Surveillance video obtained by CBS Philadelphia is dark and grainy, but you can make out Joel Johnson panhandling Monday evening between slow-moving traffic.

Just as the 28-year-old with special needs approached an unmarked police car with his arms outstretched, four shots were fired from inside, shattering the closed window and sending Johnson stumbling to the ground -- hit once in the torso.

"He approached the driver's side of the vehicle and the detective believed what he saw was a firearm in this man's hands," said Police Captain Sekou Kinebrew. "The detective believing that he was gonna be robbed or something was going to happen to him, induced his firearm."

Most don't know him by name, but nearly everyone we spoke to in this neighborhood knows of Johnson. They've seen him walking up and down this street asking for quarters, what he appears to have been doing when he was shot.

CBS News

"He's a handicapped kid, he don't bother nobody," said Johnson's brother, Hector Tirado. "He never walked with any weapons. You won't find a weapon on him. You'll find change, that's it."

A preliminary police investigation has not turned up any weapons. Neighbors say Johnson was harmless.

"He shot an innocent man because he was begging for a quarter," said one neighbor, gesturing with his hands. "Does this look like a gun to you? Answer my question man, does this look like a gun? This is a quarter."

The 29-year-old Philadelphia Detective Francis DiGiorgio is now on desk duty while an internal affairs investigation is conducted. Johnson is in critical, but stable condition.

