The Zodiac Killer: five murders, four ciphers and a case that is still open

• AttacksFour confirmed, December 1968 – October 1969
• VictimsSeven: five killed, two survived
• WhereBenicia, Vallejo, Lake Berryessa (Napa County), San Francisco
• LettersAbout two dozen, 1969–1974, most to the San Francisco Chronicle
• CiphersFour: Z408 solved 1969, Z340 solved 2020, Z13 and Z32 unsolved
• StatusUnsolved. No one has ever been arrested or charged

The Zodiac Killer is one of the most famous unsolved serial murder cases in the United States. Between December 1968 and October 1969 someone shot or stabbed seven people in Northern California, killing five, and then spent five years writing to the newspapers about it: taunting letters, a bloodied scrap of a victim's shirt, and ciphers that amateurs and the FBI have been working on ever since. One of them was finally read in December 2020. The man who wrote it has never been identified.

This page sets out what is documented: the four attacks that investigators attribute to the Zodiac, the letters and ciphers, the suspects as far as the record goes, and the state of the case now. Where sources disagree on a date or a number, the page says so. It names no one as the killer, because no one has ever been charged.

Lake Herman Road, December 1968

On the night of 20 December 1968, David Faraday, 17, and Betty Lou Jensen, 16, two high school students on a date, were parked on Lake Herman Road just inside the Benicia city limits, on the Vallejo side. Someone shot them both with a .22-caliber pistol. Jensen was shot in the back as she ran from the car. Faraday was shot in the head; he was still alive when he was found and died at the hospital. Some accounts place the scene outside Vallejo; both are right, since the spot sits inside Benicia on the edge of Vallejo.

At the time nobody connected the killings to anything. The name Zodiac did not exist yet.

Blue Rock Springs, July 1969

Around midnight on the night of 4–5 July 1969, Darlene Ferrin, 22, and Michael Mageau, 19, were shot in Ferrin's parked car at Blue Rock Springs Park in Vallejo. Sources split on the date: most give 4 July, some 5 July, because the shooting happened just after midnight. The killer himself later wrote “7-4-69”.

Ferrin died. Mageau survived and gave police a description of the attacker. The weapon was a 9mm pistol. About forty minutes later a man called the Vallejo police from a payphone, reported the shooting, and claimed the Lake Herman Road murders as well. That call is what first linked the two attacks.

The first letters and the name

On 31 July 1969 three almost identical letters were mailed to the San Francisco Chronicle, the San Francisco Examiner and the Vallejo Times-Herald; they arrived on 1 August. The writer claimed both attacks and gave details that police said only the killer could know. Each letter carried one third of a cipher, with a demand that it run on the front page and a threat of more killing if it did not.

Those letters were not yet signed “Zodiac”. The name first appeared in a letter to the Examiner received on 4 August 1969, which opened: “This is the Zodiac speaking.” The letters were signed with a circle crossed by a cross, like a gunsight. Why he chose the name has never been established.

The 408 cipher, cracked in a week

The three thirds fit together into a single cipher of 408 symbols, now called Z408. It was solved within about a week by Donald and Bettye Harden, a schoolteacher and his wife from Salinas. The exact day varies by source: 5 August 1969 in some accounts, 8 August in others, which is the day the Chronicle received their solution. (A 2007 FBI story calls the Hardens “two university professors”; every other source, including the Chronicle, calls him a schoolteacher, and that is the version used here.)

The message began “I like killing people because it is so much fun” and called man “the most dangerous animal”, an echo of the short story “The Most Dangerous Game”. It did not contain a name. The last eighteen letters have never been convincingly read.

Lake Berryessa, September 1969

On 27 September 1969 Cecelia Shepard, 22, and Bryan Hartnell, 20, were picnicking on the shore of Lake Berryessa in Napa County when a man in an executioner-style hood approached them. The hood bore the circle-and-cross symbol on the chest. He had them tied with pre-cut lengths of clothesline and then stabbed them both.

Hartnell survived. Shepard died of her wounds two days later, on 29 September. Before leaving, the attacker drew the circle-cross on the door of Hartnell's car and wrote the dates of his attacks beneath it: “Vallejo / 12-20-68 / 7-4-69 / Sept 27–69–6:30 / by knife”. He then called the Napa County Sheriff's office from a payphone to report it; the phone was found off the hook. The car door is still held as evidence.

Paul Stine, San Francisco, October 1969

On 11 October 1969, cab driver Paul Stine, 29, was shot in the head with a 9mm pistol in his taxi in the Presidio Heights neighbourhood of San Francisco. The killer took his wallet and keys and tore off a piece of his shirt. Three teenagers watched from across the street and called the police; their description produced the composite sketch of the Zodiac. Police first treated it as a robbery.

It was not. A letter postmarked 13 October reached the Chronicle the next day and ran on 15 October. Inside was a bloodied piece of Stine's shirt, and a threat to shoot out the tyres of a school bus and “pick off the kiddies”. Stine is the last killing that investigators officially attribute to the Zodiac.

The 340 cipher, read after 51 years

On 8 November 1969 the Zodiac mailed the Chronicle a greeting card with a second cipher, 340 characters long. For half a century it defeated everyone who tried it. On 5 December 2020 three amateurs sent the FBI a solution: David Oranchak, a software developer in Virginia; Sam Blake, a mathematician in Australia; and Jarl Van Eycke, a programmer in Belgium who wrote the AZdecrypt software. To find it they tested about 650,000 different ways of reading the symbols.

On 11 December 2020 the FBI confirmed it. The San Francisco field office said it was aware that a cipher attributed to the Zodiac Killer “was recently solved by private citizens” and that the case “remains an ongoing investigation”. The message does not contain a name. It says “that wasnt me on the TV show”, meaning a caller who spoke with the attorney Melvin Belli on a live KGO-TV morning programme on 22 October 1969 and was later found not to be the Zodiac, and it says he is not afraid of the gas chamber.

Z13 and Z32: the ciphers nobody has read

Two short ciphers remain unsolved. Z13 came in a letter dated 20 April 1970 that begins “My name is —” followed by thirteen symbols. Z32 was mailed on 26 June 1970 with a Bay Area road map marked at Mount Diablo, and the writer claimed it gave the location of a bomb. Both are too short to produce a single solution that can be checked, which is why there are hundreds of proposed answers and no accepted one.

That has not stopped people claiming them. In December 2025, for example, a self-taught cryptographer said he had read Z13 as an alias of a man who died in 1993; no law-enforcement agency has confirmed it.

How many letters, how many victims

There is no single agreed count of the letters. The Chronicle counts 22 known letters, 17 of them to the Chronicle itself; Wikipedia's list of confirmed correspondence has 15 mailings, because it counts the triple letter of July 1969 once and leaves out letters of doubtful authorship. “About two dozen letters between 1969 and 1974” is the safe figure. The last one generally accepted as genuine was postmarked 29 January 1974. Several later letters, in 1974 and 1978, are disputed.

The number of victims he claimed kept rising in the letters: seven in November 1969, then ten, thirteen, seventeen in March 1971, and finally “Me = 37, SFPD = 0” in that January 1974 letter. Investigators have only ever confirmed five dead and two survivors.

Other cases have been linked to him by writers and amateur investigators, and none has been officially attributed. On 22 March 1970 Kathleen Johns, 22, was driving on Highway 132 with her baby daughter when a man flagged her down, claimed her wheel was loose, and then drove her around for hours before she escaped; at the police station she recognised the composite on the wanted poster. A later Zodiac letter appeared to claim it, but police never attributed it. The 1966 Riverside murder of Cheri Jo Bates is often mentioned too; Riverside police have said the Zodiac did not kill her.

The suspects

The only person investigators have ever publicly named as a suspect is Arthur Leigh Allen of Vallejo, a former elementary school teacher with a conviction for child molestation. Police searched his home in 1972, in 1991 and again two days after his death. Michael Mageau, the Blue Rock Springs survivor, picked him from a photo lineup more than twenty years after the attack (in 1991 by one account; another puts it a month before Allen's death), though he had never had a good look at the gunman. Allen was never charged. He died of a heart attack on 26 August 1992, aged 58.

The physical evidence did not tie him to the letters. His fingerprints and handwriting did not match. In 2002 the San Francisco police crime lab developed a partial DNA profile from a stamp on a Zodiac envelope, and it did not match Allen either, but the sample was so thin that the Chronicle describes the result as inconclusive, and it has since been questioned whether that DNA came from the killer at all. Sources disagree on where that leaves him: some say he was ultimately cleared, others that he was never ruled out. Robert Graysmith's 2002 book Zodiac Unmasked argues that he was the Zodiac. That is an author's case, not a police finding.

In October 2021 a private group of about forty volunteers calling itself the Case Breakers announced that it had identified the Zodiac as a man who had died in 2018. The FBI's response was short: “The Zodiac killer case remains open. We have no new information to share at the moment.” Riverside police rejected the group's link to the Bates murder outright. The man they named was never charged and never named a suspect by any police agency.

Where the case stands

The investigation is shared by the places where the killings happened, San Francisco, Solano County (Benicia and Vallejo) and Napa County, with support from the FBI. The San Francisco police marked their Zodiac case inactive in April 2004, citing caseload, and later reactivated it; sources give different years for the reactivation. In 2010 Napa County sent the Lake Berryessa evidence, including the clotheslines, to the California DOJ DNA lab, which could not get usable DNA. In 2018, after the Golden State Killer was identified through genetic genealogy, the Vallejo police sent Zodiac envelopes and stamps for new testing. No result has been announced.

The FBI's most recent statements, in 2020 and 2021, both say the same thing: the case is open.

Zodiac, Dirty Harry and the books

Robert Graysmith was a political cartoonist at the Chronicle when the letters arrived. His book Zodiac (1986) became the standard popular account, followed by Zodiac Unmasked (2002). David Fincher's film Zodiac, based on both books, opened on 2 March 2007, with Jake Gyllenhaal as Graysmith, Mark Ruffalo as SFPD inspector Dave Toschi and Robert Downey Jr. as Chronicle reporter Paul Avery, who received a Zodiac Halloween card in October 1970. Long before that, the killer called Scorpio in Dirty Harry (1971) was modelled loosely on the Zodiac; the film's school bus hijacking echoes the threat in the Stine letter.

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Questions people ask

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Sources

Every date and name on this page was checked against at least two of the following. Where they disagree, the disagreement is stated in the text rather than resolved silently.

1. Zodiac Killer timelineSan Francisco Chronicle
2. Report on the 340 cipher solution (Kevin Fagan)San Francisco Chronicle, 11 December 2020
3. The Zodiac case 50 years laterSan Francisco Chronicle, December 2018
4. How the Chronicle covered the Zodiac lettersSan Francisco Chronicle
5. Police take another look at Zodiac DNASan Francisco Chronicle, May 2018
6. Report on the Case Breakers claimSan Francisco Chronicle, October 2021
7. Zodiac KillerWikipedia
8. Arthur Leigh AllenWikipedia
9. Zodiac KillerBiography.com
10. The Zodiac KillerCrime+Investigation UK
11. FBI story on the Zodiac caseFBI, March 2007 (archived copy)
12. The solution of the Zodiac Killer's 340-character cipherOranchak, Blake, Van Eycke, arXiv 2403.17350
13. Report on the 340 cipher solutionThe Register, 12 December 2020
14. Primetime report on the Zodiac DNA testABC News, 2002
15. Decades later, Zodiac murders still draw sleuthsNPR, 2 March 2007
16. Hope for new DNA leads in Zodiac Killer caseNPR, 4 May 2018
17. The Case Breakers claim and other Zodiac suspectsKQED, 2021
18. Report on the Case Breakers claimABC News (Australia), 7 October 2021

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