An article in the 21 October 1962 edition of the Los Angeles Times called Elizabeth Montgomery "the most bruised actress in pictures". During this production she had a car door slammed on her hand and suffered contusions jumping from a pier onto a boat, among other injuries. Plus, she had to endure the filming of a brutal rape scene which ended up on the cutting room floor.
William Asher, the director of the movie, and Elizabeth Montgomery, the female lead, were married in the same month that the film was released in the United States, October 1963.
Coincidentally, Elizabeth Montgomery (Darien 'Dare' Guiness) and Elisha Cook Jr. (Undertaker) both died on May 18, 1995.
During the scene in which Hank Henry appears as the bus driver, his name can be seen on the billboard outside the Silver Slipper casino on the background.
In the opening scenes young Giordano is introduced to a man named Salvatore Guiliano. Guiliano was a real life Sicilian bandit who fought the fascists and was later murdered.