Coaches, players and fans went through metal detectors with rumors of a death threat in the air.
American Christian School's Tyreke Evans was there when his 16-year-old cousin allegedly shot and killed another teenager last month, police said.
The shooting happened outside Evans aunt's house in Chester Township.
Tyreke was at the wheel as he left the house with his cousin, Jamar Evans, in the passenger seat and two friends, including a teammate in the rear seat.
According to a police report, Jamar Evans fired a shot at 19-year-old Marcus Reason and hit him in the chest.
Reason died and police are now worried that his friends are out for revenge.
Police said bad blood has been boiling between rival gangs and Tyreke may have gotten caught up in the middle of it.
Tyreke Evans is one of the most highly sought after high school basketball players in the country. He reportedly has narrowed down his choices to several colleges, including Villanova. Now there's concern that the colleges may lose interest with Tyreke caught up in a murder investigation.
Tyreke admits he knew his cousin did the shooting, but didn't come forward until three weeks later.
His lawyer said he is cooperating with investigators and has agreed to testify against his cousin.
Officials at American Christian School beefed up security and asked for additional police presence at Thursday night's game. No problems were reported.