Case summary
In 1968–69 at least five murders in Northern California were committed by a perpetrator who called himself 'Zodiac' and mailed ciphered letters to the press. The 340-character cipher was cracked by an independent team in 2020; the perpetrator has never been identified and the case remains open.
Timeline
- 1968-12-20First confirmed attack on Lake Herman Road: two teenagers killed.
- 1969-07-04Blue Rock Springs attack; the perpetrator phoned the police.
- 1969-08-01First cipher letters (Z408) mailed to three newspapers.
- 1969-08-08Z408 was solved within a week by the Hardens.
- 1969-10-11Cab driver Paul Stine was killed in San Francisco; a shirt piece was mailed with a letter.
- 1969-11-08The unsolved 340-character cipher (Z340) was mailed.
- 2020-12-05Z340 was cracked by Oranchak, Eycke and Blake; it contained no identifying information.
- 2021-10SFPD confirmed the case remains open and media 'solved' claims are unverified.
People and connections
- Zodiac
The name the perpetrator gave himself; never identified.
- Paul Stine
Last confirmed victim; scene in Presidio Heights, San Francisco.
- San Francisco Chronicle
Primary recipient of the letters; its archive is a primary source.
- Z340
Transposition-substitution cipher unsolved for 51 years.
- Zodiac to San Francisco ChronicleLetter traffic between 1969 and 1974
- Z340 to ZodiacThe solution confirmed authorship claims but gave no identity
Findings
Five murders and two attempted murders are tied to the same perpetrator via letter content and scene evidence.
The 2020 solution of Z340 was confirmed by the FBI.
A single perpetrator is highly probable; some attributed incidents (e.g. Riverside 1966) remain disputed.
The 2021 media claim that the killer was identified was not confirmed by law enforcement.
No suspect, including Arthur Leigh Allen, has ever produced a definitive physical-evidence match.
Documents
- DocumentFBI Vault Zodiac filesScanned official paperwork including cryptanalysis correspondence.
- DocumentZ408 and Z340 cipher textsCopies of the original cipher pages mailed to newspapers.
- MapAttack locations mapIncident points in Benicia, Vallejo, Napa and San Francisco.
Sources
Locations
- Presidio Heights (Stine scene)37.79°, -122.46°
- Lake Berryessa attack38.55°, -122.23°
Researcher's note
The Z340 solution became checkable because several researchers published their work openly. The other part of this file is less satisfying: many names have been presented as the killer, and none has crossed the evidence threshold.
Recent checks
- 2026-06-02FBI Vault links checked; the Riverside connection remains flagged as contested.
- 2026-01-14Z340 solution write-up added to sources.