Hidden device in a personal car

The client parked in the center and went on business for a few hours. When he returned, the car was not there. It was towed to a towing yard.
For two days, the client tried to take the car back, but the employees at the parking lot refused, explaining that the car was parked and it could not be moved out until the keys to other cars were found.
The client became suspicious and came to us for an inspection.
The inspection revealed a GPS tracker.