A 20-year-old Philadelphia man was arrested on assault, weapons and other charges yesterday after leading an off-duty police sergeant on a car chase during which shots were fired.

The man's 2-year-old child was in the car during the chase, and a shot was fired at the sergeant's car, police said.

Justin Ellis, of the 5700 block of Catharine Street, was apprehended on I-76 westbound, near Girard Avenue, where he had stopped. Police believe he threw the gun out of the car before stopping.

The sergeant's gun fired as he approached the car, but no one was injured, said Lt. Frank Vanore. Vanore was not sure whether the gun was discharged by accident or during a struggle.

Police and Internal Affairs officers are investigating, Vanore said.

The incident began about 10:30 a.m. in the 600 block of Franklin Place when a woman flagged down the sergeant and told him that a man was pointing a gun at a woman. It was Ellis' girlfriend, and the child belonged to the two of them, Vanore said.

When the sergeant tried to intervene, Ellis jumped in a car with the child and another passenger and fled. The sergeant was in the area to take someone to church, Vanore said.

- Susan Snyder