An imprisoned murder suspect has tried to send an encrypted message to a friend. Can my readers help to break this ciphertext?

Deutsche Version des Artikels (Beta)

Two days ago, I blogged about a crime-related ciphertext from the 1930s that is unsolved to date. This message is short and probably difficult to decipher. Dave Oranchak

Source: Oranchak

…, known to my readers as a Zodiac Killer expert, has now made me aware of another crime-related cryptogram. It is much more recent and looks easier to break. Anyway, the solution is not known to me.


The killing of Ahmaud Arbery

The crime in question is the killing of 25-year-old Ahmaud Arbery.

Source: Wikimedia Commons

Wikipedia writes about this homicide case:

On February 23, 2020, Ahmaud Marquez Arbery […] was pursued and fatally shot while jogging near Brunswick in Glynn County, Georgia. Arbery had been pursued by three white residents—Travis McMichael and his father Gregory, who were armed and driving a pickup truck, and William “Roddie” Bryan, who followed Arbery in a second vehicle—and was confronted and fatally shot by Travis McMichael. Arbery’s killing and the delayed investigation and arrests of suspects reignited debates about racial inequality in the United States.

A video of the incident was recorded by a neighbor of the McMichaels, using his cellphone from his vehicle as he followed Arbery jogging down the neighborhood road.

There have been plenty of press reports on this case. Check here for a video on YouTube.


The message

According to a newspaper article Dave Oranchak informed me about, said murder supect Gregory McMichael, a 64-year-old retired district attorney investigator, tried to send the following encrypted postcard from prison to a friend:

Source: Glynn County jail

Of course, this message was against the prison’s mail policy, and so the prison staff didn’t deliver it. According to McMichael’s lawyer, this note is made up entirely of gibberish. I don’t believe this statement, but at least it is evidence that the message wasn’t deciphered immediately.

To my regret, the article doesn’t say more about this ciphertext. I’m sure that forensic codebreaking specialists looked at it, but I have no information on whether they could break it. From my view, this cryptogram is still unsolved.


Solution approaches

Let’s check the hypothesis that McMichael employed a simple substitution cipher (MASC). If this is the case, word guessing is an appropriate solving method. Obvious candidates are the ciphertext words M and MQI. Do they stand for A and AND? I can neither confirm nor reject this conjecture.

Next, the word MACRCACT catches my eye. It has the letter pattern 12343235, which is unusual enough to perform a pattern search with CrypTool 2. However, CrypTool 2 doesn’t find a word that fits. The closest I can think of is a word like ACIDICI?, which may either have to do with acid or the rock band AC/DC.

I also tried the LITIT. CrypTool 2 rendered three results:

Source: CrypTool

We can immediately rule out QUEUE, as the ciphertext letter L can’t represent the Q. It’s too frequent and appears at the end of words. HALAL would lead to the plaintext word ??A in the second line, which doesn’t make sense. SLYLY doesn’t look right, either.

As it seems, things are not that simple. Can a reader break this message anyway?

Further reading: Tony Gaffney has broken the encrypted diary of a pedophile priest


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Kommentare (9)

  1. #1 David Oranchak
    21. November 2020

    I’m starting to wonder if it’s not a simple substitution cipher, since codebreaking tools are so far unable to solve it.

    FYI here’s a reddit thread about it:

  2. #2 Richard SantaColoma
    21. November 2020

    I would worry that the cipher text is not accurate to begin with, because of the words at the top of the page, “This is a trace of an illeg[ib]le scanned document sent”.

    If this is only a “trace” of the original message, and if that message was “illegible” before being traced, we have two levels of possible error before the version we see.

    Perhaps it was traced from an impression on a pad? Anyway, I’d want to see the original that this page was created from. Is that accessible?

  3. #3 Klaus Schmeh
    22. November 2020

    >Anyway, I’d want to see the original that this page
    >was created from. Is that accessible?
    I’m afraid it’s not.

  4. #4 Jew-Lee
    22. November 2020

    Just glancing over this first impressions are that the last number might be that of a safe combo (right 18 / left 86 / right 3). My other impression is that since it looks like it might be signed and dated at the bottom the “MERGUI TAVOY” tacked on might be a battle cry or mantra …I doubt he’d sign off with “sincerely” or “love”. I suspect if it is a combination the we might get phrases such as “safe”, “combo”, or “combination” somewhere in the body of the letter.

  5. #5 Thomas
    22. November 2020

    Mergui (Myeik) and Tavoy (Dawei) are cities in Myanmar.

  6. #6 Klaus Schmeh
    22. November 2020

    >Mergui (Myeik) and Tavoy (Dawei) are
    >cities in Myanmar.
    Great find! This probably means that the signature is not encrypted.

  7. #7 Juha
    22. November 2020

    mer qui ta voy
    Does this mean something in French too?

  8. #8 Klaus Schmeh
    22. November 2020

    @Juha: I’m afraid it doesn’t.

  9. #9 Klaus Schmeh
    23. November 2020

    Joe McNicholas via Facebook:
    Probably starts out Dear.