Here’s a movie I saw back in 2001.

A couple had a baby boy, but it ended getting switched with another baby. Years later, this boy turns out to be a creepy kid who exhibits weird behaviour; namely, whenever people die or disappear under mysterious circumstances, he draws pictures which appear to indicate what happened to them. In time, the parents learn the creepy kid isn’t their biological son; their real son lives in a foster home, 'cause the woman who was raising him – the actual mother of the creepy kid – is a violent psychopath who was committed.

Anyway, it turns out the creepy kid isn’t the villain of the story; it was his psychologist or something behind the murders, and the creepy kid just happened to witness him in the act. In the end, the parents take their biological son into their home to raise alongside the creepy kid, who still exhibits antisocial behaviour and will still probably grow up to be a sociopath.