Delusion on AllMovie

Slow-moving and low-key, this psychological thriller about killings in a large, dark mansion has a classic setting and characters: Meredith Stone (Patricia Pearcy) is the nurse who comes to care for the invalid Ivar Langrock (Joseph Cotten), and Gabriel (John Dukakis) is his grandson who comes to visit after spending some time in a commune. A face looking out of the window of a locked room provides a clue that there might be some additional characters involved in this drama. One by one, people at the house are clubbed to death -- and the mystery continues until the story behind that face is made known.