Henri-Georges Clouzot	...	(Director)
Pierre Boileau, Thomas Narcejac	...	(Writer)
Simone Signoret	...	Nicole Horner
Véra Clouzot	...	Christina Delassalle (as Vera Clouzot)
Paul Meurisse	...	Michel Delassalle
Charles Vanel	...	Alfred Fichet, le commissaire
Jean Brochard	...	Plantiveau, le concierge
Thérèse Dorny	...	Mme. Herboux
Michel Serrault	...	M. Raymond, le surveillant
Georges Chamarat	...	Dr. Loisy
Robert Dalban	...	Le garagiste
Camille Guérini	...	Le photographe (as Camille Guerini)
Jacques Hilling	...	L'employé de la morgue
Jean Lefebvre	...	Le soldat
Aminda Montserrat	...	Madame Plantiveau
Jean Témerson	...	Le garçon d'hôtel (as Jean Temerson)
Jacques Varennes	...	M. Bridoux, professeur
Georges Poujouly	...	Soudieu, un élève
Yves-Marie Maurin	...	Moinet, une jeune Moynet
Noël Roquevert	...	M. Herboux
Pierre Larquey	...	M.Drain, professeur
Christian Brocard	...	Un homme à la morgue (uncredited)
Jean Clarieux	...	Le chauffeur (uncredited)
Henri Coutet	...	L'employé de la morgue (uncredited)
Johnny Hallyday	...	Un élève (uncredited)
Henri Humbert	...	Patard, le jeune Patard (uncredited)
Zappy Max	...	Lui-même - Voix radio (uncredited)
Madeleine Suffel	...	La dégraisseuse (uncredited)
Jimmy Urbain	...	Un élève (uncredited)
Georges Van Parys	...	Original Music Composer
Armand Thirard	...	Director of Photography
Madeleine Gug	...	Editor
Léon Barsacq	...	Art Direction
William Robert Sivel	...	Sound Designer
Jean Lallier	...	Camera Operator
Jeanne Witta	...	Script Supervisor
Robert Juillard	...	Camera Operator
Louis Née	...	Camera Operator
Jacques Robin	...	Camera Operator
René Masson	...	Additional Writing
Frédéric Grendel	...	Additional Writing
Carven	...	Costume Design
Simone Knapp	...	Hairstylist
Anatole Paris	...	Makeup Artist
Michel Romanoff	...	Assistant Director
Daniel Diot	...	first assistant camera
Léo Mirkine	...	Still Photographer

Summary: The wife and mistress of a sadistic boarding school headmaster plot to kill him. They drown him in the bathtub and dump the body in the school's filthy swimming pool... but when the pool is drained, the body has disappeared - and subsequent reported sightings of the headmaster slowly drive his 'killers' (and the audience) up the wall with almost unbearable suspense...