Sisters (1973, Brian De Palma)

Man and woman are contestants on game show, go back to her place after. She argues with her ex-husband in the evening, her “sister” in the morning, then her “sister” kills the man with a big knife. Neighbor Reporter sees the killing, bring the cops, they don’t believe her. She hires private eye, then investigates on her own. Finds out woman had siamese twin who died. Gets trapped, brainwashed at woman’s ex-husband’s suspicious psychiatric house, then twin kills doctor/ex-husband. Cops now believe brainwashed reporter, but she won’t help them anymore, only repeats that there was no body because there was no murder.

Amazing that in such a hitchcock-referential movie, IMDB and I can only think of three direct sources:
Rear Window, for the obsessive voyeurism
Rope, for the body in the couch that everyone walks around and sits upon
Psycho for the killing the “main character” 30 minutes in and switching focus to someone new, and for all the psycho-babble.
I guess Sisters just intensifies the sources, makes you all-too-aware of the references if you’ve seen the original movies. Strange then that Sisters itself is getting a remake.

Best visual gag: the cake decorator tool, which in close-up looks like a long dagger dripping blood.

Has that extreme-70’s-interiors look and red red fake blood of the early David Cronenberg movies sometimes. Cronenberg must’ve seen this at some point before making Dead Ringers.

Love the Bernard Herrmann score, love the split screen scenes. Movie’s far from a perfect thriller, but it’s definitely satisfying. Great, great ending (private eye on phone pole still watching the couch at a train station).