An engineer and amateur codebreaker believes that he has cracked the final two scrambled messages of the Zodiac Killer, one of which appears to reveal his identity.
In the late 1960s, heading into the early 1970s, a serial killer going by the pseudonym "Zodiac" murdered at least five people in California. During his spree, the killer sent taunting messages to the press written through a cipher, where letters are substituted for different letters or numbers (or in the case of the Zodiac killer, a series of symbols).
The first letters were sent to three papers in the Bay Area, each containing a different part of the cipher. The papers printed the ciphers (or cryptograms) as Zodiac threatened to kill again if his instructions weren't followed.
The cipher, which was simpler than later efforts, was solved a week later by hand on August 8, 1969, by Donald Gene and Bettye June Harden. It read:
"I LIKE KILLING PEOPLE BECAUSE IT IS SO MUCH FUN IT IS MORE FUN THAN KILLING WILD GAME IN THE FORREST BECAUSE MAN IS THE MOST DANGEROUS ANIMAL OF ALL TO KILL SOMETHING GIVES ME THE MOST THRILLING EXPERENCE IT IS EVEN BETTER THAN GETTING YOUR ROCKS OFF WITH A GIRL THE BEST PART OF IT IS THAT WHEN I DIE I WILL BE REBORN IN PARADICE AND ALL THE I HAVE KILLED WILL BECOME MY SLAVES I WILL NOT GIVE YOU MY NAME BECAUSE YOU WILL TRY TO SLOW DOWN OR STOP MY COLLECTING OF SLAVES FOR MY AFTERLIFE EBEORIETEMETHHPITI".
Based on this, it's pretty incredible that he was able to come up with a cypher complicated enough to fool the FBI for years but couldn't put the effort in to give his spelling a quick double-check, or maybe ask a friend to: "look, try not to read too much into the content but can you have a quick check that my grammar's ok".
Nevertheless, further messages took until late 2020 to decipher, after being worked on for years by codebreakers.
Now, Fayçal Ziraoui claims he has cracked the final two messages in just two weeks, with use of the encryption key discovered in December. (For the rest of the article to make sense, you might want to take a look at that key for yourself).
The main problem with the final messages is the length. The Z13 message is only 13 characters long, making it a lot more difficult to figure out what the cipher could be. This is particularly frustrating, given that, according to the message preceding it, it reveals the Zodiac Killer's name.
Let's start with the Z32 cipher, as did Ziraoui. This particular 32 character cipher claimed to reveal the location of a bomb the killer had set, and came with a map showing the cities of Berkley and Oakland in California, USA.
This new solution proposes that the cipher does not have its own key, and uses a key revealed in previous messages. Ziraoui proposes that the key he used was the Z340 key, deciphered last December.
He argues that this key was not solved at the time, meaning that the killer had no need to create a new code. When used against the Z32, he claims it also draws out some sequences that almost look like words, including strings that look like scrambled versions of north ("nort" in the cipher), east, and west, which would make sense given that the cipher supposedly reveals a location. As well as this, he believes you can also see the string "I D O B L A", which is close to "diablo", fitting with Mount Diablo of California. Diablo was highlighted on the Zodiac Killer's map.
He also believes that the code revealed coordinates relating to magnetic north (the killer had written Mag. N on the map), which gives a rough idea of what sort of figures you are looking for. As well as this, he took a guess at the sort of precision that someone in the 1970s would be able to pin the location down to. With 3 digits after the decimal point, you can mark a location to within around 100 meters accuracy (328 feet). With four, you can decrease this to around 10 meters (32.8 feet), which is about the accuracy of modern-day GPS.
Using this, he guessed that the code would eventually reveal two numbers, denoting longitude and latitude, each with two numbers, followed by 3-4 numbers depending on how accurate the Zodiac killer tried to be. He also guessed that the first two numbers of the latitude needed to be around 44 – to put it near Mount Diablo – and longitude of around 60 for the same reason.
Using the Z340 cipher, and then applying a simple letter to number switch (A=2, B=2, C=3, etc) he found coordinates which he believes to be in Lake Tahoe, which he deems as interesting given that murder victim Donna Lass went missing from there a few months later, and speculates that he was sending a message that he would commit a murder at that location.
Using the remaining letters (see video above for full explanation) he found the scrambled words "find", "labor", and "day". This is significant, he believes, because labor day was when Donna Lass went missing.
If (and it is an if) this is a correct translation of the zodiac killer's message, it could mean that he used the same key again for his short Z13 cipher. This would be a lot more helpful in finding out who he is, given that the message above it says it would reveal his name.
Again, Ziraoui applied the Z340 cipher to the short string of characters. For the symbols which look like signs of the zodiac, he translated them into numerals so based on where they appear in the calendar. The remaining letters were translated to numerals using the same A=1 translation above, leaving a string of 13 numbers:
Given that the numbers were mainly repeats of 1, 4, and 5, it struck him that it was quite similar to the Trifid alphabet, another classic cipher invented in 1902. For this, however, the total number of numerals would need to be divisible by three (unless it had an extra unnecessary character).
Ziraoui's next step was to find the difference between each number (the difference between 4 and 8 is 4, the difference between 8 and 5 is 3, etc) until he was left with a 12 digit code, which he could translate into four letters using the Trifid alphabet:
434 333 113 411
K A Y R
The reason this is significant is that one of the main suspects in the case was Lawrence "Kane" Kaye, who served in the navy in World War 2 before moving to California, where he began to pick up a number of criminal convictions.
Kane was in the area at the time that the zodiac killer was active, and 45 years old at the time that the murderer was most active. Following brain damage in 1965, he was alleged to have lost the ability to control gratification. What's more, he was identified as someone who bothered victim Darlene Ferrin at a restaurant, by Darlene's sister. Kathleen Johns fled from someone who could have been the zodiac killer, and also identified Kane as her potential abductor, while a retired police officer also claimed that Kane's name had been embedded in the killer's code.
While it's easy to say "case closed", the reaction to Ziraou's solution has been mixed. Cryptography specialist at France’s National Institute for Research in Digital Science and Technology Emmanuel Thomé told the New York Times that his methods were sound and that the police should investigate it seriously, while others believe he had made some arbitrary choices, and that the code is too short to be deciphered.
Ziraoui has sent his solution on to the FBI for further investigation. The FBI recently confirmed the Z340 cipher had been cracked, so it might not be too long before we know for sure.