 | Fabio Testi als Enrico Rosseni |
 | Karin Baal als Herta Rosseni |
 | Cristina Galbó als Elizabeth Seccles (as Christine Galbo) |
 | Joachim Fuchsberger als Inspector Barth |
 | Günther Stoll als Professor Bascombe |
 | Claudia Butenuth als Brenda Pilchard |
 | Camille Keaton als Solange Beauregard |
 | Maria Monti als Mrs. Erickson |
 | Giancarlo Badessi als Mr. Erickson |
 | Pilar Castel als Janet Bryant |
 | Giovanna Di Bernardo als Helen Edmonds |
 | Vittorio Fanfoni als Enrico's Landlord |
| Marco Mariani als Father Webber |
 | Antonio Casale als Mr. Newton (as Antony Vernon) |
| Emilia Wolkowicz als Ruth Holden (as Emilia Wolkowich) |
| Daniele Micheletti als Mr. Bryant |
 | Antonio Anelli als Father Herbert |
 | Rainer Penkert als Mr. Leach, the Headmaster |
 | Carla Mancini als Susan, a Student |
 | Joe D'Amato als CID Officer w / The Daily Telegraph (uncredited) |
| John Gayford als Joseph Kane (uncredited) |
 | Alfonso Giganti als Man at Church (uncredited) |
 | Charles Howerton als Phillip Sullivan (voice) (uncredited) |
 | Maria Michi als Brenda's Mother (uncredited) |
 | Alfred Vohrer als Edgar Wallace (voice) (archive footage) (uncredited) |
| Joe Wadham als Policeman (uncredited) |
 | Augusta Di Vincenzi als Woman in church (uncredited) |
| Rory MacDonald als Phillip Sullivan (uncredited) |
| Massimo Dallamano | Director |
| Bruno Di Geronimo | Story |
| Massimo Dallamano | Story |
| Bruno Di Geronimo | Screenplay |
| Massimo Dallamano | Screenplay |
| Peter M. Thouet | Screenplay |
| Edgar Wallace | Novel |
| Fulvio Lucisano | Producer |
| Leo Pescarolo | Producer |
| Horst Wendlandt | Producer |
| Ennio Morricone | Original Music Composer |
| Joe D'Amato | Director of Photography |
| Antonio Siciliano | Editor |
| Clarissa Ambach | Editor |
| Gastone Carsetti | Art Direction |
| Elisa Gut | Costume Designer |
| Dante Trani | Makeup Artist |
| Enrico Melonari | Production Manager |
| Giuliano Principato | Unit Manager |
| Wolfgang Fritsche | Production Manager |
| Luigi Urbani | Assistant Art Director |
| Francesco Vernier | Sound |
| Peter Ruddis | Sound |
| Luigi Ciccarese | Camera Operator |
| Sesto Salino | Key Grip |
| Enzo Zocchi | Gaffer |
| Giuliano Corso | Assistant Editor |
| Bruno Nicolai | Music Director |
| Neil Robinson | Dialogue Coach |
| Luciano Vittori | Film Processor |
