According to the audio commentary by Imogen Sara Smith, production was shut down for a day and restarted after Steve Sekely was removed from the picture for creative differences, with Paul Henreid taking over. Sekely retained director credit for contractual reasons.
According to contemporary newspaper articles, Paul Henreid decided to produce this film himself, so that he could play a bad guy for once.
Gasoline was 25.5 cents per gallon. Adjusted for inflation, 25.5 cents in 1948 had the same buying power as $2.76 in August 2019. The national average cost for a gallon of gas in August 2019 was $2.60.
The failure of the original copyright holder to renew the film's copyright resulted in it falling into public domain, meaning that virtually anyone could duplicate and sell a VHS/DVD copy of the film. Therefore, many of the versions of this film available on the market are either severely (and usually badly) edited and/or of extremely poor quality, having been duped from second- or third-generation (or more) copies of the film.