Schizoid (1980)

Julie is an advice columnist for the city newspaper who begins to receive anonymous notes threatening murder and worse. At about the same time, female members of the group therapy session she attends are being stabbed, one by one, by an unknown assailant.

Is there a connection? If so, why do the notes talk about murder with a gun, while the murder victims are being stabbed? At first, the police, her ex-husband, her therapist and her friends all assure her that the notes are probably unrelated, and hoax; but with time, it becomes apparent that someone close to her is responsible. Is it her therapist, Pieter, who has sex with his patients just before they are murdered? Or Alison, Pieter's daughter, who resents Julie for Julie's romantic involvement with her father? Is it Julie's ex-husband, who never really wanted their divorce? Or maybe Gilbert, the eccentric building maintenance man whom many people believe is a little crazy anyway? Just about everyone around her seems mentally disturbed enough to be the culprit.