Director De Toth was doing only his second feature for Columbia with "None Shall Escape" and the studio wanted him to use Paul Lukas, who had recently enjoyed a great success in a similar role with Watch on the Rhine (1943). De Toth wanted a lesser-known star and campaigned for Alexander Knox, whom he had seen on Broadway in Chekhov's "Three Sisters." When Knox was hired and was told who was directing, he objected that De Toth was unknown and insisted on Lewis Milestone. Harry Cohn reportedly berated Knox for his selfishness and ingratitude. According to De Toth, he and Knox ended up as friends, and worked together on subsequent films.
Producer Samuel Bischoff got the idea for this film after hearing President Roosevelt's declaration on August 21, 1942 that the Allies were gathering evidence of Nazi war crimes.
Director André De Toth had already seen the war in Europe up close. He was in Hungary shooting newsreels when war broke out on September 1, 1939. He was sent to cover the German invasion of Poland.
This movie came out 15 months before Hitler killed himself. In the 40's and 50's, Americans claimed to know nothing about the concentration camps until Patton's forces discovered them. This movie is empirical evidence that people knew.
Filmed over two years before the start of the Nuremburg Trials that began in November 1945. For a dramatic film about those trials, see Judgment at Nuremberg (1961).