Tracking Devices Were Removed From N.Y.P.D. Vehicles at Chief’s Request

Jillian Snider, a retired police officer who teaches at the John Jay College of Criminal Justice, said that the department made a big push to install the devices in all precinct vehicles around 2017, including unmarked units.

Officer safety was a key reason, Ms. Snider said. Department officials wanted the devices as a backup tool to find officers responding to large-scale emergencies or dangerous calls, she said.

“I cannot think of one valid reason to have an AVL removed,” Ms. Snider said.

Mr. Maddrey told officers he wanted the devices removed for security reasons, according to one of the people with knowledge of the investigation. That justification makes little sense, Ms. Snider said.

“If it’s for security reasons, you’d want your AVL even more because if you became unreachable for some reason, then you’d have that backup,” she said. “You’d want someone to know where you are.”