Baltimore County police have used controversial cell-phone tracking technology more than 600 times in the past five years, the department said for the first time Thursday.

The county bought "stingray" technology in February 2010 for $283,000 and upgraded it in March 2013, police spokesman Cpl. John Wachter said Thursday in response to questions from The Baltimore Sun.


A stingray device simulates a cell phone tower, allowing police to track phones. Privacy advocates have raised concerns that law enforcement agencies use the technology with little oversight. In a court hearing Wednesday, a Baltimore detective revealed that city police have used it more than 4,000 times since 2007.

Since Baltimore County's purchase, police there have used the technology 622 times, "for a wide range of purposes" that includes finding violent felons and endangered missing people, Wachter said.

Wachter and Baltimore County State's Attorney Scott Shellenberger said county police obtain court orders to use the device. Shellenberger said cell phone evidence is "powerful information that we obtain lawfully, that is being used to not only solve crime but also to convict people."

Until recently, the technology has been largely hidden from the public because of non-disclosure agreements with the FBI that agencies must sign to use the equipment.

Shellenberger acknowledged that his office also had a non-disclosure agreement with the FBI, but said the federal agency has recently begun allowing authorities to talk about the technology in general terms.

Critics call the technology invasive and have questioned whether the courts have enough oversight of its use.

Other police departments in the state that use the devices are Montgomery, Anne Arundel and Prince George's counties, according to the ACLU of Maryland.