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Jack Holt as Jack Hart aka Quinn |
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Constance Cummings as Julie Arnold |
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Boris Karloff as Jim Henderson |
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Claude King as Arnold |
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Bertha Mann as Nurse Edwards |
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Edward Van Sloan as Dr. August Steiner / Dr. Alec Munsell / Mr. X |
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Willard Robertson as Capt. E.J. Hawkes |
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Thomas E. Jackson as Agent Burke |
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Martha Mattox as Hotel Ansonia Maid |
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Jessie Arnold as Eastland Hospital Nurse |
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Harry Tenbrook as Man in Black / Henchman in Boat |
| Directing | John Francis Dillon | Director |
| Writing | Jo Swerling | Writer |
| Writing | Jo Swerling | Story |
| Directing | Edward Sloman | Assistant Director |
| Production | Harry Cohn | Producer |
| Camera | Ted Tetzlaff | Director of Photography |
| Editing | Otis Garrett | Editor |
