Jean Sorel as Dr. George Dumurrier

Marisa Mell as Susan Dumurrier / Monica Weston

Elsa Martinelli as Jane Bleeker

Alberto de Mendoza as Henry Dumurrier

John Ireland as Inspector Wald

Riccardo Cucciolla as Benjamin Wormser

Franco Balducci as Officer Loveday

Bill Vanders as Insurance Agent

Giuseppe Addobbati as Brent

Félix Dafauce as Royal Insurance Official

Jesús Puente as Sergeant Rodriguez

George Rigaud as Arthur Mitchell

Jean Sobieski as Larry

Faith Domergue as Marta

Lucio Fulci as Graphologist

Malisa Longo as Elizabeth O'Neill

Geoffrey Copleston as District Attorney

Raffaele Mottola as Governor

Bobby Rhodes as Prison Guard