Kanei Daniel Avery was charged with aggravated assault and related charges following Friday's shooting in Chester, a city outside Philadelphia where violence was so pervasive last year the mayor declared a state of emergency and instituted a 9 p.m. curfew in some high-crime areas.
"A situation like this, you have to make a statement," said District Judge Spencer Seaton, according to The Philadelphia Inquirer. "These things have to stop. These families are hurting. The community is hurting as a whole."
Three others from nearby Claymont, Del., are also charged, including the 19-year-old woman who rented the hall for a party, authorities said.
No one has been charged in the deaths of Robel Laboy, 18, and David Johnson, 19. The cause of the shooting remains under investigation, but a neighborhood feud could be to blame, police said.
"Preliminarily, we're getting information that it was two different neighborhood groups within the city that had a history over the past year and a half," said Major John Gretsky told the Delaware County Daily Times.
Ballistics tests are being performed on multiple weapons recovered from the scene, but police have not determined their owners, Chester police said.
A hundred or more teens attended the party at the Minaret Temple No. 174 before shooting broke out shortly before 11:30 p.m. Friday.
Authorities said Avery was holding a silver handgun at the base of the temple's steps when he was tackled by a security guard. Police arrested him moments later.
Three other people were taken into custody in an office inside the temple. Carlisha Coleman, 19, had rented the hall for a birthday party that was advertised on Facebook. She and Gregory Santana, 23, and Derrick Hamlin, 18, were charged with assault, reckless endangerment and risking a catastrophe. They were held on $300,000 bail.
The district judge's office has no record of any of the four suspects having attorneys. Court records indicate none has requested a public defender.