Police responded to the unit block of South Broad Street around 9:30 p.m. Tuesday.
When they arrived, officers found two gunshot victims and at least six shell casings at the scene.
According to the Salem County Prosecutor's Office, Juniel Feliciano-Lopez, 24, was the victim of a homicide after suffering multiple gunshot wounds.
The suspect was identified as Henry Kivelier Montero Jr., 23, of Philadelphia, officials said.
Montero died of a single self-inflicted gunshot wound at the scene.
The shooting is believed to have taken place after an argument that began between the two men on March 30, investigators said.
No other details about the victims have been released.