Blood Song (1982)

Frankie Avalon is a psychotic killer who plays a wooden flute and escapes from a sanitarium.  Frankie was only a child when he saw his father kill his mother and then commit suicide.  The worst part is his father only taught him one song before he died, so Frankie plays the same thing over and over.  But good god, don't say anything about it unless you want to end up dead.

Crippled high school student Marion is having dreams in which she sees Frankie killing people.  After she runs across him in the woods burying a body, Frankie starts chasing her, but no one believes what she says due to her crazy dreams and the lack of a body.

Frankie's hair is always prefect and he looks the same as when he was in the beach movies twenty years earlier.