Victim... or killer?

Endless Night (1972)

Directed by Sidney Gilliat

Shiftless dreamer Michael Rogers fantasizes about a lifestyle above his means and marries a wealthy, young girl who just came of age. They hire a famous architect to build their dream home amidst a series of suspicious incidents. The spouse has dark intentions toward his naive, inexperienced bride. Secrets from his past and sinister ties to their house guest Greta lead to a terrible turn of unexpected events.