Mystery Livewire Volt Vehicle GPS Tracker Found on Car

Hey there - A friend was having a radio installed on her car when the technician found a GPS tracker in her vehicle. She has no idea where it came from or who may have installed it & reached out to me for help. I suggested contacting the company (Brickhouse Security), but they said they were unable to provide any details for security reasons (LOL). Is the only option to contact police to obtain a subpoena? Any other advice? Thanks!