The working titles of this film were Now It Can Be Told, Private Line to Berchtesgaden and Hamburg Seven, Seven, Seven. After the opening credits, a written prologue reads: "This story is adapted from cases in the espionage files of the Federal Bureau of Investigation. Produced with the F.B.I.'s complete cooperation, it could not be made public until the first atomic bomb was dropped on Japan. The scenes in this picture were photographed in the localities of the incidents depicted--Washington, New York, and their vicinities; wherever possible, in the actual place the original incident occurred. With the exception of the leading players, all F.B.I. personnel in the picture are members of the Federal Bureau of Investigation."
       Numerous contemporary sources note that J. Edgar Hoover gave approval for the film's production, and a 13 Sep 1945 NYT article reported that "one of Mr. Hoover's three principal assistants supervised the production to assure its authenticity." Hoover appears briefly at the beginning of the picture, which contains shots of his office and the Bureau's headquarters. According to a studio press release, the Bureau's cooperation included providing the production crew with a special surveillance vehicle from which they could film street scenes on location in New York City without attracting a crowd. A studio press release announced that before filming began, actors Lloyd Nolan and William Eythe spent a week at the F.B.I. Academy in Quantico, VA, where they attended classes with student agents and underwent basic physical training.
       As noted in the film's prologue, the picture was largely shot on location in New York City, Long Island and Washington, D.C. and contains much documentary footage, shot for this film, of federal agents at work in the Bureau's headquarters. The Bureau's fingerprint department is shown, as well as numerous scientific methods of analyzing evidence. The footage of employees entering and exiting the German Embassy in Washington, D.C. was also taken from Bureau photographic files. According to information in studio records, the Appleton laboratory scenes were shot at the Nassau Plant in Great Neck, Long Island. The plant was a top-secret war defense laboratory, and the film crew and cast had to be cleared by military authorities. The Time review noted that some sequences were shot at the California Institute of Technology. Footage of Hamburg, Germany, was taken from a film entitled City of Hamburg, which was in the possession of the U.S. Office of Alien Property Custodian, which regulated German-owned pictures located in the U.S. during the war.
       According to information in the Twentieth Century-Fox Produced Scripts Collection and the Records of the Legal Department, both located at the UCLA Arts--Special Collections Library, this film was largely inspired by the F.B.I's 1941 arrest of thirty-three German and German-American spies. The spy ring, which was based in New York City, had been responsible for selling information about Norden bombsight, a valuable American military secret to Germany. Other military and defense secrets were sent to Germany by the spies, among whom Frederick Joubert Duquesne was the most famous. Duquesne had been a professional spy for over forty years at the time of his arrest. According to the studio records, Duquesne was the inspiration for "Col. Hammersohn" in the film. For additional information on Duquesne, please see the entry below for Unseen Enemy. "Bill Dietrich" was based on William G. Sebold, a German-born, American citizen who infiltrated the spy ring with the aid of the F.B.I. and set up a shortwave radio station, as Dietrich does in the picture. Another spy convicted in the case, artist's model and socialite Lilly Stein, was the inspiration for "Elsa Gebhardt" (but not for "Mr. Christopher"). Hermann Lang, who memorized details of the Norden bombsight, was the inspiration for "Charles Ogden Roper." All thirty-three of the spies were convicted of espionage and failure to declare themselves as foreign agents. Duquesne was sentenced to eighteen years, Stein received a sentence of ten years and Lang received a sentence of eighteen years.
       Other F.B.I. cases were used in the film, and the script files reveal that as late as 2 Apr 1945, the name of the atomic bomb was not allowed to be printed in the studio's copy of the screenplay "until release from proper authority can be obtained." According to an 18 Aug 1945 LAT news item, if the atomic bomb had not been used by the U.S. during World War II, "the story of espionage and the work of the F.B.I. would have been given a different motivation before the picture was released." According to a 14 Aug 1945 HR news item, studio executives decided not to mention the atomic bomb in its advertising because they felt "the picture is too good to be tied into such exploitation."
       The story records reveal that the role of "Elsa Gebhardt/Mr. Christopher" was originally to be played by a man, who would pretend to be a woman. Notes for a 9 Jan 1945 conference with production chief Darryl F. Zanuck report that Zanuck wanted Christopher to be "the one who is least suspected by the audience. Elsa should be Christopher--a man who poses as a woman. A German fairy. We want to cast a very good actor in this part--maybe someone from the stage, so that the audience will think it is a woman." In the finished picture, however, Elsa is a woman who impersonates a man. According to information in the legal records, Kurt Katch was originally signed to play "Col. Felix Strassen," and Charles Wallis was signed to play "Mr. X" and Fritz Pollard was signed to play "Julius." The latter two characters do not appear in the finished film. The picture marked the screen debuts of actors Vincent Gardenia, E. G. Marshall and Bruno Wick, and the American film debut of French actress Lydia St. Clair.
       The House on 92nd Street, which garnered excellent reviews, received an Academy Award nomination for Charles G. Booth's original story. The picture was one of several semi-documentary, dramatic films produced by noted documentary filmmaker Louis de Rochemont, who created "The March of Time" newsreels in 1934. Other pictures directed by de Rochemont, which contained a similar blend of fact, real people, actors and fiction were 13 Rue Madeleine, which was based on O.S.S. case files, and Boomerang. On 12 Oct 1945, William Eythe, Lloyd Nolan and Signe Hasso appeared in a radio version of the film, broadcast on the This Is Your FBI program. In Apr 1965, DV announced that de Rochemont had obtained screen rights to an espionage novel entitled The House on 93rd Street, but a film based on that book was not made.