In Stuart Kaminsky's 1980 detective novel "Never Cross a Vampire" fictional shamus Toby Peters is hired by Bela Lugosi to investigate a series of death threats while the actor is working at Monogram on this film.
When a young woman's nerves commence to give way it is time she sought refuge in a strong man's arms.
Alice Saunders: I just ran into yours.
Monsieur Colomb: Mine might be dangerous.
At the 47:30 minute mark, a plane carrying Dick Martin is flying right to left across the screen, with a visible logo of "The Great Silver Fleet". At the 49:58 minute mark, the plane is now flying back to Washington, DC, and it is flying in the reverse direction, from left to right across the screen. The logo is indecipherable because it is actually the same shot seen earlier, just played back in reverse. All the letters are in mirror image.