Knowing the Producer and some cast members, you all likely did not know the main reason the Movie was made was to try and catch the Zodiak. There was a whole lot going on behind the scenes to scheme a plan where the Zodiak would come to see a Movie about himself. If he came, and was discovered, eventually arrested, The Movie Caught the Killer. So despite the poor reviews,what a thrill it would have been! Had a Movie caught a Killer, more folks would see it. Leading to more Movie productions. There could have been a Movie made about the methods developed to "catch" The Zodiak. Would you go see a film which led to the arrest of a Killer?
Review of The Zodiac Killer
