this invasive tracking equipment.

Cell site simulators, commonly known as Stingrays, can precisely locate and track phones by mimicking cell phone towers and forcing phones in the area to transmit their unique identifying information. Because these devices raise serious privacy concerns, the ACLU has been tracking their purchase and use by law enforcement agencies across the country.

The records show that the State Police spent more than $200,000 in 2006 to purchase a Stingray, Kingfish, and related cellular tracking equipment. That purchase was paid for by a federal Department of Homeland Security grant. In a document justifying the purchase, MSP asserted, "This equipment will allow the State to track the physical location of a suspected terrorist who is using wireless communications as part of their operation." Yet, according to a January 2015 breakdown of one year's worth of Stingray deployments, that's not how the technology is being deployed. Out of 128 investigations where MSP used Stingrays in 2014, 42 were related to homicides, 30 for burglaries and robberies, 12 for assaults, 11 for missing persons, and the rest for a mix of offenses including drug crimes, obstructing police, and fraud. Not a single terrorism investigation among them.