Diabolique (1955)

"Diabolique" is a 1955 Thriller movie directed by Georges Van Parys and starring by Véra Clouzot, Simone Signoret. The cruel and abusive headmaster of a boarding school, Michel Delassalle, is murdered by an unlikely duo -- his meek wife and the mistress he brazenly flaunts. The women become increasingly unhinged by a series of odd occurrences after Delassalle's corpse mysteriously disappears.