Producer AI Zimbalist wanted the film, which took place in the mid 1930s, to use cars manufactured in the forties. Director Don Siegel refused categorically.
The notorious "Lady in Red", who lured John Dillinger to the theater where he was shot and killed by the F.B.I., was named Anna Sage. Before production of this movie started, it was not known if Sage was still alive. She had been deported to her native Romania shortly after the incident, and the producers didn't want to use her real name without her permission for fear of being sued if she were indeed alive. So they named her "Ann Saper", which was the maiden name of director Don Siegel's mother.
Shot in seventeen days.
The film was made on a budget of just $175,000. At the end of the sixteenth day of filming, the producer told director Don Siegel that he would have to finish the film the following day, as the money would run out after that. Siegel executed no fewer than 55 separate set-ups the next day, enough to complete the film. He praised the cameraman, Hal Mohr, and described the experience as "horrendous".
Don Siegel described Mickey Rooney as "one of the most difficult people I ever worked with", but added that the actor had had a certain grudging respect for him because he was better at playing table-tennis.