Video from nearby stores showed the shooter coming up from behind the two men and firing, then fleeing west on Venango and north on Eighth Street, continuing to fire as he ran.
Police recovered 22 shell casings from that shooting and 23 more from a similar encounter a week later, near Seventh and Clearfield Avenue, where two men were shot and a third was wounded by flying debris. Police ballistics experts concluded that the same gun was used in both shootings.
"It's of great urgency that we get this individual off the street," Homicide Capt. James Clark said Friday. "We have someone with this type of firepower just firing down the street. . . .. We've already had one person killed and three others shot. Quite frankly, we could have a lot more killed."
He asked anyone with knowledge of either shooting to call the Homicide Unit at 215-686-3334 or -3335.
"We really need the public's help," Clark said. "Call Homicide, give us a name, give us anything. We need to get him off the street as quickly as possible."
Police played video of the two shootings at a news conference Friday afternoon at Police Headquarters, but there were no clear images of the gunman's face.
"This is what you see when you have weapons like this out on the street," said Police Commissioner Charles H. Ramsey. "You think you're looking at Iraq instead of Philadelphia. . . . Anybody could have been walking down the street and been struck by one of those bullets."
Lt. Joseph Walsh of the police firearms identification unit said the gun was probably made in Romania, Hungary, or China as a replica of the original Russian AK-47, openly sold in gun shops or at gun shows for anywhere from $700 to $1,500.
U.S. gun manufacturers sell similar weapons, but they're less commonly seen because they're more expensive, Walsh said.
"You can't buy one of these weapons now without a waiting period," Ramsey said. "Not because of a background check, but because they're buying them faster than they can manufacture and sell them. It's insane.
"But that's a different issue," Ramsey continued, repeating his plea for public help in finding the shooter. "We've got to find a guy who's out there right now with an AK-47 firing at people in the street."
Contact Bob Warner at 215-854-5885 or firstname.lastname@example.org.