According to Michael Winner's biography, Charles Bronson's alcoholic brother often visited the set to borrow money. Bronson was careful not to give him too much in case someone might kill him for it. He was later found dead in a cheap hotel room having been stabbed in the buttocks.
Producers Yoram Globus and Menahem Golan wanted Isaac Hayes to compose the music. Director Michael Winner refused and brought in Led Zeppelin guitarist Jimmy Page, who at the time was his next-door neighbor.
In an interview, Silvana Gallardo (who played the housekeeper) said the rape scene was "grueling" and took about six days to film. To prepare for the role, she talked to an actual rape victim. She also said the scene was mostly improvised and that the actors who played the criminals raping her would immediately cover her up with a robe or blanket when Michael Winner yelled "CUT!"
The film was shot on location and depicted actual "sleazy" areas of the city. Twenty off-duty men of the Los Angeles Police Department were hired to protect the film cast and crew from potential trouble.
Director Michael Winner once said of this movie: "From caveman days to today, there have always been violent times. You cannot say the Middle Ages weren't violent, before television or films. So where do you put the blame then - oil paintings and books?"