RIVERSIDE (CBSLA.com) — Riverside County Sheriff’s are actively trying to recover a handgun they say was stolen Friday evening from a patrol car.

The theft took place inside a car parked outside a pizza restaurant at Van Buren Boulevard and Wood Road, said authorities.

The suspect remains at large.

Officials are checking security video from an array of businesses tying to put together a suspect description.

Authorities said the gun was stolen about 7 p.m. along with a jacket that was inside the patrol car. Officials confirm a deputy stopped for food but inadvertently left the car unlocked.

A passerby noticed someone inside the car and alerted the deputy.

The jacket was recovered nearby, reported CBS2 and KCAL9′s Suraya Fadel.

The handgun — described as a back-up weapon — is reportedly a semi-automatic.

Authorities said the suspect is believed to be a transient.