10 Reasons Why Zodiac Killer MAY Have Been Solved

The above entries cover the most compelling "evidence" linking Doerr to Zodiac, but it's also only just scratching the surface of everything Kobek uncovered in his book. Here are some of the other, more scattered coincidences and similarities worth thinking about.

- One of Doerr's 1960s music zines was heavily inspired by Gilbert and Sullivan, who are also referenced in at least three of Zodiac's letters.

- In later life, Doerr was confirmed to own a sky blue '63 Chevy Nova similar to one seen at Lake Berryessa on the day of Zodiac's attack.

- Doerr drew diagrams in many of his zines which look superficially similar to Zodiac's bus bomb drawings.

- Doerr was on the mailing list of right-wing militia The Minutemen, who used a gunsight logo similar to Zodiac's. Also, they published the bomb formula reproduced by both Doerr and Zodiac, and offered advice on how to send mail anonymously and acquire untraceable weaponry.

- Zodiac wore military-issued Wingwalker boots, which Doerr would've had easy access to because he spent decades working at Vallejo's Mare Island Naval Base.

- The year after Zodiac used one-cent stamps to post a letter, Doerr suggested using one-cent stamps to spite the post office for raising their stamp costs. Zodiac also used an out-of-circulation commemorative stamp for his one of his letters, while Doerr had spoken about collecting commemorative stamps, and both used the same eight-cent Eisenhower stamp within a year of one another.

- Zodiac was said to use a pencil flashlight as a gun sight in the dark, as was detailed in a magazine, Popular Science, that Doerr collected.

- Zodiac referenced the Sierra Club in one of his postcards, as does Doerr in numerous issues of Pioneer.

Separately, these might be cute coincidences, but together? They form a fascinating picture of Doerr as a person who should be considered at least a major person of interest in the Zodiac investigation.