Evidence from a separate robbery may help investigators determine who was involved in the fatal shooting of 22-year-old Billy Schmidt, sources say.
Schmidt was shot and killed early Saturday morning in the 1900 block of Durfor Street, in what police described as an apparent robbery.
Police have released images of the two suspects.
Philadelphia police release images of suspects in killing of Penn State student
Surveillance video captured by nearby cameras appears to show the moments leading up to the shooting. In one video, a man can be seen throwing a cell phone. Seconds later, another man runs around a corner with Schmidt chasing him. The gunman then turns around and shoots Schmidt in the chest, just yards from his family's home around 1:30 a.m.
In video released by police, investigators said the suspects can be seen walking in the area of 20th Street from Ritner Street to Jackson Street before encountering Schmidt. They were also allegedly seen fleeing on foot in the area of 22nd & Porter streets after the shots were fired.
"You're going to be caught. It's just a matter of time," said Anthony Giordano, who lives nearby.
Schmidt's father said he later found the phone under a car and turned it over to police.
Family members said Schmidt had been returning from a nearby bar where he had been watching the NBA Finals with friends.
A memorial of candles, signs and flowers has continued to grow at the site.
Community members described Schmidt as a warm, outgoing young man whose kindness drew people in.
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"Billy Schmidt is everybody's son because he's an innocent victim. It could have been any of our children," said Ellen Murphy of Washington Township.
Friends said the large turnout at the vigil on Thursday reflected the impact Schmidt had on those around him.
"He was a kid that talked to everyone, and no one was too cool for Billy," said friend Liam McCusker.
"I just hope he's looking down to see how much everyone loves him," Schmidt's father, Bill Schmidt, said.
Schmidt will be laid to rest on Tuesday.
Police are asking anyone with information about the suspects to come forward.
A $20,000 reward is being offered for tips leading to an arrest and conviction.