An off-duty police officer is recovering from a gunshot wound to his shoulder after he was attacked early this morning near his Overbrook Park home, according to police.

Ofc. Robert Penn, 46, was coming home from his shift when he got out of his car on Brentwood Road near Haverford Avenue around 12:09 a.m. and was approached by a man who mumbled something unclear and then shot Penn once in his right shoulder and ran down a nearby alley, said Philadelphia Police spokesman Lt. John Stanford.

The bullet exited through Penn's back and the officer was taken to the Hospital of the University of Pennsylvania, where he was listed in stable condition, according to police.

Penn is a married father of two children - a 17-year-old son and a 9-year-old daughter - and he has served 24 years on the force. He is currently assigned to the 16th District, which is headquartered at 39th Street and Lancaster Avenue in Powelton, though he was previously assigned to the 19th District, which is headquartered at 61st and Thompson streets in West Philadelphia and covers the area where he lives. While he was at the 19th District, Penn worked on the narcotics enforcement team, according to a source.

The suspect is described as a 5-foot-8 black man who was wearing a black jacket, black hat and black pants at the time of the shooting.

The department has not yet released a possible motive for the attack nor have they identified a suspect. According to reports, Deputy Commissioner Richard Ross said Penn was in plain clothes at the time of the shooting, so it's not clear if the assailant knew Penn was a cop.

Anyone with information on the case is asked to call police at 215-686-8477.

Staffer Morgan Zalot contributed to this report.