I want to say I was around 9 when I watched this movie so in the 90’s. I think a boy moved into a town. I want to say he was somewhat gothic looking with longer hair. He befriends the local bad teens and the leader I guess you’d call him had brown or blonde short hair. The thing that sticks out to me the most is they had a hangout cellar type place but they swam underwater to get to it. At the end I remember the gothic type guy swimming there and finding one of his friends murdered. Turns out it was the blondish hair guy that killed him. So they start fighting. Pretty positive the gothic looking guy won. This has drove me crazy for years!!