The cold-blooded “Scorpio” character was based on the real-life “Zodiac Killer” who used to taunt police and media with notes about his crimes (“Dirty Harry” Callahan was based on David Toschi, the chief investigator in the Zodiac case.)
Sometimes these movies inspire nut cases like this one.
Yes, and the bus kidnapping scene in Dirty Harry was inspired by the Zodiac threats against school buses in his letters.