The Psychopath (1966)

Inspector Holloway (Patrick Wymark) 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 (Margaret Johnston), whose house is overcrowded with a doll collection. Her pale, wide-eyed, neurotic son Mark (Sir John Standing) becomes the prime suspect, but are the Police mistaken? The daughter of one of the victims discovers the shocking truth.

Source: IMDB