Family and friends have identified the victim to Action News as Shaquille Abraham.
Police say the call first came in at 10:22 a.m. Monday from a second floor apartment in the home at 9418 Fairgreen Lane.
Action News has learned the caller was a woman, believed to be the victim's girlfriend, who said she was hiding in a closet and believed someone had been shot.
Officers arrived to find Abraham shot once in the chest. Medics pronounced him dead at the scene.
Relatives tell Action News Abraham lived in the apartment with his mother and younger sister.
Neighbors say he grew up on the block and was well-known in the neighborhood. Family and friends said Abraham had no enemies and they have no idea who would target him like this.
"He was a great kid. Nobody has ever had problems with him," said neighbor Bee Pascarella.
"It's heartbreaking. I just got done work and my wife called me and said 'Shaquille got shot,' and I'm like 'What?" said Marc Pascarella.
Neighbors said Abraham was in the process of moving out of the apartment he grew up in and into an apartment of his own.
"He was waiting for the electric to be turned on today," said Bee Pascarella.
It was an emotional scene in the neighborhood as Abraham's mother and two older sisters arrived and learned of his death. His mother was taken away in an ambulance after collapsing.
The police are scouring the area looking for video surveillance that may help them identify the gunman.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.