Gun violence ricocheted across Philadelphia Thursday night and early Friday, killing four men and injuring 11 others, including an off-duty city police lieutenant.

Robert Friel, 48, a 28-year veteran in the Third District, was shot in a leg inside a CVS store at 10th and Reed Streets about 6:45 a.m. when he went to assist a fellow officer in dealing with a suicidal man who was known to have weapons, police said. He was in stable condition Friday at Thomas Jefferson University Hospital.

In the most recent killing, at 11:04 a.m. Friday, police found a 50-year-old man unresponsive and suffering from blunt force trauma to the head and face in the basement of a building in the 2600 block of East Ann Street in Port Richmond. The victim was pronounced dead at the scene, police said.

At 11:18 p.m. Thursday, officers responded to 5200 Wayne Ave. in Germantown for a report of a person with a gun, and found an unresponsive 37-year-old man in the driver’s seat of a crashed white Dodge. He had been shot in the head and died at Temple University Hospital at 11:35 p.m.

About a half-hour later, at 11:56, officers were called to the 1600 block of South Conestoga Street in West Philadelphia, where they found an 18-year-old man in the street unconscious. He had been shot and later died at Penn Presbyterian Medical Center.

In the earliest killing, officers responded to the 300 block of North 55th Street in West Philadelphia, where they found multiple shooting victims at 10:44 p.m. A 29-year-old man had been shot in the left side of the chest and later died at Penn Presbyterian. Three men who were shot in their legs, ages 30, 22, and 27, were admitted to the hospital in stable condition, police said.

Two males are sought in the quadruple shooting. One was described as 5-foot-10, stocky, and wearing a black sweat suit, hooded sweatshirt, and black mask. The other was described as 5′7″ to 5′8″, thin, wearing all black, with a black hood on his head and a black mask.