Charlotte prosecutors say police didn’t violate state laws with surveillance technology that allows authorities to scan an area for a cell phone used by a target suspect.

Multiple media organizations reported that the Mecklenburg County District Attorney’s Office determined local police properly turned over evidence to defense attorneys in nearly 150 cases in which officers used a tracking device called a StingRay. The device tricks cell phones into thinking it is a transmission tower so that data can be gathered.

Charlotte police and local agencies across the country have been using the technology since at least 2006 to collect serial numbers, locations and other information about nearby phones, laptop computers and tablets connected to cellular networks.

The FBI ordered cities not to disclose information about the equipment