What is this movie

I saw this movie in the early nineties, and it remains the only movie I haven’t been able to track down using the IMDb. What I remember about it is that it took place in Niagara Falls, and involved this high school kid who thinks he saw his Mom’s new husband rape and kill someone under a waterfall, but all he saw was a tattoo on his ass, not the guy’s face. Turns out he was right, there’s some other guy that lives in the house with them and is friends of the new husband, and he’s involved somehow, and the kid was looking at him in his room b/c he thought he saw the tattoo, and gets caught, so they all think he’s gay. Towards the end, the bad husband tries to kill the kid by shooting through the window of his car, or something. Also, there’s this weird girl who starts hanging out with him and believes that he saw something. I originally thought Brian Keith was the new husband, but I can’t find it searching on his movies in the IMDb, so it must have been some guy that looked like him. Also nothing when I search IMDb on location = Niagara Falls. I saw it late at night on Showtime, so it may not be very mainstream. It’s been killing me that I can’t find out what this movie was.

Anybody remember this one?

Oops, I meant David Keith, not Brian Keith…