Three people were killed in Philadelphia, including a suspected robber gunned down by an off-duty police officer, and three others were wounded in overnight violence this weekend.

At about 1:50 a.m. Sunday, a Philadelphia police officer, going home after working a late shift in the 19th District, was confronted by two men after exiting his personal car in the 5800 block of Webster Street in the Cobbs Creek section of West Philadelphia, police said.

According to police, the two men announced a robbery and one of them put a gun to the officer's chest. The officer then shot one of the robbers with his off-duty handgun. The other robber fired at least one shot at the officer while fleeing on foot.

The wounded man was taken to the Hospital of the University of Pennsylvania where he was pronounced dead a short time later, police said.

Police were looking for a man about 18 to 20 years old, about 5 feet, 7 inches tall, wearing a tan hooded shirt.

In the city's Logan section, two people were killed late Saturday night in shootings police think were related.

A 35-year-old man was shot in the head and the abdomen in the 4900 block of North 11th Street at about 11:36 p.m., police said. The man was taken to Albert Einstein Medical Center where he was pronounced dead at 12:09 a.m.

At about 11:40 p.m. Saturday, a 17-year-old male was shot in thigh about two blocks away, in the 4800 block of Warnock Street, police said. He was taken to Einstein Medical Center and pronounced dead at 12:37 a.m., police said.

Three men were wounded by gunfire in an incident late Saturday night in Northeast Philadelphia.

Police said at about 11:45 p.m. Saturday in the 5800 block of Oxford Avenue, a 26-year-old man was shot in both legs, another man, 20, was shot in the hip and a third man suffered a graze wound to the right leg.

All three were listed in stable condition at Aria Health-Frankford Campus, police said. All of the shootings remained under investigation Sunday.

Contact staff writer Vernon Clark at 215-854-5717 or vclark@phillynews.com.