The Psychopath (1966)

Mother, may I go out to kill?

Inspector Holloway is investigating a series of brutal murders in which a doll of each victim is found at the scene. The dolls, as it turns out,were purchased by the crippled Mrs. Von Sturm, whose home is overcrowded with a doll collection. Her pale, wide-eyed, neurotic son is the prime suspect and the daughter of one of the victims discovers the shocking truth.