Directed by
| Mario Bava | ||
Writing Credits
| Mario di Nardo | ... | (story and screenplay) |
| Mario Bava | ... | (additional material) (uncredited) |
| Agatha Christie | ... | (novel) (uncredited) |
Cast (in credits order) complete, awaiting verification
| William Berger | ... | Professore Fritz Farrell / Professor Gerry Farrell | |
| Ira von Fürstenberg | ... | Trudy Farrell (as Ira Furstenberg) | |
| Edwige Fenech | ... | Marie Chaney | |
| Howard Ross | ... | Jack Davidson | |
| Helena Ronee | ... | Peggy Davidson (as Helena Ronée) | |
 |
Teodoro Corrà | ... | George Stark (as Teodoro Corrá) |
| Ely Galleani | ... | Isabel (as Justine Gall) | |
| Edith Meloni | ... | Jill Stark | |
| Mauro Bosco | ... | Jacques / Charles | |
| Maurice Poli | ... | Nick Chaney | |
Produced by
| Luigi Alessi | ... | producer |
| Mario Bregni | ... | producer (uncredited) |
| Pietro Bregni | ... | producer (uncredited) |
| Ira von Fürstenberg | ... | executive producer (uncredited) |
Music by
| Piero Umiliani | ||
Cinematography by
| Antonio Rinaldi | ... | director of photography |
| Mario Bava | ... | (uncredited) |
Editing by
| Mario Bava | ||
Production Design by
| Giuseppe Aldrovandi | ||
Set Decoration by
| Giulia Mafai | ... | (as Giuliana Mafai) |
Costume Design by
| Giulia Mafai | ... | (as Giuliana Mafai) |
Makeup Department
| Orietta Melaranci | ... | makeup artist (as Oretta Melaranci) |
Production Management
| Luigi Alessi | ... | production manager |
| Alfonso Cucci | ... | assistant production manager |
| Adolfo Martello | ... | assistant production manager (as Rudolfo Martello) |
Second Unit Director or Assistant Director
| Mario Bianchi | ... | assistant director |
Art Department
| Rodolfo Gasparri | ... | poster designer |
| Giulia Mafai | ... | set dresser (as Giuliana Mafai) |
| Mario Bava | ... | paintings (uncredited) |
Sound Department
| Leopoldo Rosi | ... | sound |
Special Effects by
| Mario Bava | ... | matte paintings (uncredited) / special effects (uncredited) |
Visual Effects by
| Ettore Catalucci | ... | optical effects (as E. Catalucci) |
Camera and Electrical Department
| Gianlorenzo Battaglia | ... | assistant camera (as Lorenzo Battaglia) |
| Armando Pietrangeli | ... | still photographer |
| Emilio Varriano | ... | camera operator |
Costume and Wardrobe Department
| Roberto Ranucci | ... | assistant costumes designer |
Editorial Department
| Liliana Serra | ... | assistant editor |
Music Department
| Piero Umiliani | ... | musical director |
| Alessandro Alessandroni | ... | musician: guitar (uncredited) / musician: sitar (uncredited) |
Script and Continuity Department
| Marisa Agostini | ... | continuity |
Additional Crew
| Ettore Catalucci | ... | laboratory director: S.P.E.S. (as E. Catalucci) |
| Franco Tupini | ... | production secretary |
| Ferruccio Amendola | ... | voice dubbing: Mauro Bosco (uncredited) |
| Luciano De Ambrosis | ... | voice dubbing: Maurice Poli (uncredited) |
| Manlio De Angelis | ... | voice dubbing: William Berger (uncredited) |
| Arturo Dominici | ... | voice dubbing (uncredited) |
| Micaela Esdra | ... | voice dubbing: Ely Galleani (uncredited) |
| Vittoria Febbi | ... | voice dubbing: Helena Ronee (uncredited) |
| Michele Gammino | ... | voice dubbing: Howard Ross (uncredited) |
| Flaminia Jandolo | ... | voice dubbing: Edith Meloni (uncredited) |
| Melina Martello | ... | voice dubbing: Edwige Fenech (uncredited) |
| Ted Rusoff | ... | voice dubbing (US version) (uncredited) |
| Rita Savagnone | ... | voice dubbing: Ira von Fürstenberg (uncredited) |
| Robert Sommer | ... | voice dubbing (US version) (uncredited) |
| Sergio Tedesco | ... | voice dubbing: Teodoro Corrà (uncredited) |
| Renato Turi | ... | voice dubbing (uncredited) |
