The Zodiac Killer: Five Killings, Four Ciphers, and Fifty-Seven Years of Open File

Five killings, three sites, ten months.

The Zodiac Killer's confirmed murders occurred between December 20, 1968 and October 11, 1969 in three Northern California counties. The first attack killed David Faraday and Betty Lou Jensen on a rural road outside Benicia (Solano County). The second killed Darlene Ferrin and wounded Michael Mageau at a parking spot at Blue Rock Springs Park near Vallejo. The third killed Cecelia Shepard and wounded Bryan Hartnell at Lake Berryessa in Napa County, the only attack at which the killer was reportedly seen wearing a hooded costume marked with a crosshair symbol. The fourth killed San Francisco cab driver Paul Stine in the Presidio Heights neighborhood. Five killings, two survivors, and a pattern of letters to the San Francisco Chronicle, the Vallejo Times-Herald, and the San Francisco Examiner in which the writer claimed responsibility, threatened additional victims, taunted police, and enclosed four cipher messages of varying length. The first cipher (Z408, 408 characters in three parts) was solved within a month of its publication by an amateur Salinas teacher and his wife. The second (Z340, 340 characters) remained unsolved for 51 years and was decoded in December 2020 by a small team of researchers using a combination of pattern analysis and software. The remaining two short ciphers (Z32 and Z13) remain unsolved. The killer's identity, despite a list of more than 2,500 suspects investigated by various law enforcement agencies over five decades, remains undetermined. The case is administratively open across multiple jurisdictions.

The documented record.

The killings

December 20, 1968 — Lake Herman Road, Benicia. Betty Lou Jensen, 16, and David Faraday, 17, were on what appears to have been their first date. They were parked off Lake Herman Road in rural Solano County. A passing motorist found them after a shooting that occurred at approximately 11:00 pm; both were dead at the scene from .22-caliber gunshots. The killer fired at the car from outside, then shot Faraday in the head and Jensen as she fled. The Solano County Sheriff investigated; the killer left no notes or claim at the scene. Verified [1]

July 4, 1969 — Blue Rock Springs Park, Vallejo. Darlene Ferrin, 22, and Michael Mageau, 19, were parked in Mageau's car. At approximately midnight, a man approached the car with a flashlight and a 9mm pistol and fired multiple times through the open window. Ferrin died at the hospital; Mageau survived, severely wounded. He later described the shooter as a heavy-set white man wearing a navy windbreaker. Approximately 40 minutes later, a man called the Vallejo Police Department from a pay phone and claimed responsibility for both the July 4 and December 20 shootings, providing operational details only the killer could have known. The call was traced to a phone booth near Joseph Allen's gas station, two blocks from the Vallejo police station. Verified [2]

July 31, 1969 — Letters with first cipher. Three letters arrived at the San Francisco Chronicle, the San Francisco Examiner, and the Vallejo Times-Herald. Each contained one-third of a 408-character cipher and demanded publication. The letters identified details of the December and July killings that had not been released to the public, establishing authenticity. The newspapers, in consultation with the Vallejo Police, published the cipher. Donald and Bettye Harden, a married couple in Salinas, solved Z408 within approximately one week. The decoded text was not a name or location but a manifesto: "I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN..." [3] Verified

August 4, 1969 — First "Zodiac" letter. A subsequent letter to the San Francisco Examiner opened with "This is the Zodiac speaking" — the first use of the name the killer chose for himself, accompanied by a crosshair/circle symbol that would appear in subsequent correspondence.

September 27, 1969 — Lake Berryessa, Napa County. Bryan Hartnell, 20, and Cecelia Shepard, 22, were at a remote shore picnic area on Lake Berryessa. A man wearing a hooded executioner-style costume with a white crosshair symbol on the chest approached, told them he was an escaped convict, tied them up, and stabbed both repeatedly. Shepard died. Hartnell survived, severely wounded. The attacker wrote on the door of Hartnell's car the dates of the previous Zodiac murders and the crosshair symbol. The attacker subsequently called Napa Police from a pay phone in Napa to report the crime. Verified [4]

October 11, 1969 — Presidio Heights, San Francisco. Paul Stine, 29, a Yellow Cab driver, picked up a fare in San Francisco who directed him to the Presidio Heights area. At Washington and Cherry Streets, the passenger shot Stine in the head and removed pieces of his shirt before fleeing. Three teenagers in a nearby home saw the killer leave the cab; their description (a stocky white male in his late 30s wearing glasses) became the most reliable single-source description in the case. Patrol officers responding to the scene apparently encountered the fleeing killer briefly without recognizing him, due to a mistakenly-broadcast description identifying a Black male suspect. Verified [5]

Three days later, the Chronicle received a letter from the Zodiac claiming responsibility for Stine, enclosing a scrap of Stine's bloody shirt as proof.

The cipher work

Z408 (solved August 1969). A 408-character cipher in three approximately-equal parts, distributed across three newspapers. Solved within approximately one week by Donald Gene Harden, a Salinas high school teacher, and his wife Bettye June Harden. The Hardens used what amounts to a basic frequency analysis combined with an inspired guess: they assumed the cipher would begin with "I" and that the killer's ego would lead him to use the word "kill" repeatedly. The decoded text is a manifesto and contains no name, location, or identifying information beyond the killer's stated worldview. Verified [3]

Z340 (solved December 2020). A 340-character cipher mailed to the San Francisco Chronicle on November 8, 1969. It remained unsolved for 51 years. In December 2020, a team consisting of David Oranchak (an American software developer), Sam Blake (an Australian mathematician), and Jarl Van Eycke (a Belgian software developer) cracked the cipher using a combination of new analytical tools and the insight that the cipher was transposed in a non-obvious pattern. The decoded text continues the killer's taunting tone — "I HOPE YOU ARE HAVING LOTS OF FUN IN TRYING TO CATCH ME" — but again contains no identifying information. The solve was authenticated by the FBI's Cryptanalysis and Racketeering Records Unit. Verified [6]

Z32 (unsolved). A 32-character cipher in a June 26, 1970 letter, supposedly identifying the location of a hidden bomb. Various decryption claims have been made; none have been authenticated.

Z13 (unsolved). A 13-character cipher in an April 20, 1970 letter, supposedly identifying the killer's name. The short length makes it nearly impossible to verify any proposed solution — a 13-character string has too few constraints to distinguish a correct solution from a coincidental fit. Various candidate solutions have been proposed; none have been confirmed.

The investigative history

Multiple law enforcement agencies have investigated the case across jurisdictions: the Solano County Sheriff's Office (Lake Herman Road), the Vallejo Police Department (Blue Rock Springs), the Napa County Sheriff's Office (Lake Berryessa), the San Francisco Police Department (Stine, lead jurisdiction on the broader case), and the FBI (cipher and interstate aspects). At various periods these agencies have collaborated formally and informally. The SFPD's Zodiac case file was reopened, closed, and reopened multiple times over the decades and remains administratively open as of 2026 [7].

The DNA work

Partial DNA was developed in the 2000s from saliva on Zodiac envelope flaps and stamps. The profile is partial and has been used to exclude (not include) candidate suspects. The most-named suspect, Arthur Leigh Allen, was excluded by this DNA work in 2002 according to SFPD; the exclusion has been the subject of subsequent dispute about the DNA sample's chain of custody and analytical methodology. Disputed [8]

Modern genetic genealogy techniques — the same family-tree-based approach that identified the Golden State Killer in 2018 — have not yet produced an authenticated Zodiac identification, although periodic announcements have claimed candidates. The constraint is that the available Zodiac DNA is a partial profile from contamination-vulnerable materials (envelope adhesive 50+ years old), and the genealogy databases used in the Golden State Killer case require a more complete profile than has been developed from the Zodiac samples.

The most-named suspects.

Arthur Leigh Allen (deceased 1992)

The single most-investigated suspect across the case's history. Argument: behavioral similarity to witness descriptions; circumstantial location overlap with the killings; a 1971 search of his trailer turned up materials (including a Zodiac-similar watch face) of investigative interest; statements by his brother and brother's wife implicating him. Claimed by the Vallejo PD primary investigators (David Toschi and others); included as the primary suspect in Robert Graysmith's Zodiac (1986).

Limits: The 2002 SFPD DNA exclusion. Allen's fingerprints did not match prints recovered from Zodiac material at scenes. The behavioral evidence is real; the physical evidence does not place him at the killings. Claimed but the case against him is weaker than the original Graysmith treatment suggested, given the DNA work.

Gary Francis Poste (deceased 2018)

Identified in 2021 by the "Case Breakers" group (a private cold-case team led by Thomas Colbert) as the killer based on photographic-comparison work, alleged scars matching witness descriptions, and claimed cipher-decoding. The Case Breakers' announcement received substantial media coverage. The FBI and SFPD both publicly declined to endorse the identification. The cipher decoding offered by the group has not been authenticated. Disputed at best; the official agencies have treated it as not meeting evidentiary standards [9].

Other notable suspects

Earl Van Best Jr., Ross Sullivan, Lawrence Kane, Rick Marshall, Ted Kaczynski (briefly considered), and dozens of others have been advanced as candidates with varying degrees of supporting argument. The aggregate pattern: each candidate accumulates a circumstantial case that fails to produce physical evidence. None has been authenticated by either DNA, fingerprint, or operational evidence linking the candidate to the actual killings.

The unanswered questions.

The killer's identity

The core unresolved question. The available DNA is partial; the witness descriptions are consistent but not specific enough to constrain a single individual; the operational pattern (stalking, motorist-with-flashlight approach, taunting communications) is distinctive but doesn't map to a known offender's signature in pre- or post-Zodiac databases.

The full count

The Zodiac himself claimed (in a 1974 letter) credit for "37 victims." Five killings are confirmed. The expanded list at most adds Cheri Jo Bates (1966, Riverside — the most credible additional candidate based on letter evidence), possibly Kathleen Johns (1970, Modesto kidnapping survivor whose account broadly fits), and others. The actual count is somewhere between five and a substantially higher number that cannot be reliably established. Disputed

The 1974 cessation

The Zodiac's last authenticated communication was the "Exorcist letter" of January 29, 1974. After that, the letters stopped. Whether the killer died, was imprisoned for an unrelated offense, was institutionalized, or simply stopped communicating is undetermined. The cessation itself is a piece of evidence that would, in principle, constrain the suspect pool — but no constraint based on it has produced an authenticated identification.

The shorter ciphers

Z32 and Z13 remain unsolved. The Z13 cipher in particular — supposedly the killer's name — is short enough that the problem may be fundamentally unsolvable from the available material; too few constraints, too many candidate solutions.

Primary material.

• SFPD case file 696314 (Stine homicide), San Francisco Police Department.
• Vallejo Police Department files on the Lake Herman Road and Blue Rock Springs cases.
• Napa County Sheriff's Office files on the Lake Berryessa case.
• The original Zodiac correspondence: letters, cards, and cipher pages mailed to the SF Chronicle, the SF Examiner, and the Vallejo Times-Herald, 1969–1974. Some originals in police custody; reproductions widely available.
• The Z408 and Z340 cipher solutions, FBI-authenticated.
• Witness descriptions and sketches from surviving victims and the Presidio Heights witnesses.
• Partial DNA profiles developed from envelope adhesive, in evidence custody.

The sequence.

1. December 20, 1968 Faraday and Jensen killed on Lake Herman Road.
2. July 4, 1969 Ferrin killed at Blue Rock Springs; Mageau survives. Killer calls Vallejo PD claiming credit.
3. July 31, 1969 First letters arrive at three Bay Area newspapers with cipher pieces.
4. ~August 7, 1969 Donald and Bettye Harden decode Z408.
5. August 4, 1969 First letter signed "Zodiac" arrives at the Examiner.
6. September 27, 1969 Hartnell and Shepard attacked at Lake Berryessa. Shepard dies; Hartnell survives.
7. October 11, 1969 Paul Stine killed in Presidio Heights, San Francisco.
8. October 14, 1969 Letter to the Chronicle claims Stine; includes shirt fabric.
9. November 8, 1969 Z340 cipher mailed to the Chronicle.
10. January 29, 1974 Last authenticated Zodiac letter (the "Exorcist letter").
11. 1986 Robert Graysmith publishes Zodiac, naming Allen as primary suspect.
12. 1992 Arthur Leigh Allen dies.
13. 2002 SFPD publicly excludes Allen via partial DNA.
14. 2007 David Fincher's Zodiac film released, refocusing public attention.
15. December 5, 2020 Oranchak/Blake/Van Eycke team announce Z340 solution; FBI authenticates.
16. October 2021 Case Breakers announce Gary Francis Poste identification; FBI and SFPD decline to endorse.
17. 2026 Case administratively open across multiple jurisdictions.

Cases on this archive that connect.

Planned: the Golden State Killer (the methodology of forensic genealogy that ultimately identified Joseph DeAngelo in 2018, and what it would take to apply that methodology to the Zodiac DNA); the Cheri Jo Bates case (Riverside 1966, the most credible additional candidate Zodiac victim); the Boy in the Box (2022 identification via similar genealogical techniques). The category-defining structural property: cases where partial physical evidence combined with mid-2020s techniques may eventually move them from this pillar to "solved."

Full bibliography.

1. Solano County Sheriff's Office. Case files, Lake Herman Road killings (December 20, 1968).
2. Vallejo Police Department. Case files, Blue Rock Springs (July 4, 1969). Includes the 12:40 am phone-claim transcript.
3. The Z408 cipher and its 1969 solution by Donald and Bettye Harden. Original cipher in three parts mailed July 31, 1969; solution authenticated by the FBI.
4. Napa County Sheriff's Office. Case files, Lake Berryessa (September 27, 1969).
5. San Francisco Police Department. Case 696314, Stine homicide (October 11, 1969).
6. Oranchak, David. Z340 cipher solution announcement, December 5, 2020, with FBI authentication. Subsequent peer-reviewed publication.
7. Graysmith, Robert. Zodiac. St. Martin's Press, 1986. The most widely-read public treatment; specific claims now substantially revised by DNA work.
8. SFPD public statement on Allen DNA exclusion, 2002.
9. FBI public statement on Case Breakers / Poste announcement, 2021.
10. Voigt, Tom. zodiackiller.com archive (online primary-document collection; long-running independent research site).
11. Penn, Gareth. Times 17: The Amazing Story of the Zodiac Murders in California and Massachusetts. Foxglove Press, 1987. Notable for the "Theodore Kaczynski Zodiac" hypothesis later considered and rejected.