The Zodiac Killer attacked seven people in Northern California in a ten-month span and was never caught. He is unusual among unidentified killers in how much of the record comes from him: more than twenty letters, four ciphers, and a claim of thirty-seven victims that no investigator has ever accepted.
The first attack came on December 20, 1968, on Lake Herman Road outside Benicia. David Faraday, seventeen, and Betty Lou Jensen, sixteen, were parked at a turnout. Both were shot dead beside the car. On July 4, 1969, at Blue Rock Springs Park in Vallejo, he shot Darlene Ferrin, twenty-two, and Michael Mageau, nineteen, in a parked car. Ferrin died. Mageau survived five bullets and gave a description. Forty minutes later a man called Vallejo police from a phone booth, reported both shootings, and hung up.
On September 27, 1969, at Lake Berryessa, he approached Bryan Hartnell and Cecelia Shepard wearing a black hood with a crossed circle stitched on the chest. He tied them and stabbed them both, then wrote the dates of his previous attacks on the door of Hartnell's car. Shepard died two days later. Hartnell lived. On October 11 he got into Paul Stine's taxi in San Francisco, told him to drive to Presidio Heights, shot him in the head and cut away a piece of his shirt. Three teenagers watched from a window across the street and called police while it was happening. A patrol car passed the killer on foot minutes later and drove on, having been given a description of a black suspect by mistake.
On August 1, 1969, three Bay Area newspapers each received a letter with a third of a 408-symbol cipher and a demand that it run on the front page. Donald and Bette Harden, a Salinas schoolteacher and his wife, broke it within a week at their kitchen table. It said that killing people was the most thrilling experience of his life and that his victims would become his slaves in the afterlife. It did not give a name. The name came in the next letter, on August 7: This is the Zodiac speaking. The Stine murder was confirmed with the piece of bloodied shirt, posted to the San Francisco Chronicle. A 340-character cipher sent in November 1969 held out for fifty-one years and was solved in December 2020 by David Oranchak, Sam Blake and Jarl Van Eycke. It contained no identifying information either.
Thousands of suspects were investigated. The best known is Arthur Leigh Allen, a Vallejo man who owned a Zodiac-brand watch and whose behaviour drew persistent police interest, and whom Mageau identified from a photograph in 1991. Allen's handwriting did not match the letters and the partial DNA recovered from the envelopes did not match him either. He died in 1992. No other named suspect has come nearer.
Five people died and two survived. The higher figures the killer claimed have never been substantiated, and the several murders sometimes linked to him by writers, including the 1966 killing of Cheri Jo Bates in Riverside, are disputed. San Francisco police marked the case inactive in 2004 and reopened it in 2007. Vallejo, Napa County and Solano County have never closed theirs.