Even though the film was about the FBI, J. Edgar Hoover would not sanction it because Producer Edward Small refused to allow the FBI to interfere with production and review the film prior to its release.
Raymond Burr appears here as a villainous heavy early in his career. He acted in many noir and dramatic roles for over a decade before taking up the briefcase as TV attorney Perry Mason (1957).
After Radchek arrives in San Francisco, he gives the real address of the apartment where the filming took place to his contact there - a rarity in films even then.
The ship at Pier 36 that is seen as the destination of the delivery truck with Braun's painting is the S.S. Matsonia. It was built in Philadelphia in 1926 for the Matson Lines and was originally named the S.S. Malolo. It was designed for the tourist trade between Los Angeles, San Francisco and Hawaii. On 25 May 1927 she collided with a freighter in the Atlantic and sustained damage that was as severe as that sank the RMS Titanic, but she made it back to port due to her much-improved hull design and compartmentalization. Repaired, she then sailed to San Francisco to begin her service. In 1937 she was completely overhauled and all cabins were converted to first class - 693 of them - and she was renamed S.S. Matsonia. She served as a troop transport in WWII. Returned to commercial service in 1946, Matson sold her in 1948 to Home Lines (which later became Holland America Lines). After 50 years of service and a few more names, she was sold for scrap in Greece in 1977.
The subject of Braun's second painting is the famous La Consulat Restaurant at 18 Rue Norvins, Paris, France.