The Zodiac Killer's reign of terror began in December 1968 with the murders of David Faraday and Betty Lou Jensen. Over the next few years, the killer claimed several more victims, including Darlene Ferrin and Michael Mageau, who survived the attack.

The Zodiac Killer's letters to the police were filled with cryptic messages and ciphers, some of which have never been solved. The killer also taunted police with phone calls, often threatening to kill more people if they were not caught.