Obsessions (1969)

A painting falls off the wall in a rented room. The tenant, Nils, a doctorate student in medicine, looks through the little hole in the wall to what happens in his neighbors room. What he sees makes him forget his textbooks quickly. It's not just the sex that generates his curiosity; Soon he witnesses events that point towards a crime. As he becomes more and more entangled in the web of mystery, his fiancé, Marina, a young journalist, receives an assignment to report a murder case.