According to Terence Stamp, Wyler wouldn't let Samantha Eggar off the set during the day. He also wouldn't allow her to eat with anyone else during the lunch break. Stamp argues Wyler knew what he was doing, as the director whispered to him one day on set, "I know this looks cruel, but we're going to get a great performance out of her."
This film was cited by notorious serial killer Robert Berdella as a key inspiration for his crimes. Furthermore, serial killer Christopher Wilder aka the Beauty Queen Killer/Snapshot Killer had the book, on which this film is based, in his possession when killed by police in 1984. Moreover, Leonard Lake of the serial killer duo Leonard Lake and Charles Ng was obsessed with the book and seemed to have planned killing in part on the content of the book
According to the book "The Unkindest Cuts: The Scissors and the Cinema," William Wyler hated to cut this film and Kenneth More's entire co-starring role. Wyler said: "Some of the finest footage I ever shot wound up on the cutting room floor, including Kenneth's part."
Even though Samantha Eggar was unhappy with Terence Stamp's cold treatment of her during filming, she couldn't have known that he was simply following William Wyler's instructions and staying in character. Stamp later said, "All the guys had crushes on her, she was so beautiful... I had a crush on her, too, and I was friendly with her. But when we started the movie, Willy said, 'I don't want you to have anything to do with her.' He wanted me to withdraw any friendship. He didn't want her to have anywhere to go or anyone to talk to, except her coach. He didn't want her to be able to come to me in the evening and say, 'God, it's so awful.'"