In one scene Oliver Reed was supposed to unlock Fabio Testi's handcuffs and drag him out of the car but Oliver couldn't get the small keys to fit in the cuffs. After 3 takes he got frustrated and threw the keys which happened to fall into a sewer drain. Fabio was left in handcuffs for two hours before more keys could be located.
Director Sergio Sollima said in an interview that Oliver Reed was good to work with until 2 or 3 in the afternoon because then his alcoholism would become difficult to work with. Star Fabio Testi also expressed that it was both exciting and difficult to work with Reed due to his alcoholism, and he would become violent on the set on many occasions.
According to a DVD special feature, the crew were told that Oliver Reed would be finishing his scenes on a day four days after what would actually be his last day of filming. This was because crew on the film apparently had scores to settle with him and the false finish date was given to protect him.
Both American radio spots and the main release movie poster for this film compared it with the Charles Bronson movie Death Wish (1974). The radio slogans and print tag-lines boasted that this movie made Charles Bronson's Death Wish (1974) "look like wishful thinking".