The Cryptic Letters

Find out about the cryptic letters below.

The Zodiac’s Mysterious Letters

The Zodiac Killer’s letter-writing campaign began with the double murder of David Faraday and Betty Lou Jensen in 1968. Following the crime, the killer sent a letter to the Vallejo Times-Herald, claiming responsibility for the murders and including a cipher designed to be decoded. The letters exhibited a mix of arrogance, taunts, and a craving for public attention. The Zodiac Killer often referred to himself as the “Zodiac” and included cryptic symbols as his signature. One of the most eerie aspects of these letters was the Zodiac’s demand that they be published in the newspapers or else he would commit more murders.

The first major breakthrough in the case came with the deciphering of the 408-symbol cryptogram sent on July 31, 1969, to the San Francisco Chronicle. This cipher revealed a disturbing message but offered no concrete clues to the killer’s identity. The 340-symbol cryptogram, sent in a letter dated November 8, 1969, was particularly perplexing and remained unsolved for decades.

Cryptograms and Ciphers

Within these letters lay the true puzzle—the cryptograms and ciphers that the Zodiac Killer challenged the public to decode. These ciphers were designed to both taunt investigators and leave a lasting mark on the public psyche. The Zodiac Killer’s cryptograms were of particular interest to amateur codebreakers and professional cryptanalysts alike. The most famous of these cryptograms was the 408-symbol cipher, sent to the San Francisco Chronicle on July 31, 1969. Published in the newspaper, it sparked immediate public interest and efforts to decode its hidden message.

Ultimately, it was a schoolteacher and his wife, Donald and Bettye Harden, who cracked the code, revealing a message filled with disturbing content but no concrete clues to the killer’s identity. Another significant cipher, the 340-symbol cryptogram, arrived with a letter dated November 8, 1969, addressed to the San Francisco Chronicle and two other newspapers. This cipher remained unsolved for decades, capturing the imagination of codebreakers around the world.

The Zodiac killer claimed responsibility for 37 murders and sent taunting letters and cryptic messages to newspapers. The known victims of the Zodiac Killer include David Faraday and Betty Lou Jensen, Michael Mageau and Darlene Ferrin, Bryan Hartnell and Cecelia Shepard, and taxi driver Paul Stine. He’s also suspected in other cases, such as Donna Lass and Cheri Jo Bates, though the evidence linking him to these murders is less substantial. Find out more about this mystery killer below.