Medverkande
-
Bela LugosiDr. Melcher / Monsieur Colomb - Joan BarclayAlice Saunders
- Clayton MooreFBI Agent Richard 'Dick' Martin
- George PembrokeDr. Bill Saunders
- Robert FrazerAmos Hanlin
- Edward PeilPhilip Wallace
- Robert FiskeRyder
- Kenneth HarlanFBI Chief Colton
- William NighRegissör
- Jack DietzProducent
- Sam KatzmanProducent
- Harvey GatesFörfattare