The Diamond Wizard

While in London trying to nab several fugitives who stole a million dollars from a U.S. Treasury vault, American federal agent Dennison (Dennis O'Keefe) assists Scotland Yard Insp. McClaren (Philip Friend) in his search for a missing atomic scientist (Paul Hardtmuth). The detective duo discovers that the key to solving both cases may rest with the scientist's daughter (Margaret Sheridan) and her fascinating diamond.

• 
  Montgomery Tully
• 
  Dennis O'Keefe
• 
  Jim O'Connolly
• 
  Adele Reynolds

• 
  Dennis O'Keefe
  Joe Dennison
• 
  Margaret Sheridan
  Marline Miller
• 
  Philip Friend
  Insp. McClaren
• 
  Alan Wheatley
  Thompson Blake
• 
  Francis de Wolff
  Yeo
• 
  Eric Berry
  Hunziger
• 
  Gudrun Ure
  Sgt. Smith
• 
  Seymour Green
  Lascelles
• 
  Paul Hardtmuth
  Dr. Eric Miller
• 
  Colin Tapley
  Sir Stafford Beach
• 
  Michael Balfour
  Hoxie
• 
  Cyril Chamberlain
  Castle
• 
  Paul Carpenter
  Mickey Sweeney (uncredited)