Philadelphia police on Tuesday identified the officer who shot an allegedly armed suspect during a foot chase in the city's Olney section Saturday.

During the pursuit, Officer Brian Rosenbaum shot 20-year-old Rashaun Payne in the back as Payne was running with a handgun toward the officer's partner, police said.

Payne, of the 200 block of West Louden Street in Feltonville, was taken to Einstein Medical Center in critical condition and subsequently charged with a firearms violation, resisting arrest, and related offenses.

Rosenbaum, a 10-year veteran assigned to the 35th District, and his partner were investigating a maroon minivan illegally parked next to a fire hydrant at Fourth Street and Lindley Avenue just before 6 p.m. Saturday when Payne allegedly ran from the vehicle.

Rosenbaum caught up to Payne and pushed him into a parked car, causing Payne to fall. As Payne got back up, Rosenbaum saw that he was holding a handgun and ordered him to stop, police said.

Payne ignored the command and ran toward Rosenbaum's partner on Lindley. Police said Payne was shot in the back by Rosenbaum and fell to the ground, dropping his gun.

Police identified the firearm as a semiautomatic Smith & Wesson 9mm loaded with 12 rounds. Police also recovered narcotics from the scene.

Rosenbaum was placed on administrative duty pending a required Internal Affairs investigation.

bmoran@phillynews.com215-854-5983@RobertMoran215