Pleins Feux Sur L'assassin (1961)

When a wealthy Uncle (Pierre Brasseur) dies, his body can't be found. This frustrates his surviving relatives because under French law since there is no body, they can't inherit for another 5 years! They decide to open their Uncle's historical castle to the public to make money but then people start dying one by one. The final survivor will inherit it all! Written by Pierre Boileau and Thomas Narcejac (DIABOLIQUE) and directed by Georges Franju (EYES WITHOUT A FACE). Franju enters Agatha Christie territory here, notably AND THEN THERE WERE NONE but clearly he isn't interested in the mystery so much as watching his characters deal with the pressure of trying to lead normal lives while their insulated world starts cracking. The audience is one up on the characters because we know where the Uncle's body is since we were shown at the beginning so it eliminates that as a mystery to us so we're primed to watch the protagonists under glass struggle away. The underscore is by Maurice Jarre. Among the suspects and victims: Jean Louis Trintignant, Marianne Koch, Dany Saval, Philippe Leroy, Jean Ozenne, Georges Rollin, Pascale Audret and Gerard Buhr.