NEW KENSINGTON, Pa. (AP) — Authorities are seeking a suspect in the fatal shooting of a rookie police officer.

Pennsylvania state police have issued an arrest warrant for 29-year-old Rahmael Sal Holt. He's accused of killing New Kensington Officer Brian Shaw during a traffic stop Friday night.

Authorities say the 25-year-old Shaw was shot in the chest while chasing Holt on foot. He was taken to a hospital, where he was pronounced dead.

Holt faces charges of murder and murder of a police officer.

Investigators say they know why the traffic stop occurred. But they won't provide further details, citing the ongoing investigation.

Shaw had served as a part-time officer in three other towns before joining the New Kensington force full time in June.

New Kensington is about 18 miles (29 kilometers) northeast of Pittsburgh.