Kenneth Lee spotted the shotgun-toting man in the frightening Halloween mask in the parking lot of the drug store via security cameras.
"'I am armed. Do not come into the store,'" police said the pharmacist shouted repeatedly at the man as he came through the door and walked the 35 feet toward the counter.
Using an umbrella as a shield, the masked man vaulted the counter. Lee then fired several shots from a 9mm handgun, and when police arrived, they found the would-be robber dead on the floor.
The dead man, who had a distinctive tattoo of a large red-and-black wolf-faced monster on the right side of his torso, was not identified.
The alleged accomplice, who was found sitting in a stolen van, was identified as Kim Goldsboro, 54, of Camden. He has been charged with criminal homicide and related crimes, and was denied bail.
District Attorney David Heckler said, "There is no thought that we would prosecute the shooter in this case."
The drama unfolded just before 10 a.m. at the Pennsbury Pharmacy, on New Falls Road. Within two minutes of receiving the alarm, eight Falls Township police officers responded to the scene, said Lt. Henry Ward.
The store had just opened and no customers were inside at the time.
Ward said there have been a number of pharmacy robberies in the area recently.
Falls Township has a "bad" heroin problem, he said, adding that there had been 60 heroin deaths in the last four years.
"I don't think these guys were addicts," Ward said. "I think these guys were trying to get free product" to sell.
According to the store's Facebook page, the pharmacy opened kast Dec. 12. It had been a bicycle shop, neighbors said.
William Whittley, 71, planned to buy a pack of cigarettes at the drug store Friday morning and ended up making one of those split-second decisions that might have saved his life.
He happened to see the driver of the stolen van sitting in the parking lot.
"He looked strange," Whittley said.
Afraid the driver was about to pull out in front of him, Whittley said, he kept driving.
Less than a minute later, numerous police cars raced by him. It wasn't until he returned home, to the apartment complex across the street from the pharmacy, that he realized he could have walked in on the robbery.