River's Edge (1986)

A group of high-school friends must come to terms with the fact that one of them, Samson, killed another, Jamie. Reactions vary, as Layne is intent on protecting Samson and smuggling him out of the state, while others think it's best to go to the police. Matt's tough little brother also finds out about the body and no one knows quite how the police will learn about the murder or who will be blamed for it.