Dirty Harry local and federal police committing offences and overstepping their authority by entrapment and obstruction of justice. Author McGilligan, argued that America needed a hero, a winner at a time when the authorities were losing the battle against crime. The box-office success of "Dirty Harry" led to the production of four sequels. In the 2007 film "Zodiac", also set in San Francisco and inspired by the Zodiac Killer, cartoonist Robert Graysmith approaches police detective Dave Toschi at the cinema, where he is watching "Dirty Harry" with his wife. When Graysmith tells Toschi he is going to catch the Zodiac killer, Toschi
Dirty Harry earlier encounter, Callahan does have one remaining bullet, with which he kills Scorpio when the latter goes for his gun. Callahan takes out his inspector's badge and throws it into the water before walking away. The script, titled "Dead Right", by the husband-and-wife team of Harry Julian Fink and Rita M. Fink, was originally about a hard-edged New York City police inspector, Harry Callahan, who is determined to stop Travis, a serial killer, even if he has to skirt the law and accepted standards of policing, blurring the distinction between criminal and cop, to address the question as to how