The Zodiac Killer's identity is known and has been hidden or solved by amateurs

The case he built to be solved

Here is what makes the Zodiac different from an ordinary cold case, and why the belief that it can still be cracked is not foolish. The killer deliberately turned his own crimes into a puzzle and handed it to the public. He did not hide. He wrote, he named himself, he drew a symbol, and above all he sent ciphers, coded messages that promised to reward anyone clever enough to read them.

And they could be read. The first and longest, the 408 cipher mailed in three pieces on 31 July 1969, was broken within about a week, not by the FBI or Navy cryptanalysts who also tried, but by a married pair of high-school teachers from Salinas, Donald and Bettye Harden. Bettye guessed the vain killer would begin with “I” and would use the word “kill,” and that crib cracked it open. The decoded text began, “I like killing people because it is so much fun.” For more than 50 years the second long cipher, the 340, resisted everyone, until December 2020, when an American software developer, an Australian mathematician, and a Belgian codebreaker, David Oranchak, Sam Blake, and Jarl Van Eycke, finally solved it and the FBI confirmed the answer.

He built the case to be solved, and twice, amateurs solved the part he dared them to. It is not madness to think the rest might yield too.

When two of a killer's puzzles fall to persistent amateurs, it becomes very easy to believe the last puzzle, his name, is just one insight away. That is the engine of every Zodiac theory: the sense that the answer is encoded somewhere in the material he left behind, waiting for the right reader.

What the solved ciphers did not contain

Here is the deflating fact at the center of the case. Both cracked ciphers have been read in full, and neither one names him. The 408 is a boast about the thrill of killing and a bizarre claim that his victims will become his slaves in an afterlife. The 340, when it finally opened in 2020, turned out to be more taunting in the same vein: I hope you are having lots of fun in trying to catch me, it says, and it insists he is not afraid of the gas chamber. Both are chilling. Neither is a confession with a signature. The single most anticipated revelation in the case, the moment a solved code would spell out a real name, simply never arrived.

That leaves the two shortciphers, and this is where the amateur “solutions” live. In one 13-symbol message the Zodiac wrote that it contained his name; there is also a 32-symbol cipher. The problem is mathematical, not conspiratorial. Thirteen or thirty-two symbols are far too few to pin down one and only one answer. With a message that short, a determined solver can force it to spell almost any name they already suspect, which is exactly what has happened repeatedly. Cryptographers do not accept these readings, because a “solution” that only works if you assume the answer in advance proves nothing.

The physical evidence has been equally stubborn. A partial DNA profile was recovered from the stamps and envelopes of Zodiac letters, but the mailings passed through many hands over decades, so the sample may not even be the killer's, and it is too incomplete to convict anyone. Handwriting comparison, for all the letters he wrote, is interpretive and has not matched the leading suspect. Every avenue that looked like it should close the case has instead come up short of proof.

And the suspects illustrate the trap. The only person police ever publicly named was Arthur Leigh Allen, a Vallejo man investigated from 1971 onward, whose home was searched and who fit pieces of the picture. He was never charged. He died in 1992. Handwriting examiners did not match him, and the DNA reportedly did not either. Since then, self-published books and private “case-breaker” groups have each declared the mystery solved, naming different people, several of them dead and unable to answer. Those claims rest on resemblance and on contested cipher readings, not on evidence a prosecutor could use. When a dozen confident solutions all point at different men, that is the signature of an unsolved case, not a hidden answer.

Why the mystery refuses to die

Few cold cases hold the public the way this one does, and the reasons are worth naming, because they are the same forces that keep generating new “solutions.” The Zodiac made himself into a character. He had a name, a symbol, a voice on the page, and a set of puzzles, all the furniture of a story rather than a case file. Stories demand endings, and this one refuses to provide one, so people keep trying to write it themselves.

The near-misses feed the obsession. Amateurs really did crack two of his codes, so the fantasy of being the person who cracks the last one, who reads his name out of the symbols, is not entirely irrational. It has just proven false every time so far. Add a hit film, a shelf of documentaries, and online communities that turn cipher-solving into a competitive sport, and there is a permanent engine producing candidate killers.

There is also the intolerable shape of the thing. A man taunted the police, killed at least five people, promised more, and was never caught. Naming him, anyone, restores a sense of justice and control that the honest answer withholds. That is why each new book arrives with total certainty and a different suspect. The certainty is doing emotional work the evidence cannot do. It is precisely because the case is unbearable to leave open that so many people keep insisting, against the proof, that it is already closed.