Shakir Williams, 17, died Friday night in Hamilton, N.J., after a shooting at the fete, which was a birthday party for a 15-year-old girl, The Times of Trenton, N.J., reported Sunday. The party was held at the girl's home.
Police said they didn't initially find Williams because the home was so crowded with about 100 party-goers.
Four other people were injured in the altercation, which police said was caused by one shooter. The most seriously injured was a 17-year-old boy who was shot in the torso, arms, leg and groin. He was in critical but stable condition at Capital Health Regional Medical Center in Trenton Saturday, the newspaper said.
Two boys, aged 17 and 18, were shot in the legs and were treated and released from the hospital. A fourth boy, whose age was not reported, was shot in the calf and was released Saturday morning.
Police said they are questioning the birthday-girl's mother and stepfather -- who were upstairs during the party -- and her 23-year-old brother, who was taking cover charges from party-goers at the door.
"We are going to examine the underage drinking, but the priority right now is finding the shooter," said Mercer County First Assistant Prosecutor Angelo Onofri.
Police said they don't know the motive of the shooting, but several friends of Williams posted messages on Twitter after his death with the words "Up Top" and "801st," which are apparent references to gangs.