PHILADELPHIA (CBS) – Police say an off-duty officer shot and killed one of two suspects during a robbery attempt at a pizza shop late Thursday night in the Lawndale section of Philadelphia.

This happened around 11:30 p.m. at Rising Sun Pizza on the 6900 block of Rising Sun Avenue.

Police say two men likely in their 20’s entered the store and announced a robbery while the officer — who was in plain clothes — was ordering takeout.

“He put the gun to the head of the off-duty detective and took $20 cash from the detective’s hand,” says Chief Inspector Scott Small. “He ordered the detective to lay on the floor while pointing the gun to his head.”

The suspects then tried to rob the store. That’s when, police say, the officer announced who he was and the suspects shot at him twice, but missed.

The officer returned fire, hitting one of the suspects in the side. That suspect dropped his gun and both suspects left the store, according to police.

The suspect that was struck collapsed in the parking lot and died.

Police identified the suspect as 33-year-old Andrew Ellerbe from Philadelphia.

“A second suspect fled the scene,” Small says. “It’s unknown whether or not he was struck by gunfire from the off-duty detective.”

The suspect that escaped the scene is described as a male in his 20’s, wearing a dark hooded sweatshirt, dark pants and a mask.

Harvey Venitsky, who lives above the pizza shop, questioned the wisdom of robbing this particular one:

“There’s always cops around. Unmarked, marked, bicycles, motorcycles and they’re always in there.”

No other injuries were reported, including to the owner of the pizza shop and an employee who were both in the store during the incident. The officer — who was shot at from point blank range — also was not hurt.

Police later discovered one of the robbers had brought a gun that fired blanks. The six shot revolver reportedly fired two “blank” cartridges and four live “blank” cartridges were still inside.

“The officer is extremely lucky that he was not shot,” Small says. “He is extremely lucky that he was not killed.”

Police now hope surveillance video in the store while help them find the suspect on the loose as an investigation continues.