The suspect ran down the 1300 block of Hellerman Street, and the officer tried again to subdue him, this time with pepper spray, Small said. "This also had no effect," he said.
The suspect picked up the officer and body-slammed him into the concrete, Small said. The officer then pulled his gun and fired once, striking the suspect in the chest, Small said.
The suspect was taken to Aria Health-Torresdale Campus, where he was pronounced dead at 4:52 p.m.
The officer, 39, was taken to Einstein Medical Center to have a CAT scan performed on his head, Small said. The officer was likely to be admitted overnight.
The robbery victim's mobile phone and cash were recovered, Small said.
The suspect did not have a weapon, but used "brute strength," Small said.
The robbery victim was one of six witnesses being questioned by detectives, Small said.
The violent encounter was recorded on several private surveillance cameras in the commercial corridor, Small said. Police already had watched some of the video, and what they saw "justifies clearly the officer using deadly force," Small said.
The officer has been placed on administrative duty pending an Internal Affairs investigation.
The suspect had been arrested eight times on charges of assault, theft, rape, harassment, and firearms violations, police said.