Clint Eastwood’s ‘Dirty Harry’ Is Based on This Unsettling True Story

It's 1971, Clint Eastwood introduces the world to one of his and Hollywood's most iconic characters, Inspector "Dirty" Harry Callahan in Don Siegel's action thriller Dirty Harry. Callahan is the definition of a loose cannon; a tough and cynical police officer who is not above pushing the limits of the law to bring in San Francisco's criminal element. Armed with a steely demeanor and a .44 Magnum, Callahan is on the hunt for a serial killer. In the real world, the SFPD is on the hunt for a serial killer as well: the infamous Zodiac Killer. Coincidence? Not in the least. Dirty Harry is, indeed, based on the true story of the SFPD's hunt for the elusive murderer.