Z13 Reality Check: The “Marvin Margolis (aka Marvin Merrill)” Claim Examined

By Steve Hodel | February 23, 2026 |
February 23, 2026
Birch Bay, Washington
Every few years, someone claims to have cracked the Zodiac’s 13-symbol “My name is…” cipher. The latest headline-maker says it spells MARVIN MERRILL — reportedly an alias used by Marvin Margolis.
The name itself is unfamiliar to many readers, which makes it especially important to examine whether the cipher actually supports it.
Strip away the excitement and apply basic cipher rules, and the Merrill claim runs into immediate trouble. You don’t need advanced math to see why.
What the Zodiac Actually Gave Us

The Z13 cipher contains 13 symbols. Several of those symbols repeat in specific positions. That matters.
Because of those repeats, any valid solution must follow a fixed letter pattern if we treat the cipher the same way Zodiac’s solved ciphers work — one symbol equals one letter.
In plain English, any clean solution must obey these four rules:
• Letter 1 must equal Letter 12
• Letter 3 must equal Letter 11
• Letter 8 must equal Letter 13
• Letters 5, 7, and 9 must all be the same letter
Think of it like a combination lock. If a proposed name doesn’t match this pattern, it is not a clean fit.
Put “MARVIN MERRILL” to the Test
Write it out: MARVINMERRILL

Under normal Zodiac-style substitution, the Merrill name does not satisfy the cipher’s required structure. That is the central technical failure.
Regardless of statistical scoring or computational assistance, a proposed plaintext must first obey the symbol-repeat pattern. On that basic structural test, the Merrill reading falls short.
Why Frequency Matching Isn’t Enough
With only 13 characters, many different names can be made to share similar letter counts. This is a well-known trap in short ciphers.
Matching frequency alone is like saying: “The suspect is a six-foot male wearing shoes — it fits a lot of people.”
Experienced cryptanalysts understand that at this length, positional structure matters far more than raw counts.
About the “Leading Cryptologists” Claim
Media accounts have cited former NSA cryptographer Ed Giorgio, along with crypto-mathematicians Patrick Henry and Rich Wisniewski, as viewing the Merrill proposal favorably. However, the underlying methodology and verification process have not been publicly released for independent examination.
Reasonable experts can disagree — particularly with a cipher as short as Z13, which is mathematically underdetermined and prone to overfitting. However, regardless of statistical or computer-assisted approaches, any proposed solution must still satisfy the basic structural constraints imposed by the repeating symbols.
On that standard, the Merrill reading does not hold up.
The Larger Historical Reality
In his July 31, 1969 letters accompanying the 408 cipher, Zodiac explicitly claimed: “In this cipher is my idenify.” (Zodiac’s misspelling)
When the 408 was solved, no name appeared. No identity. Just more taunting.
Zodiac reinforced that posture in his November 9, 1969 letter, writing: “I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife.” The statement is consistent with a pattern of deliberate concealment and misdirection.
Where My Investigation Stands
For the record, I have long argued — in Most Evil (2009) and Most Evil II (2015) — that the Zodiac and the Black Dahlia Avenger point to the same offender: Dr. George Hill Hodel.
That conclusion rests on a broad evidentiary foundation developed over decades, including documented LAPD interest in Hodel in 1950 and later re-examination of the case in 2003. It does not depend on any single cipher claim.
Whether Z13 ultimately yields a verifiable name — or proves to be another deliberate Zodiac tease — remains an open question.
The Bottom Line
The Merrill proposal does not withstand even basic structural scrutiny.
Until a solution emerges that uniquely and cleanly falls out of the cipher itself — rather than being fitted to it — the Z13 remains unsolved and very likely was meant to be.
— Steve Hodel
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3 Comments

  1. Luigi Warren on February 23, 2026 at 3:29 pm

    Steve:

    I don’t fully agree with this critique. It seems to me quite likely the Z13 (and the Z32) are anagrams. The letters might be transposed randomly or according to some fixed scheme — it hardly matters in a short cipher. My eyes rolled when I heard the song-and-dance about military code-cracking, AI, and transposition schemes in relation to the MARVIN MERRILL solution. Uh, it’s an anagram with the right number of letters and repeats — end of story. I agree that the constraints set by the overall letter count and repeated symbol count are not very restrictive. That is especially true given: (a) any name can be spelled out in multiple forms, e.g., MARVIN MERRILL can be plausibly rendered as some variation of M[ARV[IN]] [S[KIPTON]] M[ERRILL], allowing multiple “shots on goal” — plus this guy had other names, and spaces might or might not be encoded; (b) there is a large universe of people and therefore names and name variants you could chose to build into credible suspects if you are not too particular about how you “enhance” the evidence (remodeling jawlines, adding glasses, etc.) Also, the inference that each symbol stands for a unique plaintext letter isn’t strong in this case as it seems reasonable the 8-ball symbol could be a wildcard, hinted at by the “Magic 8-Ball” association. So, we can’t have much confidence that the assumed constraints even apply.

    If the short Zodiac ciphers have unique keys, then (most likely) they are not “fair play” in the sense that there is no realistic way to attack them as ciphers based on statistics, and hence no sport or kick in the game for the puzzle-poser. True, there might be some other clever clues hidden in the Zodiac letters to somehow make the game “sporting,” but I haven’t seen any credible theories on that score. Alternatively, if their solution comes through cracking the key to the Z340, the answers would be too easy and perhaps dangerously unambiguous unless the messages are scrambled — indeed, we would already have those solutions. My guess is the short ciphers are anagrams employing the key from the hard-but-crackable Z340. There might be additional minor wrinkles. In the Z13, the 8-ball is not in the known Z340 cypher alphabet, and perhaps it’s a true wild card. I believe there are one or two symbols in the Z32 (Celebrity Cypher) which are also outside the known Z340 alphabet. If this is right, the Z13 and Z32 have been rendered tractable but still tough — and probably forever ambiguous — now that the Z340 has finally been cracked. The best hope of solving the anagrams would be to consider who the Zodiac might plausibly be, and the unacknowledged crimes he might plausibly have committed. That part of the “MARVIN MERRILL” hoopla I can agree with.

    -LW

    Reply
    • Luigi Warren on February 23, 2026 at 3:43 pm

      Correction: The Z32 is the Mt. Diablo Code cipher, Z63 is the Celebrity Cipher. Anyway, same reasoning applies.

      Reply
      • Steve Hodel on February 23, 2026 at 3:57 pm

        LW — I always appreciate your thoughtful take. I agree the short Zodiac ciphers leave plenty of room for interpretation, and ambiguity may well have been part of the design. Cipher analysis is not really my wheelhouse. I tend to view this as I do psychology — multi-directional, open to multiple interpretations. As always, I value your continued work on the puzzle side of the equation.

        Reply

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