CHICAGO — Chicago police are investigating a report of shots fired by an off-duty officer overnight.

Police responded to a call of shots fired just before 3 a.m. Tuesday on the 2800 block of West Grace. Upon arrival, a man — who sources say was an off-duty cop — told officers that he observed several individuals attempting to steal a catalytic converter from a parked vehicle.

One of the male offenders then pointed a firearm at the man after becoming aware that he was nearby.

According to police, the off-duty officer drew his firearm and shot at the offender. The offenders then entered multiple vehicles and fled the scene, police said.

The off-duty officer was not injured and was transported to a local hospital for chest pain.

No one is in custody and Area Five Detectives are investigating.