Ray Stricklyn noted in his autobiography "Angels & Demons" that co-star Norma Eberhardt had one blue eye and one brown eye. If you look carefully at a few of her close-ups, even in this black-and-white film, you can notice the difference.
The Hammer classic "Horror of Dracula" was issued shortly after this low budget black and white feature, quickly forgotten in the wake of Christopher Lee's successful portrayal in vivid color.
Francis Lederer mentioned in a 1993 interview with Skip E. Lowe that he hated making this film and his agent had tricked him into doing it.
It's interesting that Gerald Fried, who previously scored Stanley Kubrick Paths of Glory (1957), did the score for this film and used "Dies Irae" throughout it, which later was used as the theme in Kubrick's The Shining (1980).