- William Gargan
- Ellery Queen
- Margaret Lindsay
- Nikki Porter
- Charley Grapewin
- Inspector Richard Queen
- Gale Sondergaard
- Mrs. Van Dorn
- Gilbert Roland
- Paul Gillette
- Sig Ruman
- Heinrich - Spy Leader
- James Burke
- Police Sgt. Velie
- Ernst Deutsch
- Dr. Morse - Lido Club Physician
- Maurice Cass
- Mr. Calkus - Museum Owner
- Minor Watson
- Cmdr. Lang
- Felix Basch
- Helm - Lido Club Manager
- John Hamilton
- Bracken - The Police Commissioner
- James Seay
- Marine Sgt. Stevens
- Ludwig Donath
- Reece
- Dick Wessel
- The Big Sailor
- Billy Bletcher
- The Small Sailor
- Willy Castello
- Van Dorn Chauffeur
- Dorothy Granger
- Apartment Tenant
- Grace Hayle
- Overweight Woman
- William Newell
- Apartment Tenant
- Jack Perrin
- Marine
- Jack Rice
- Railway Ticket Agent
- Arthur Space
- Lido Club Desk Clerk
- Harry Strang
- Marine Corporal
- Fred 'Snowflake' Toones
- Train Porter
- Hans Heinrich von Twardowski
- Capt. Earhardt
