I'm trying to find a movie by this desctiption: It's about a man who kills his wife and stages it as a drowning in the bathtub. His son knows about it and he then kills everyone that gets close to his sone and ultimately a teacher I believe. I also think he was schizophrenic. Any help? Someone thought it was Robin Williams but I'm not sure.

Hide and Seek?

In Hide and Seek, Robert DeNiro's character had a daughter (played by Dakota Fanning), not a son. He was, however, schizophrenic and he killed his girlfriend, Elizabeth Shue. He did try to kill his former colleague/little girl's therapist, but wasn't able to. So I'm not sure ddjerry is describing Hide and Seek :o)