Part of what makes movies and TV shows inspired by the Zodiac Killer so terrifying — a list that includes 1971's The Zodiac Killer (pictured above), 2007's Zodiac, and 2005's The Zodiac, as well as an episode of American Horror Story — is that the perpetrator was never caught. He could still be out there and could strike at any moment. The killer is believed to have carried out at least five murders in the late '60s in San Francisco's Bay Area and gained notoriety for the cryptic messages he'd send local newspapers about his murders. One segment of a decoded note read, "I like killing people because it is so much fun." Every message concluded with a symbol of a circle with a cross through it, as well as a portion of a three-part cipher that he promised contained his identity.
