Seems there isn’t much activity on these forums, but made this GIF image.  Not sure if it will work here, but I attached it.

Haven’t had much luck sharing this solution around the Zodiac related forums so far, but will branch out to Reddit and the broader True Crime community next I suppose.

I do have some experience with Youtube and have a channel with 15k subscribers, but that audience wouldn’t be interested in Zodiac related content, so I will probably go the video route to raise awareness to the general public.

Still, I will keep an eye around here and see if there are any signs of life.

Hi! Just to clarify, I’m not a cryptographer or a specialist in this field.

In general I’m a bit skeptical about homophonic-style interpretations applied to very short ciphers like Z32, because the number of possible solutions can become quite large and it’s often easy to find readings that seem plausible.

That said, I have to say the proposed solution looks carefully constructed and well explained. I especially appreciated that the reasoning is presented step by step: the initial assumptions are clearly stated, a search space is defined, and then several constraints are applied, both cryptographic and geographic. In my opinion this already makes it more interesting than many other solutions that simply propose a plaintext without really showing how it was derived.

At the same time I wonder whether the final selection might rely a bit too much on geographic elements interpreted after the fact (triangles, alignments, proximity to certain points, etc.). This could make it easier to see patterns even when they might simply be coincidences.

It would also be interesting to better understand what the triangle identified on the ground actually is: a natural depression or something artificial. Understanding its nature could already help evaluate how meaningful this correspondence really is.

In any case, even if it ultimately turns out not to be the correct solution, I think the method used is still interesting and worth discussing.

Have a nice day!

@lendor-77 Hi there,

Thanks for taking the time to leave a comment.  I wasn’t sure if people were still around here.  

Ground penetrating radar of this triangle is specifically what I am hoping will happen.  That would prove if something is buried within that triangle.

“In general I’m a bit skeptical about homophonic-style interpretations applied to very short ciphers like Z32, because the number of possible solutions can become quite large and it’s often easy to find readings that seem plausible.”

Yes, this is true.  I tested two million possibilities with this code, as described in the paper.  After filtering by the constraints, only 54 remain of those two million.  They are then ranked by proximity to known Zodiac crime scenes.  IN THREE AND THREE EIGHTHS RADIANS TEN is the top ranked candidate of the two million different combinations of radians and inches coordinates.

“That said, I have to say the proposed solution looks carefully constructed and well explained. I especially appreciated that the reasoning is presented step by step: the initial assumptions are clearly stated, a search space is defined, and then several constraints are applied, both cryptographic and geographic. In my opinion this already makes it more interesting than many other solutions that simply propose a plaintext without really showing how it was derived.”

I appreciate these kind words.  Quite a bit of thought went into this, although I am still planning a third version of this paper.  I would like to improve certain sections.  I think there is still room for improvement.

“At the same time I wonder whether the final selection might rely a bit too much on geographic elements interpreted after the fact (triangles, alignments, proximity to certain points, etc.). This could make it easier to see patterns even when they might simply be coincidences.”

The geographic elements were noticed after decryption, and do not play a role in the decryption process.  The geometry depicted is created by the Zodiac’s crime scenes, and Mt. Diablo, they were pre-existing geographic facts.  I simply drew lines on the point to highlight the geometry that he had already created.  The paper can still exist without the geometry being mentioned at all, but I chose to include it because he created it himself, and I am just highlighting that.  The solution does fall within a significant region of this pre-existing, Zodiac created geometry.  

“It would also be interesting to better understand what the triangle identified on the ground actually is: a natural depression or something artificial. Understanding its nature could already help evaluate how meaningful this correspondence really is.”

Equilateral triangle shapes do not typically occur naturally.  And this one also points North.  I do not think that is a natural coincidence.  

“In any case, even if it ultimately turns out not to be the correct solution, I think the method used is still interesting and worth discussing.”

Thank you, lendor.77.  I am happy to talk more about this as well.

I understand that it’s nice to receive feedback after putting so much work into a solution, especially when it’s well documented.
I’m just sorry that I’m probably not the best person to give a truly objective or professional opinion! 🙂

@lendor-77 No problem, I am just glad to chat about it.

I do hope they radar it.  It is cheap, fast, and non-invasive.  Doesn’t require any digging to know if something is buried there. If there is evidence there, it is important that it is checked out.  A simple scan can rule it out. 

I have reported the decrypted coordinates to authorities, maybe they will take a quick look at their convenience.  Low effort, high reward if they do find something.  It could help move the case forward.

I will add that over the past 3 and half months, I have had a few qualified experts that have been kind enough to review the work and respond.  They did not point out any critical flaws in the code or methodology, and I am still waiting to hear back from quite a few of them.

It has been difficult to receive proper feedback so far, as there have been many subjective solutions presented in the past.  I was not a member of the Zodiac community before December 2025, when I joined the Zodiac Killer forums to share my work.  I was surprised to learn after the fact that I had seemed to be the first person to use a computer to solve this cipher.

But when I came here, I saw the user Oliv92 had taken a very similar approach five years ago, but was missing a critical final step.  This user actually received only a single response to their solid work.  I have reached out to them on Youtube, to hopefully let them know that they were very close, and were ignored it seems.  Most users were more interested in the subjective approach from the French engineer, as it was more popular in that year.

I had a similar bad timing event when I shared mine, as the Black Dahlia rumor went wild among the Zodiac community the very next day, and most were very interested in that rumor.

Still, hoping the triangle gets scanned in case something is there.  The math works out nicely on this one.

After joining the Zodiac Killer forums to share my work, which was a significant effort that involved additional research after decryption, a few users on those forums that were very familiar with this case did show interest, and I had some nice conversations on there via private messages.  I shared the Vallejo 1968-1969 City Directory for community members doing research into this case on those forums as well.

During my relatively short time on there, I received multiple messages from the forum administrator demanding that I pay them 10 dollars to keep sharing my findings with others.  This is the first time I have seen this happen during my time on the internet, which is almost 30 years.  I didn’t feel comfortable supporting their monetization of the Zodiac case, so I refused to pay.

It has been quite a saga getting the information out there, but I will keep trying.  I’m not a social media user, so that has made it harder for me to share it more broadly.

Posted by: @coder1987

↑

Hi everyone,

I am sharing my whitepaper that details a computational methodology to solving Z32.  The code is also publicly available.

Paper:  https://zenodo.org/records/18645227

Code: https://github.com/dstampher/zodiac-z32-cipher

…

-David

Hi David.

Thanks for this.

So, perhaps it was one specific detail in your approach that has piqued my interest in the work you present here. As you say in your Github README:

The primary solution: IN THREE AND THREE EIGHTHS RADIANS TEN

Measuring 3⅜ inches along the 10 o’clock radial from Mount Diablo points to … .

What I particularly like about this is how, despite the wording of your primary solution, you have allowed yourself to move away from the age-old distraction of believing, unquestionably, that we need to be thinking about angles in actual radian measure. Of course, we actually don’t have to do any such thing.

Whether through misunderstanding, an attempt to deceive, or merely a use of the word ‘radian’ derived, with some alternative meaning,  from some specialised field, it is clear that The Zodiac’s solution concerns “radia[l]s and inches along the radia[l].” In your work you divide the diablo ‘compass’ as you would a clock, into twelve, and your ‘radials’ are the hours.

This is a good approach, only … what you then would expect to see in the solution are 1.) a distance in “INCHES” 2.) and an ‘angle’ in “HOURS.”

The word “RADIANS” which I (and, perhaps, you also) take to imply merely “RADIAl directioNS” shouldn’t be expected in the solution at all.

@shaqmeister Hi shaqmeister, thanks for the comment.  Love the name by the way, and saw you in the Oliv92 thread from 5 years ago.  You were the only one that engaged with them, and I salute you for that.

“The word “RADIANS” which I (and, perhaps, you also) take to imply merely “RADIAl directioNS” shouldn’t be expected in the solution at all.” I included a section in the paper specifically addressing this.  Zodiac did misuse the term “radians”. 

I did expect to find some variation of the word “RADIANS”, which is why the code also tests “RADIAN”, “RAD”, and “RADS”.  The reason for this, was the postscript hint that he gave, which is quite explicit.

His misuse of the term is consistent with past observed behavior, including misspelling the word “Christmas”, and the errors made in his other ciphers.

The nice thing about this proposed, unconfirmed solution is that it points to a location that can be physically verified, so this one is actually falsifiable, which is rare.  The other part that I like is that it is derived objectively with mathematics. 

We could even say that Zodiac himself cherry picked this solution, as the ranking algorithm for the survivors is proximity to known Zodiac activity.  Blue Rock Springs was the one. 

From the tallest hill near the triangular anomaly, where the Somerset Water Tanks are located, he can see that crime scene.  The triangle is just slightly over a mile away.

Thanks again for the comment, I am glad to see that people actually are still around here.  I wasn’t sure if everyone had given up on this cipher.

It’s been quite some while since I was last giving thought to the Zodiac case, so I appreciate I may be out of touch with some of the details. From what I remember, however – and please correct me if I’m wrong – wasn’t the whole purpose of the Z32 code to guide LE to a bomb dug into a hill alongside a road along which a school bus would be regularly travelling? Surely, then, we must be ready to reject any such proposal that doesn’t meet these basic criteria?

Posted by: @coder1987

↑

“The word “RADIANS” which I (and, perhaps, you also) take to imply merely “RADIAl directioNS” shouldn’t be expected in the solution at all.” I included a section in the paper specifically addressing this.  Zodiac did misuse the term “radians”. 

Thanks for directing me to where you discuss this in your paper. And, yes … I can agree with all that write there.

Posted by: @coder1987

↑

I did expect to find some variation of the word “RADIANS”, which is why the code also tests “RADIAN”, “RAD”, and “RADS”.  The reason for this, was the postscript hint that he gave, which is quite explicit.

Just so I can be sure I’m not misunderstanding you, can you reference exactly what you are referring to as the “postscript hint” and why you think this requires that some variation of the word “RADIANS” should appear in the solution?

If you are referring to what I believe you are referring to, then I would argue that the solution merely “concerns” what he gives us to follow, without any such requirement that it must contain specific terms.

@shaqmeister Hi again,

I’ve attached an image of part the Zodiacs “Death Machine” schematic, an image from Google Street View from LHR looking towards the triangle location, and a topographic map.

This is not presented as definitive proof, although the roadside depression he depicted, and the prominent hills are definitely there.  

“From what I remember, however – and please correct me if I’m wrong – wasn’t the whole purpose of the Z32 code to guide LE to a bomb dug into a hill alongside a road along which a school bus would be regularly travelling?”

This is true, but I make no claim in the paper as to what might be buried there.  While he said he would place a bomb there, that does not mean he actually did, and so I don’t speculate as to what may be buried within this triangle.  There are other possibilities about what could potentially be buried here, but it probably won’t add much value if I guess.  

Regarding LHR being a bus route, I do not know if all schools in Vallejo, some of which no longer exist, have their bus routes from 1968 published on the internet.  It does seem that some students that were located in this more rural area of Vallejo, would require bus transportation, but I do not have records that prove this.

I don’t think the unconfirmed bus route status of LHR in 1968 invalidates the rest of the paper, as buses can still travel on roads that are not officially bus routes.  Still, you raise a valid point that I had also considered early on.

I will say, the ingredients that Zodiac listed for his “Death Machine” are actually dangerous when mixed.  I’d rather not repeat them, but he indicated he actually did have some technical knowledge to construct a bomb. 

While his design seemed absurd, and it is, the dangerous chemistry of the ingredients he mentioned was correct, albeit simple. 

Worth mentioning he used triangulation in his triggering mechanism of his “Death Machine”.  When I decrypted the “radians” + inches coordinates, I had to triangulate them to land by the triangle anomaly.

Another interesting thing that I found regarding his apparent obsession with triangles is his first cipher, Z408.

In his first cipher, the first encrypted symbol that Zodiac uses, of all possible symbols, in his cipher writing career is….

A triangle.

But not just any triangle.  A hollow triangle.  The same hollow triangle that he repeats in Z32, and ends the cipher with.

Stating facts, but uncertain if intentional or coincidence.

This hollow triangle reminds me of the triangle by LHR, so I overlaid it on top, and that is my profile picture.

Posted by: @coder1987

Posted by: @shaqmeister

“From what I remember, however – and please correct me if I’m wrong – wasn’t the whole purpose of the Z32 code to guide LE to a bomb dug into a hill alongside a road along which a school bus would be regularly travelling?”

This is true, but I make no claim in the paper as to what might be buried there.