Police are investigating the slayings of two men in separate shootings an hour apart in Philadelphia Tuesday night.

Robbery is believed to be the motive in the West Philadelphia killing of Anthony Gibbs, 38, police said.

Officers responding to report of gunfire found Gibbs at 9:17 p.m. on the 100 block of North 57th Street with a bullet wound to the head.

Gibbs, who lived in Northeast Philadelphia's Bustleton section, was taken to the Hospital of the University Pennsylvania, where he died at 10:37 p.m., police said.

No arrests have been reported.

Investigators have not yet identified a possible motive in the shooting death of Lemuel Coleman, 23, on his front porch in North Philadelphia.

Police responding to a report of a person with a gun on the 2700 block of West Seltzer Street at 8:19 p.m. found Coleman shot multiple times in the head, torso and legs.

Taken to Temple University Hospital, Coleman died at 8:48 p.m., police said.