By the fall of 1969, the Zodiac’s reign of terror over California was at its peak.
The mystery serial killer would claim the lives of at least five victims and was in the midst of his protracted cat-and-mouse game with police and the media.
He had at that stage attacked two young couples in seemingly motiveless shootings, ambushing them in their cars and leaving investigators scrambling to discern a pattern.
His methods soon shifted: in a later attack, he used a long knife to stab two college students at Lake Berryessa before shooting a San Francisco taxi driver months afterwards.
Several cryptic letters and complex ciphers were sent to local newspapers on July 31, taunting the detectives trying to catch him and plunging the public into mass panic.
Dr DCB Marsh, the president of the American Cryptogram Association and one of the top cipher experts of the time, verified the solution to the code, known as Z408, after a husband and wife from Monterey County successfully tried their hand at cracking it at their kitchen table about a week after it arrived.
The decrypted message was a disturbing monologue describing killing as ‘the most thrilling experience’, more exciting than hunting wild game, and boasting that his victims would become his slaves in paradise.
Marsh decided to play the Zodiac at his own game.
The Z13 cipher is widely believed to conceal the Zodiac’s real name, with its 13-character code preceded by the teaser: ‘My name is -‘
A composite sketch and description circulated by San Francisco Police as they tried – in vain – to catch the Zodiac killer, who terrorized northern California between 1968 and 1969
In an interview published in the San Francisco Examiner on October 22, he issued a bold challenge to the killer: to send a cipher that would reveal his true identity.
The article, titled Cipher Expert Dares Zodiac To ‘Tell’ Name, was an attempt to provoke the perpetrator, belittling his intelligence and cryptography capabilities, and goading him that he ‘wouldn’t dare’ share such a cipher because it ‘would lead to his capture.’
Seventeen days later, the Zodiac sent another cipher, the Z340, but the accompanying letter did not refer to Marsh or the gauntlet he had thrown down.
The challenge, however, was accepted beyond doubt five months later on April 20, 1970, in a handwritten letter mailed to the San Francisco Chronicle.
It simply read:
‘This is the Zodiac speaking
‘By the way have you cracked the last cipher I sent you?
‘My name is —’ followed by a 13-character cipher, now known as Z13.
Deciphering Z13, it is widely believed, would finally unmask the serial killer and solve one of the most notorious criminal cases in the world.
Yet, despite Marsh’s public provocation, the Zodiac seemed to come out on top. Neither Marsh nor any other experts succeeded in decrypting the code.
In all, four ciphers were mailed between 1969 and 1970: Z408, Z340, Z13 and then Z32. Each used different cryptography methods and appeared to grow more fiendish as the game went on.
Dr DCB Marsh, the president of the American Cryptogram Association and one of the top cipher experts of the time, challenged the Zodiac to reveal his true name in an interview he gave to the San Francisco Examiner
Z408 was cracked by schoolteacher Donald Harden and his wife, Bettye. The 340-character cipher sent on November 8 resisted codebreakers around the world until an international team finally solved it in 2020, revealing that the Zodiac had layered homophonic substitution with a transposition technique.
As it turned out, the Z340 cipher did not reveal the Zodiac’s name but was instead a rambling message in which he mocked investigators, denied appearing on a recent TV show and boasted that death would deliver him to ‘paradice.’
The final two ciphers are dramatically shorter at just 13 and 32 characters – and have long been viewed as mathematically too concise to be solved with any certainty using cryptography alone.
Now, investigative consultant Alex Baber believes he has done it.
In a world exclusive, the Daily Mail has just revealed Baber’s conclusion that one man is responsible for two of the most notorious unsolved crimes in history: the Zodiac killer’s spree in the Bay Area in the late-1960s; and the horrific murder and mutilation of Elizabeth Short, the Black Dahlia, in Los Angeles in 1947.
Short, a 22-year-old aspiring actress, was found bisected above the waist and carefully posed in a vacant lot in the Leimert Park area, a grim discovery that sparked a media frenzy and cemented the case as one of America’s most enduring mysteries.
Marvin Margolis was unmasked when Baber deciphered Z13 recently, revealing the killer’s name – his alias of Marvin Merrill – for the first time.
Baber then also found a connection between the two cases in his proposed solution to the only other unsolved Zodiac cipher, Z32.
From there, he has unearthed what he describes as a wealth of circumstantial evidence tying this suspect, who died in 1993, to both cases.
Elizabeth Short, the Black Dahlia, was found murdered and mutilated in Los Angeles in January 1947
Short, a 22-year-old aspiring actress, was found bisected above the waist and carefully posed in a vacant lot in the Leimert Park area. Police are seen at the gruesome scene
Having been diagnosed with autism as a child, Baber believes he has an ability to process information and approach things in a unique, atypical way. This, coupled with his personal desire to bring closure to victims’ families and his experience of crime and tragedy in his own family, led him to launch the Cold Case Consultants of America, an independent organization dedicated to helping solve cold cases.
As well as sharing his investigation with the Daily Mail – which has spent months reviewing his findings – Baber’s theory is also the focus of a new website and podcast, Killer in the Code, coming out soon.
‘My name is —’
Baber explained two reasons why he believes he could crack Z13 and achieve what some of the finest minds in the world have long failed to do.
First, the Z340 cipher was solved in 2020, providing more insight into the Zodiac’s encryption methods and confirming that he was willing to stack different classical techniques on top of each other.
And second, US Census records for 1950 were made public three years ago, providing a complete dataset of names available for the first time. Baber realized that the killer’s identity had to lie within those records.
Combined with advancements in AI technology, he was able to narrow down billions of potential solutions to land on just one name.
The Zodiac’s other ciphers had involved placing symbols in a grid of orderly rows and columns.
And Baber figured that if the Zodiac had written his true identity in the cipher – as he said he had – it would contain a first and last name. From this, he assumed that the code consisted of two parts.
This was supported by the 13 characters forming a symmetrical pattern of symbols and alphabetical-style characters between the left and right side.
So he tried splitting Z13 into two lines, placing the last seven characters in reverse order on a second row, and adding a blank space to the first row, creating a two-by-seven grid.
The choice to add a blank space and to reverse the order of the second row was not arbitrary – it followed the same classic cryptography methods the Zodiac had used in the Z340.
‘When I went over the methodology behind the Z340 cipher, it planted a seed in my mind,’ he explained.
In the Z340, the Zodiac used homophonic substitution (where a letter is replaced by one of several different letters or symbols) and transposition (where the characters are rearranged into another order).
This gave Baber an idea: ‘If there were two encryptions layered within that cipher, what if he then scaled this down to the Z13 six months later?’
Because of the Z13’s length, a homophonic substitution method would be almost impossible to solve.
And so, analyzing the cipher’s structure, Baber identified which two encryption methods to apply: mono-alphabetic substitution – where each letter is consistently replaced by only one other letter or symbol – and columnar transposition – where the order of letters is rearranged in columns.
In Z13, several characters repeat: a distinctive figure-eight symbol appears three times and others feature twice resembling A, M and N. In a mono-alphabetic substitution, each repeated symbol must correspond to a repeated letter in the plaintext.
When he began the process, Baber found around 330 billion possible arrangements of repeated English language letters. However, many of these were nonsensical, being neither real words or names.
Using AI, he took the 1950 Census records and whittled them down to only real names that matched the repeated characters.
Alex Baber believes he has solved the Z13 cipher using classic cryptography methodologies, newly-released Census data and AI
Baber shares how he decrypted the Z13 cipher, revealing the name of a suspect: Marvin Merrill
It was a breakthrough that the Zodiac, devising his cipher in 1970, could never have anticipated.
‘Now we have AI, we’re able to process a lot of data, a lot quicker, all at once. Traditionally, this couldn’t have been done by hand,’ said Baber. ‘They couldn’t have sat down and calculated this because there are just too many numbers. But technology allowed us to do that.’
By ‘us’, Baber was referring to the Cold Case Consultants of America, a small investigative organization he co-founded that revisits unsolved crimes using public records, open-source material and modern analytical tools.
Baber also sourced the Social Security Administration birth records for male names and surnames and cross-referenced those with the 1950 Census records.
The pool of potential names was narrowed down and down to 11 million to 880,000 to 80,000 until he was eventually left with just 35 people.
From there, they were analyzed against the profile of the Zodiac killer from witness statements and investigative records: a white male aged between 35 and 55, 5ft 8in to 6ft 2in tall and based in or connected to California at the time of the attacks. This profile, Baber explained, came from the San Francisco Police Department’s description on the composite sketch and witness statements from the Zodiac’s last confirmed attack in Presidio Heights – the only witness descriptions widely regarded as credible given that this was the one time that people clearly saw the killer’s face and three separate groups gave similar descriptions that night.
Only one name matched: Marvin Merrill. It was not a name ever before linked to the Zodiac case.
‘I had no idea who this guy was. He was just another name,’ Baber said.
The Zodiac killer sent a string of letters to the media boasting of his depraved crimes and goading police
But when he dug deeper, Baber made a shocking discovery: Merrill was an alias. His real identity was Marvin Margolis, a man who had once been a prime suspect in the Black Dahlia murder.
‘It was overwhelming,’ Baber said, of the moment he realized that the two cases could be connected.
‘This is what everybody’s been waiting for – for 79 years in Elizabeth Short’s case and 56 years for the Zodiac case – and it’s all merged in one moment.’
Of course, several others have claimed to have solved Z13 and unmasked the Zodiac’s true identity. In recent years, former LAPD homicide detective Steve Hodel claimed that the Zodiac killer and Black Dahlia murderer were the same person, fingering his own father, George Hodel, for both crimes.
What sets Baber’s theory apart is the extent of the circumstantial evidence connecting his suspect to both cases, the fact his findings have gained the attention of active law enforcement agencies and that his cryptographic analysis and investigation have been backed by retired detectives and respected experts.
Among them is Ed Giorgio, one of the world’s most highly regarded cryptographers, a 30-year veteran of the National Security Agency and the only person to have served as both the Chief US codemaker and Chief US codebreaker at the NSA.
Giorgio has studied the Zodiac ciphers for years, testing numerous attempted solutions without endorsing any, and stressing that Z13 and Z32 are too short to yield a single conclusive answer through cryptography alone.
Solving the Zodiac’s remaining ciphers has been something of a personal challenge for him over the years.
‘I always said I was going to work on Z340 in my retirement. When I retired, I was still working full time so didn’t have a lot of time for it but I thought I made a lot of progress and I’ve written a lot of software on the ciphers,’ Giorgio told the Daily Mail.
Marvin Margolis is seen in a high school yearbook photo (left) and a photo obtained and enhanced by Baber. Baber’s solution to the Z13 cipher reveals the name Marvin Merrill. This was an alias for Marvin Margolis, a man who was a prime suspect in the Black Dahlia murder
‘Then, in 2020, a team solved it, which was an enormous contribution from them,’ he said, before adding: ‘I was very happy for them but I was a little disappointed that I didn’t do it.’
While solving the Zodiac’s ciphers was a major objective for him, Giorgio said he ‘always disregarded finding a solution for Z13 because it is too short’.
But now, he told the Daily Mail that, based on both the cipher solution and the totality of circumstantial evidence pointing to Merrill, he agrees that Baber has solved the Z13.
Using his own cryptography software, Giorgio has checked Baber’s process for decrypting Z13 and confirmed that the classical methods were consistent with those used by experts at the time of the Zodiac’s crimes, such as those that Margolis’s former roommate and friend Bill Robinson would have been familiar with from his stint in the Army’s codebreaking division.
The methods, he said, were ‘plausible’ based on those applied in the Zodiac’s other solved ciphers, leading him to confirm Merrill as a possible answer.
Giorgio explained that a cracked cipher typically produced a single, unmistakable ‘a-ha’ moment but cautioned that the brevity of Z13 meant that there could be multiple potential solutions resulting from different means.
To determine if any Z13 solution is correct, the cipher must not be looked at in isolation but rather within the context of other evidence, Giorgio said.
‘There’s no way you’re going to get conclusive evidence from the cryptography alone that Marvin Merrill is the guy. However, given the prior information about him that comes from the police reports and other non-cryptographic evidence, I would conclude [Baber] is correct.’
Giorgio has examined other decryption attempts and found that some have also reached plausible solutions but believes that Baber’s investigation is different.
‘When Alex showed me his findings, I came away thinking about the forensic evidence, not the cryptographic evidence… all those pieces of evidence in combination make you quite confident,’ he said.
‘It’s all about putting together lots of pieces of evidence – because no single piece of evidence is a smoking gun.’
‘Elizabeth’ as the clue
Incredibly, there may even be a link between the Zodiac killings and that of Black Dahlia hidden within the Z13 cipher itself – one that further supports Baber’s theory.
Sometimes ciphers have a ‘crib’, a clue or keyword woven into the encryption that helps unlock it.
When asked to review Baber’s solution to Z13, Ireland-based cryptographer Patrick Henry made another shocking discovery: the crib for Z13 could be ‘Elizabeth’, the first name of the Black Dahlia victim.
Baber has also decrypted the Zodiac’s Z32 cipher, finding a solution that links to the murder of the Black Dahlia
The Z340 cipher was finally solved by a team of international codebreakers in 2020 – more than half a century after the Zodiac sent it
Henry first numbered each of the letters in ‘Elizabeth’ in the order they appear in the alphabet, with A being 1, B being 2, E being 3, and so on.
He then numbered the letters in Baber’s two-by-seven grid containing the name ‘Marvin Merrill’ by their corresponding columns, so that both names shared a numbering pattern (the two initial Ms are 1, the ‘a’ of ‘Marvin’ and ‘e’ of ‘Merrill’ are 2, and so on).
Next, he rearranged the numbered ‘Marvin Merrill’ letters in their columns to match the order dictated by the letters in ‘Elizabeth’.
Working backwards through Baber’s decryption process, the rearranged grid collapsed into a single 13-character line – precisely that of the original Z13 configuration, suggesting that the Zodiac killer may have embedded the first victim’s identity into his code two decades later.
As for the Z32 cipher, it has gone unsolved since being sent to the San Francisco Chronicle on June 26, 1970.
The Zodiac’s letter containing the 32-character code also included a roadmap of the Bay Area with a crosshair symbol drawn over the peak of Mount Diablo, and the instruction: ‘0 is to be set to Mag. N’.
‘The map coupled with this code will tell you where the bomb is set,’ he wrote. The ‘bomb’ appeared to refer to the Z13 letter and another which both contained black ink drawings of explosive devices.
A month later, on July 26, the killer sent another letter, with the message: ‘PS. The Mt. Diablo Code concerns Radians & # inches along the radians.’
Baber also claims to have discovered a solution to the last remaining cipher, Z32, and is now awaiting independent verification that it does, as he believes, provide a direct link between Zodiac and the Black Dahlia murder.
After Baber cracked both ciphers, he launched his full-scale investigation into Margolis/Merrill, uncovering what he considers to be overwhelming evidence proving that one man was responsible for two of the biggest unsolved crimes in American history.
The investigation is also being developed as a premium documentary series by Emmy Award winning producers Melanie Capacia Johnson and Jonathan Reynaga, in collaboration with Baber, through TH Studios
