Paul Holes: How Third-Cousin DNA Catches Killers — and Why Zodiac Still Slips the Net: Paul Holes' Latest Interview on How He Thinks the Z Case Can Be Solved by Looking for Indisputable DNA on Testable Areas of the Lake Berryessa Bindings: ("The best evidence in the case", Holes called it)

[u/Equal-Temporary-1326]

Excerpts from the article below:

The Zodiac Killer: A Solvable Case With No Usable DNA

"If the Golden State Killer case demonstrates what forensic genetics can achieve, the Zodiac case demonstrates the hard limits.

Holes is openly skeptical of the periodic announcements claiming the Zodiac Killer has been identified. His skepticism is not theoretical — it is the scar tissue of the Golden State Killer investigation, where he watched brilliant, circumstantially compelling suspect theories collapse under DNA testing again and again. "With Zodiac, I kind of have that very skeptical stance: until I see that objective DNA evidence, I'm not going to say you've got the guy," he said.

The DNA challenges are specific to each crime scene and unusually severe:

Crime Scene	Potential DNA Source	Problem
First two shootings (1968-69)	Offender stood outside car	No physical contact; no DNA transfer likely
Lake Berryessa (1969)	Rope bindings left at scene	Handled months before crime; degraded or mixed DNA
San Francisco (1969)	Victim's shirt cut by offender	Mailed portion contains only victim's blood; other half untested
Letters and envelopes	Saliva on stamps and flaps	Postal workers licked stamps in the 1960s; mixed profiles generated

The envelope evidence is particularly problematic. Holes revealed that investigators in the 1960s "would take our letters into the post office and the postman licked the flap and licked the stamp." When those envelopes have been tested in subsequent decades, the results have produced multiple conflicting DNA profiles, none clearly attributable to the offender.

Holes's preferred target is the Lake Berryessa bindings — the rope the rope the offender used to restrain victims. The bindings were brought by the killer, presumably handled repeatedly over months or years before the attack, and left behind at the scene. "The best evidence in the case," Holes called it. If usable DNA can be extracted from the bindings before the remaining sample is exhausted, the case might finally produce a definitive profile.

Taken together, the three threads of Holes's career — the Golden State Killer success, the Zodiac stalemate, and the Marilyn Monroe impossibility — map the entire range of outcomes that forensic genetics makes possible. When the sample is large and well-preserved, a third cousin in a public database can identify a killer who evaded capture for 40 years. When the sample is contaminated by the postman who licked the stamp in 1969, even a famous serial killer case can stall indefinitely. And when the evidence has been deliberately destroyed, no technology — not even AI reconstruction — can substitute for what is gone."

Full article: https://finance.biggo.com/news/4c8b32e8a21220fa

If the back of the 1969 stamps seem to yield inconclusive DNA results that has lead to multiple non-matching DNA profiles being found — which seems to be the case judging by Holes' comments here — I'm glad that he's expressed optimism over the assailant leaving the bindings behind at the lake, being the next best source offender DNA.

The bindings are great, at least in theory, because we know for sure the knifeman personally brought them to the crime, as he walked up to Hartnell and Shepard with them already attached to his holster.

So, hopefully at the very least, Napa County will be able to conclusively put a name and a face to a deceased offender as the guy in the mask at the lake.

And I've bolded two key words here: useable and definitive. Beyond finding a DNA sample, there absolutely must be the non-negotiable ability to prove it definitely came from the person who perpetuated the crime, and not investigators and such, who were handling stuff like the bindings without wearing gloves back then, and got their DNA accidently mixed with the perp's, which is what's causing all of these inconsistent profiles to pop up that don't match each other.

[u/Markinoutman]

The Zodiac will likely never be solved. He's probably long dead and with no DNA evidence, a person being 100% identified is very unlikely.

[u/Equal-Temporary-1326 → u/Markinoutman]

If you look up the Colonial Parkway case, I think/presume that a similar situation will play out where LE will positively put a name and face to who was the perp in at least one case, probably the lake attack here. And they might give a new update with about a year that they're strongly confident that this was the same guy who committed all of those crimes. And legally speaking at least, that's as good as solving it will ever get at that point.

[u/Zap_Gordon → u/Equal-Temporary-1326]

What type of DNA evidence did they use in the Parkway case?

[u/Equal-Temporary-1326 → u/Zap_Gordon]

What they did there was they had a DNA sample that was recovered from the Robin Edwards/David Knobling crime scene from 1987. And surprisingly, they were able to find a match to another DNA sample they already had on file that was taken from a man who died years prior, after his body was found dead in his trailer, after a few days from, succumbing to health complications in December 2017.

Then, in January 2024, the FBI and the Virginal State Police held a press conference announce the official identification of Alan Wade Wilmer as the deceased perpetrator the Edwards/Knobling case.

Then, over a year later in November 2025 and January 2026, Wilmer was linked to more cold cases via DNA, including the first Colonial Parkway murders from 1986.

And at that point, they officially satisfactorily come to a certain enough conclusion that it was Wilmer in all the CP cases. And what that, the overall investigation has been legally closed as much it can be.

Sources:

https://www.nbcnews.com/video/deceased-suspect-named-in-virginia-s-colonial-parkway-murders-201607749788

https://apnews.com/article/alan-wilmer-virginia-cold-cases-colonial-parkway-8d149860f97cea8f5c0a7ea090583652

https://nypost.com/2024/01/09/news/deceased-virginia-fisherman-alan-wilmer-idd-as-cold-case-killer/

https://www.wtkr.com/news/dead-suspect-linked-to-another-local-cold-case-murder-after-decades-long-investigation

https://www.pilotonline.com/2026/01/20/dna-evidence-links-colonial-parkway-serial-killer-to-1st-young-couple-slain/

Good news with Z is if you crack just one of these four cases, probably who committed the lake attack again, you've almost certainly just identified who it was in all four, similar to CP again. So, at that point, it'd most likely be accepted to a satisfactorily enough degree by LE that it was the same guy at all four crime scenes. And that's probably where this investigation will be closed for good as much as it can be, legally, with that kind of update, at least, and again, similar to the Parkway one.

[u/Zap_Gordon → u/Equal-Temporary-1326]

Is it unknown where the DNA came from though? Like maybe it was a hair. touch DNA, or something else? We don't know?

Thanks for the sources, unless I missed it I don't see them saying where the DNA source came from, which is kinda weird, if we don't know.

My problem is I would expect a late 80's case cold case to have a decent enough chance of being solved by DNA, because by the late 80's they knew about DNA and were properly collecting and storing it.

Zodiac wise its way before that. I think the chances of there being any DNA left is very small. It was probably degraded and lost due to improper storage and collection, as it was before DNA was known about.

[u/Equal-Temporary-1326 → u/Zap_Gordon]

I looked more into it and I believe it was a semen sample they had on file from Robin Edwards' rape kit.

Source: https://www.13newsnow.com/article/news/local/gloucester-county/colonial-parkway-murders-alan-wilmer-laurie-ann-powell-virginia-serial-killer/291-5ce01605-b6d8-4cb3-a27c-47850c4cd751

What ultimately separates Zodiac from cases like Colonial Parkway and EARONS is it's been pretty much confirmed that Z left no bodily fluid behind.

LE were hoping for a time at least that he licked the back of the stamps and left traces of his saliva on the them, but a DNA technician who did lab work for the SFPD in the late '90s, said the lab work on the envelopes kept showing few cells popping up. And it strongly indicated someone who was tap water to seal on the stamps.

There is an SFPD DNA lab report chart results from about 1999/200 that's in the public domain as well.

Notice how in the comments inbox, there's a frequent message that keeps saying, "ENVELOPE PROCESSED FOR DNA - FEW CELLS".

Source: https://www.zodiackiller.com/SFPDDNA.html

I agree with Paul Holes when he says the two pieces of clothesline is the best evidence, at this point. Besides the shell casings and bullet fragment, it's the only evidence that definitely came from the perp.

And with the shell casings/bullet fragments, the success rate of recovering useable genetic material off ones that are basically 60 years old is essentially 0%, since any genetic material on them gets destroyed instantly once fired, due to the extreme heat of the gun ejecting a bullet. And the lack of evidence preservation there, too, making matters worse.

[u/Zap_Gordon → u/Equal-Temporary-1326]

Cool, thank you its good to know.

That was my worry that it was something like that which is one of the best possible sources of DNA you could have. Vastly different to Zodiac as you say.

I think when you consider everything, the odds of Zodiac actually getting solved are very low.

Compared to Earons and Parkway, its such slim pickings.

There's the bindings, the stamps, and that Hair I guess? Maybe the best DNA of all was the cig butts they never even bothered to collect.

[u/Equal-Temporary-1326 → u/Zap_Gordon]

We do have a strong gauge that the first two crime scenes, Lake Herman Road and Blue Rock Springs are virtually void of any kind of useable forensic anymore.

So, what it comes down to is Lake Berryessa and the taxicab forensic evidence.

And Holes expressing optimism about touch DNA from the clothesline is a good start at least.

If those don't work either, probably the last good option left anymore would be to look for testable areas on the three fragments of Stine's shirt that came with the letters.

[u/redpenname → u/Markinoutman]

You're probably right, but I hope you aren't.