Police identify the victim as Ahmir Jones.
It happened around 2:15 a.m. Tuesday on the 1700 block of Cecil B. Moore Avenue.
"I heard three gunshots which woke me up, and then the girlfriend of the man that was shot was just screaming," said Samantha Helstrom, who lives on the block.
Helstrom said she called 9-1-1. She said Jones' girlfriend banged on her door asking her and her roommates for help.
Police say, two men, at least one of whom was armed, approached the couple on the sidewalk and announced a robbery.
"They put both the male and female against the wall. They went through their pockets. They took the female's cellphone. And according to the female, for no reason, they fired a shot striking this 18-year-old victim in the chest," Philadelphia Chief Inspector Scott Small said.
Temple University senior Brian Margolies added, "It happened right below my apartment. It seems like there's nothing more the kid could have done, so it does it scares me, it scares me a lot."
Jones collapsed at the scene.
Officers found him unresponsive and took him to the hospital in extremely critical condition. Jones died of his injuries a short time later.
Small says the girlfriend was distraught, but was able to tell police what happened.
Police say they did not find any ballistic evidence from the scene.
Detectives are scouring nearby businesses to see if surveillance cameras picked up clues.
University officials tell Action News that Jones was not a Temple student.
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