| Person | Type | Job | Role(s) |
|---|---|---|---|
 Carroll Clark | Crew | Art | Settings |
 Edgar Wallace | Crew | Writing | Story |
Garrett Fort | Crew | Writing | Screenplay |
 Irving Pichel | Crew | Directing | Director |
Joseph F. Biroc | Crew | Camera | Camera Operator |
Lucien N. Andriot | Crew | Crew | Cinematography |
Marion Dix | Crew | Writing | Screenplay |
 Max Steiner | Crew | Sound | Music Director |
 Merian C. Cooper | Crew | Production | Production Executive |
Philip Faulkner Jr. | Crew | Sound | Sound Recordist |
Ralph Block | Crew | Writing | Screenplay |
Shirley C. Burden | Crew | Production | Production Assistant |
 Van Nest Polglase | Crew | Art | Settings |
Walter Mayo | Crew | Directing | Assistant Director |
William Hamilton | Crew | Editing | Editor |
Charles Bohny | Crew | Camera | Assistant Camera |
 Dorothy Wilson | Cast | Actress | Patricia Merrick, also known as Mlle. Mystera |
 Dudley Digges | Cast | Actor | Horace Merrick |
 Ed Brady | Cast | Actor | Paddywagon Cop (uncredited) |
 Frank Reicher | Cast | Actor | Joe Valerie |
 Gertrude Hoffmann | Cast | Actress | Mattie (as Gertrude W. Hoffman) |
Irving Pichel | Cast | Actor | Police Radio Announcer (voice) (uncredited) |
 Jane Darwell | Cast | Actress | Mrs. Marble |
 Max Wagner | Cast | Actor | Policeman in Car (uncredited) |
 Oscar Apfel | Cast | Actor | Chief of Detectives John F. O'Hara |
 Pat O'Malley | Cast | Actor | Detective Brady (uncredited) |
 Stanley Blystone | Cast | Actor | Police Car Driver (uncredited) |
 Stuart Erwin | Cast | Actor | Dwight Wilson |
Ted Oliver | Cast | Police Desk Sergeant Hamilton (uncredited) | |
 Tom Brower | Cast | Actor | Detective Schultz (uncredited) |
 Warner Oland | Cast | Actor | Dr. Paul Cornelius |
| Person | Type | Job | Role(s) |
