DNA Analysis

Zodiackiller.com Message Board: General Zodiac Discussion: DNA Analysis

By Tom Voigt (Admin) (12-224-139-118.client.attbi.com - on Friday, October 18, 2002 - 12:47 am:

Did anyone else notice that during ABC's Primetime Thursday episode on Oct. 17, Dr. Cydne Holt wasn't wearing a hairnet when analyzing the Zodiac letters? I almost expected her to determine that Zodiac was a white, 30-something female with long reddish hair...

By Tom Voigt (Admin) (12-224-139-118.client.attbi.com - on Friday, October 18, 2002 - 12:48 am:

By the way, Dr. Cydne has my vote as the first-ever "Zodiac hottie."

By Peter H (Peter_H) (dialup- - on Friday, October 18, 2002 - 02:02 am:

I thought Sandy had that distinction. In fact, Tom, and I believe Howard and Ed are my sources on that. Or are you recanting (or blacking out on) your testimony from the Riverside trip?

By Tom Voigt (Tom_Voigt) (12-224-139-118.client.attbi.com - on Friday, October 18, 2002 - 02:11 am:

To qualify as a "Zodiac hottie," one must be a law-enforcement type. Otherwise, Sandy, Kendra, Chal, Victoria, Dianne, Howard and Roger would surely tie. And Scott.

By Peter H (Peter_H) (dialup- - on Friday, October 18, 2002 - 02:34 am:

Toschi will be crushed.

By Chalandra (Chalandra) (ac9ce5f9.ipt.aol.com - on Friday, October 18, 2002 - 05:47 am:

Thanks Tom!

By Socal (Socal) (66-27-106-7.san.rr.com - on Friday, October 18, 2002 - 06:40 am:

I am sure it was a great show last night, to bad the power went out in my part of San Diego half way thru it. I saw the first 30 minutes and the last 5 minutes.

By Roger Redding (Roger_Redding) (sdn-ap-008txhousp0068.dialsprint.net - on Friday, October 18, 2002 - 09:01 am:

Why Tom, I never knew you cared.
I would guess that some of the scenes with Dr. Hott were staged, possibly including the denouement ("Cydne, when we come to Collins, could you go back to your office to check on something?"). In one scene she was working in what looked like her living room.
I would also guess that more than three samples were compared. They chose to show Allen's for obvious reasons, Q's because they had been following Rodelli around for a year and had to do something with that, and Collins' because of Dr. Hottt's melodramatic hesitation (if that wasn't staged).

And another thing: having seen Dr. Hotttt and met Dianne, I wonder what they do in California when unattractive women apply to be DNA experts? Say, "Sorry, but you might have to be on TV someday, and, well, we have to make a good presentation"?

And finally, isn't Howard's hair kind of reddish-blond? These things alway raise more questions than they answer.


By steve merritt (Cashflagg) (ip64-48-108-250.z108-48-64.customer.algx.net - on Friday, October 18, 2002 - 10:24 am:

The whole thing was stink-o-rama! The staging of the Collins DNA sample…correct me if I'm wrong, but they have a PARTIAL DNA composite from the stamps on one of the letters. Prior to looking at SFBM's DNA profile, Dr. Hottttttt says that she has studied the zodiac DNA so much she can give it a cursory glance and tell if it's a match. She looks at the Collins DNA and runs back her desks and then, it approx. 4 seconds comes back and says NOPE!

Man, if it's that freakin’ easy to check DNA, they should have this wrapped before Halloween.

The reporter called Betty Lou Jensen Mary Lou and at one point referred to the LB crime as a shooting. One year investigation? Man am I ever glad they’re on the case. And they refer to us as “armchair detectives”… people on this board could have de-bunked their theories for them. Primetime. Slimetime.


By Kendra (Kendra) (pluto.cds1.net - on Friday, October 18, 2002 - 01:11 pm:

I figured that the recent hub-bub about Z's DNA from the stamp was due to the then-upcoming Primetime special. Primetime was behind it all...

In that light, I wonder if DNA testing will continue with other suspects, without Primetime's authority or $$$. It must be very costly to do all of this DNA analysis, so I wouldn't be surprised if, from now on, testing will be on the slow side, if at all. Ed, I agree that Davis and Kacyinsky should be tested. The other "top" suspects should be tested as well. However, if nothing pans out from them, I doubt that any of the lesser known suspects would have a chance to be compared due to the high cost of testing.

By Douglas Oswell (Dowland) (149.philadelphia01rh.15.pa.dial-access.att.net - on Friday, October 18, 2002 - 05:01 pm:

DNA testing is difficult only in the stage where the sample is collected and processed. Once the samples are typed, comparisons are fairly simple. I'm sure the reason Dr. Holt had to go back to check her records is because she simply couldn't remember the various types of all the different patterns off the top of her head. Of course some of the patterns would be easy to remember, and apply to a particular suspect. Consider blood typing, for example. If your unsub is type A, and your suspect is B, you know right away that the suspect isn't a match, because an A blood type can either be AA or AO, but nothing else.

By Jake (Jake) (cache-mtc-ak04.proxy.aol.com - on Friday, October 18, 2002 - 06:34 pm:

Tom Wrote:
"By the way, Dr. Cydne has my vote as the first-ever 'Zodiac hottie.'"

I've got a thing for redheads, sure, but doesn't anybody else think Lt. JoAnne West had that certain something???


By Ed N. (Ed_N) (acadd315.ipt.aol.com - on Saturday, October 19, 2002 - 12:07 am:

Can I get Dr. Hottttttttt to test my DNA to see if I'm Z, just in case???

By Scott Bullock (Scott_Bullock) (cache-ntc-af07.proxy.aol.com - on Saturday, October 19, 2002 - 06:57 am:

So, I wasn't the only one who thought Dr. Holt was hot! Does she really run around the lab in a skirt with high heels?

Thanks for the compliment, Tom, but compared to the others that you mentioned, I look like a bucket full of elbows.

Also, I can't believe that ABC followed Rodelli around [or that they were able to get Q's DNA, for that matter] but ignored Doug and Howard's suspects. Seriously, Q [are we allowed to mention his name yet?] is the worst suspect I've ever run across in this case, even worse than Kenny's step-dad.

By Douglas Oswell (Dowland) (198.philadelphia01rh.15.pa.dial-access.att.net - on Saturday, October 19, 2002 - 08:26 am:

The problem with Rodelli's suspect is that people who do the kind of things that Zodiac did, for the reasons he did them, usually don't end up as prominent citizens of a major metropolis.

By Scott Bullock (Scott_Bullock) (cache-ntc-af07.proxy.aol.com - on Saturday, October 19, 2002 - 08:52 am:

I agree with that assessment 100%, Doug, and honestly hope that this DNA sample will be compared to TK's DNA ASAP.

By Douglas Oswell (Dowland) (116.philadelphia01rh.16.pa.dial-access.att.net - on Saturday, October 19, 2002 - 09:22 am:

I agree, Scott. Even if they have to get a warrant to get a sample, it shouldn't be a problem.

By Gregusjay (Gregusjay) (12-234-235-44.client.attbi.com - on Sunday, October 20, 2002 - 02:00 am:

I am surprised that the head-aches Z supposedly suffered from wasn't looked into more by the police as part of Z's MO. Seems to me Z may have suffered from severe migrains and practically begged Belli for help before he lost "controol"
of himself.
If that was Z's voice on Jim Dunbar's radio show, then Z seemed also seemed to sound fairly young. Mid twenties. This could explain his time in Riverside and close ties to the college there presumably as a student..
I'm just openly re-thinking....
Z a student in Riverside Community College..possible in the ROTC or enlists in the military afterwards, become's stationed in the Bay Area, possibly Mare Island..is somewhat of a loner, travels by himself a lot..dying for attention, possibly considering suicide as a way to stop head-aches, wants others to suffer as much or worse than he does..
any other ideas?

By Howard Davis (Howard) (dsl-pb-4550.linkline.com - on Sunday, October 20, 2002 - 02:03 am:

True,but in another place the reporter calls Jensen by her real first name.
They did say the Dripping Pen card was written/sent in the summer of 1969!

By Scott Bullock (Scott_Bullock) (cache-ntc-af07.proxy.aol.com - on Sunday, October 20, 2002 - 02:42 am:

Let's put it this way, Doug: In an ideal world, the next thing that I would do is see if I could corroborate the DNA sample with additional samples. Then, if all the samples matched, I'd rule out Allen entirely and focus on all of the other high profile suspects. You can bet your last dollar that if I were in charge of the situation, TK and Davis would be the next two suspects I'd test my corroborated sample against. However, as I stated elsewhere, if there isn't corroboration amongst the samples, all bets are off and Allen is as good a suspect [or better] as any.

It will be very interesting to see where the investigation goes from here. There was one distinction in the show that was of particular interest to me from the very start: Nobody within SFPD excluded Allen as a Zodiac suspect. Sure, they said that Allen could be excluded as the individual whose DNA was found beneath the stamp, but they never said, "Allen isn't the Zodiac." Essentially, as Ray N. has eloquently stated elsewhere, such a statement, even at this point, cannot be considered "factual." As I stated above, the sample must be corroborated by other samples that are identical to one another. If the sample that is now in SFPD's possession can't be found elsewhere, or is different from other samples that are found, then no suspect can be excluded based upon that one sample.

It may sound like I'm trying to cloud the issue but I really am not. Like it or not, that is the nature of the scientific method, so why even argue otherwise? As Ray N. and others have pointed out, there are other samples from other letters to which this sample can be compared that haven't been "discovered" yet.

So, the real question is, should SFPD spend their time, money, and other resources, to determine if the sample they have can be corroborated by other samples, or, should they use the sample they have and begin comparing it to other suspects? Honestly, my vote would go for the former.

By Linda (Linda) (208-59-124-144.s144.tnt1.frdr.md.dialup.rcn.com - on Sunday, October 20, 2002 - 06:48 am:

Scott... I have to agree, Dr. Holt herself indicated that the testing of the DNA ruled out the question that the three suspects profiled could NOT have been the ones that LICKED the stamps/envelopes...

What I would say is that samples of Davis' and Kaczynski's should be tested right now against the samples taken; if either one matches, then I think it could be concluded that the one matching was most assuredly involved in the Z crimes; if neither match, then I think we're back to square one with all of the suspects...

By Lapumo (Lapumo) (p51-236.as1.clm.clonmel.eircom.net - on Sunday, October 20, 2002 - 07:03 am:

You do touch on an interesting point Linda.Many now believe that this DNA result now eliminates Allen as the Zodiac.
Just to ask those with others suspects,if the test comes back negative in those cases also do you guys feel it would eliminate your suspects?
For those with no "favourite" suspect,is this now your Holy grail? Must the owner of this be Zodiac?

By Douglas Oswell (Dowland) (67.philadelphia05rh.16.pa.dial-access.att.net - on Sunday, October 20, 2002 - 07:34 am:

Let's put it this way: if DNA results came back negative on Kaczynski, it would put a definite damper on my enthusiasm for him as a suspect. I might still be inclined to study him in terms of typology because I would continue to believe that psychologically and criminologically he's a dead ringer for Zodiac.

By Jake (Jake) (cache-dr05.proxy.aol.com - on Sunday, October 20, 2002 - 07:40 am:

Doesn't anyone want to test the results against a certain Public Policy professor at Berkeley??? Right after Vic Tayback, of course. Hee hee!

Inserting earplugs against the impending chorus of "no's,"

By Chrissy Shaw (Chrissy_Shaw) (dialup- - on Sunday, October 20, 2002 - 11:22 am:

What I would hope is that(I include myself in this)if all tests are negative, that people will avoid dwelling on favorites regarding suspects. I fall in the same pattern here, because I am so certain a certain trait should be in the history of whoever z was or is. Everyone was so hot for the cab driver and/or the emt guy up here in the Green River cases. It turned out it was neither and it also turned out that a key part of the profile developed early on was correct, but not in others. I think I have found a couple directions not fully explored with the z cases, but at this point I would rather have others review things before I get too lost in my own convictions.

By Tom Voigt (Tom_Voigt) (12-224-139-118.client.attbi.com - on Sunday, October 20, 2002 - 11:37 am:

The caller to The Jim Dunbar Show was a Napa State Hospital patient named Eric Weir. He wasn't the Zodiac.

By Gregusjay (Gregusjay) (12-234-233-242.client.attbi.com - on Sunday, October 20, 2002 - 11:52 am:

Thanks Tom, I've always wondered why that point wasn't played on more. One would, unfortunately, have to second guess, anything Belli is involved in..(not that the caller was prompted by him) He was a grandstand lawyer who loved the limelight. I truly believe he had to be a descendent of P.T. Barnum. He certainly added a circus atmosphere to the Z investigation back when..
Thanks again for clearing things up Tom.

By Ray N (Ray_N) (sdn-ap-011scfairp0293.dialsprint.net - on Sunday, October 20, 2002 - 12:00 pm:


You put forth a recommendation that perfectly illustrates what I feel to be an instance of where using "common sense" leads us, at least potentially, in the wrong direction.

Specifically, you wrote: "What I would say is that samples of Davis' and Kaczynski's should be tested right now against the samples taken; if either one matches, then I think it could be concluded that the one matching was most assuredly involved in the Z crimes; if neither match, then I think we're back to square one with all of the suspects..."

The logic behind this is flawed because there is no possible way the sample available could be matched to any suspect. There are only 4 out of 9 alleles available. It is only able to rule out suspects at this point. Rule them out as not contributing that particular sample, not necessarily ruling them out as being Zodiac. I would suggest that John Quiniones and ABC are responsible for this. They sat there while Dr. Holt went back to her office and, although they didn't say it, the obvious effect created was that there was a possibility that she would come back and declare a match. Impossible. Think about how would feel if you were an innocent defendant and a couple of your genes happened to be the same as those on some perp's partial profile? Would that make you a "match"?

What's going to put us back to square one is if there's more than one person's DNA discovered on the letters. But the availability of improved DNA technology doesn't change the fact that there's no way around the scientific method. We simply need more samples.


By Douglas Oswell (Dowland) (237.philadelphia06rh.15.pa.dial-access.att.net - on Sunday, October 20, 2002 - 12:44 pm:

Ray, I think, even given the limited number of loci at hand, a partial match against a strong suspect would be something. And the ability to eliminate suspects would be invaluable, because it would help cut out some of the background noise.

By Kevin (Kevinrm) (ip68-98-108-6.ph.ph.cox.net - on Sunday, October 20, 2002 - 01:45 pm:

Did anyone else notice how they "blurred out" the actual numbers on the allels while they were showing it on TV? I kind of thought that was BS, especially when you consider they do not have enough at hand to make a "match" against anyone, only enough to rule out a suspect (since the DNA came from an authentic Z letter, it is my assertion that "for all practical purposes", it DOES rule out suspects). Had they not done that, I'm sure Doug would have been able to very quickly check them against TK.

By Douglas Oswell (Dowland) (236.philadelphia04rh.15.pa.dial-access.att.net - on Sunday, October 20, 2002 - 02:59 pm:

True, Kevin, as long as they're using the Polymarker and DQ-Alpha loci. In the "old days" of DNA analysis, those were the ones most frequently used. I'm not too sure what they're doing now, though.

By Ed N. (Ed_N) (pluto.cds1.net - on Sunday, October 20, 2002 - 10:15 pm:

Of course, other than TK and BD, I would certainly like to have all major suspects' DNA compared to Z's and either ruled in or eliminated. That includes O'Hare, Kane, Marshall and "Walker." To that small list, I'd also like to include Michael Roth (he's dead and buried (I don't believe he was cremated), so getting a sample should be easy), Jack Beeman (same as Roth), Robert Hunter (no, I do not for one second believe he's Z, but I would like to have his name cleared for the benefit of any hangers-on like Carl), Peter O. (if he can be found), Jim Phillips/Crabtree, and last, but certainly not least, none other than Gareth Penn himself (he cast much suspicion on himself from day one, and was actually a suspect in early 1981).

I would imagine that it would be quite difficult, if not impossible, to secure samples from most, if not all, of the above listed suspects. Even if samples were obtained, how long would it be without Primetime Live breathing down Dr. Hottttt's neck before she actually got around to testing them?

One thing not considered yet is that the presence of more than one type of DNA on the letters might indicate that some of what were thought to be authentic Z communiques are actually hoaxes that fooled Morrill. Now that would certainly throw a spanner in the works...

By Nick (Nick) ( on Monday, October 21, 2002 - 01:45 am:

I'm not going to hold my breath waiting for Davis, Kane, Marshall, Walker, Peter O, Phillips, Penn or anyone else to dive in and voluntarily provide a DNA sample. Hell, why would they. I would imagine the general response to be "why are you bothering me with this sh*t, I will sue you for harrassment". I personally wouldn't submit to any such request. I don't want my DNA profile in the gov's database. I've got nothing to hide, but for some reason, I just don't want it there. What's the point? It's going to take a court order or loved one's consent to have a body exhumed. I don't see that happening in this case. There are only so many folks out there who feel their stepdad is the zodiac killer.

By Classic (Classic) (cache-mtc-ak04.proxy.aol.com - on Monday, October 21, 2002 - 07:03 am:

Ed N., Yep I'd like to see all those people tested. Now what if a definitive z dna profile can be made, but none of those people match? Where does the case go from there? IMO, if that happens, the case is dead. There would be next zero chance of identifying z.

By Ray N (Ray_N) (sdn-ap-011scfairp0009.dialsprint.net - on Monday, October 21, 2002 - 09:41 am:


Yeah, I did notice that as I watched the show. It struck me that that was a legal issue for ABC, in that it provided identifying information for an individual who is not necessarily even a suspect in the case. Does the name "Richard Jewell" mean anything to anybody? In my view, despite the "conclusions" drawn by the show, this proves that ABC knows this might not be Zodiac DNA and they are covering their aft orifice. Maybe some other forensic analyst is sitting there going, "Hey, I'd recognize that sequence anywhere!" (Just kidding.)


I have learned that the panel used is called "Profiler Plus" that analyses the following 9 loci plus Amelogenin:

D3S1358, vWa, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820.

In one study, the most discriminating alleles were D18S51, FGA, and D21S11. Maybe someone with a tape of the show can determine if any of these were produced from the stamp sample.

Since the DNA flames seem to be dying down slightly on here, I'll take this opportunity to fan them a little. Check out the following links:

Dated April 2000:
Vermont v. Pfenning

Should We Trust Profiler Plus?

More information:
Sample cost sheet for DNA testing


By Ray N (Ray_N) (sdn-ap-011scfairp0009.dialsprint.net - on Monday, October 21, 2002 - 09:49 am:

Here is some more information related mainly to the Amelogenin Locus. Also, there is a pretty good reading list for at the bottom for anyone so inclined:


By Douglas Oswell (Dowland) (139.philadelphia04rh.16.pa.dial-access.att.net - on Monday, October 21, 2002 - 10:15 am:

Thanks for the info, Ray. I'm no expert on the subject, but I would imagine that, having used the PCR technique, they should have plenty of the Z specimen on hand to run the other tests, if they feel the need.

By Ray N (Ray_N) (sdn-ap-007scfairp0478.dialsprint.net - on Monday, October 21, 2002 - 04:31 pm:


I have been looking into the possibility of sample contamination with regard to SFPD's latest test. I wasn't completely sure how to respond to earlier challenges that since saliva was present on the stamp and the obvious DNA source target would have been epiphelial cells and not blood cells, this should not effect the outcome. My position was that maybe there was saliva on the stamp, but Z contaminated it by handling the shirt swatches when assembling, sealing, and putting postage on the relevant letters.

What I have found is that I was correct. The samples that are being tested are so small, it is possible that the analyst may not even be aware that there is a problem. This is particularly the case with PCR testing, since millions of copies of the sample are made. The copies that are made could easily be copies of the contamination. Here is the quote from the FBI information:

"Contamination: Because extremely small samples of DNA can be used as evidence, greater attention to contamination issues is necessary when identifying, collecting, and preserving DNA evidence. DNA evidence can be contaminated when DNA from another source gets mixed with DNA relevant to the case. This can happen when someone sneezes or coughs over the evidence or touches his/her mouth, nose, or other part of the face and then touches the area that may contain the DNA to be tested. Because a new DNA technology called "PCR" replicates or copies DNA in the evidence sample, the introduction of contaminants or other unintended DNA to an evidence sample can be problematic. With such minute samples of DNA being copied, extra care must be taken to prevent contamination. If a sample of DNA is submitted for testing, the PCR process will copy whatever DNA is present in the sample; it cannot distinguish between a suspect's DNA and DNA from another source." (emphasis mine)

Source page

So even though the police may have processed everything perfectly, the contamination may have already happened 33 years ago. Again, it is not presently my contention that this is what occurred. I only suggest that the situation dictates continued work before any hard conclusions are drawn.


By Jake (Jake) (cache-rp06.proxy.aol.com - on Monday, October 21, 2002 - 04:57 pm:

Roger that, Ray. The implication in the 10/15/02 Chronicle article is that the two additional 7/31/69 envelopes will be tested, too -- I think we're in agreement that all of the results should be checked against one another to ensure that we are, in fact, dealing with Zodiac DNA.


By Peter H (Peter_H) (pool-141-154-40-125.bos.east.verizon.net - on Tuesday, October 22, 2002 - 09:28 am:

Good catch, Ray. Bet the SFPD analyst never thought of any of this in her rush to exonerate ALA.

By Scott Bullock (Scott_Bullock) (cache-ntc-af07.proxy.aol.com - on Tuesday, October 22, 2002 - 03:05 pm:


She only "exonerated" Allen as the guy whose DNA she retrieved. Not one member of SFPD [that I recall, I didn't tape it] ever said, "Allen isn't the Zodiac."

As Ray has been elucidating extremely well, and as I have been saying since my first post on the subject, this particular sample means very little without corroboration from another sample. If the sample that SFPD possesses can be positively compared to another sample from a different letter, then we know that we have Zodiac's DNA and we can rule out Allen entirely. However, if a second sample doesn't match the first, then one of 2 things is likely: A) The sample was contaminated, or B) Zodiac was a team effort. Though I think the second scenario is unlikely, in either scenario Allen remains a suspect.

Anyway, I'm in 100% agreement with Ray and it is good to see that Jake is also. Before any conclusions can be made with regard to suspects, we have to be sure that the DNA SFPD found could belong to nobody other than the Zodiac.

For those of you who think that I'm looking for a way to hold on to Allen as a suspect, consider this: I think it's very probable that this initial sample will be corroborated by additional samples. Nevertheless, that would be the time to begin comparing results to other suspects; not now, when we can't say with 100% certainty that the sample belongs to the Zodiac. If another sample matches the first then Allen is out for sure, unless you buy into the "Allen did the killing and __________ did the writing" theory, which I don't.

By Jake (Jake) (cache-mtc-ak04.proxy.aol.com - on Tuesday, October 22, 2002 - 03:35 pm:

Scott wrote:
"Not one member of SFPD [that I recall, I didn't tape it] ever said, 'Allen isn't the Zodiac.'"

You recall correctly (the transcript is over at my site). No one has been explicitly ruled out based on this testing -- no one.

"However, if a second sample doesn't match the first, then one of 2 things is likely..."

What do we do if, upon testing two or more additional envelopes, we get more than two distinct DNA results?!? Paging Harry Martin...


By Peter H (Peter_H) (pool-141-154-19-196.bos.east.verizon.net - on Tuesday, October 22, 2002 - 04:00 pm:

I was pretty sure that three samples were tested: One from the Stine letter and two from the first Vallejo Times and Examiner letters, which had turned up in pristine condotion in someones persnal file. Anyone else recall this? I posted this on Friday and no one challenged it.

By Mark (Mark) (adsl-66-124-185-226.dsl.scrm01.pacbell.net - on Wednesday, October 23, 2002 - 07:33 am:

Hey, anybody hazard a guess on where the 3 additional "Missing" envelopes (did they have letters in them, can't remember if the show said so) materialized from?

By Peter H (Peter_H) (pool-141-154-19-196.bos.east.verizon.net - on Wednesday, October 23, 2002 - 08:06 am:

Ithink the narrator said someone's personal file, but didn't say who. Toschi maybe.

ANyone confirm my impression that these yielded samples as well?

By William Baker (Bill_Baker) (lsanca1-ar16-4-47-005-056.lsanca1.elnk.dsl.genuity.net - on Wednesday, October 23, 2002 - 10:38 am:

Peter, I haven't reviewed my tape of the program, so I can't be more specific, but a few days ago I posted a response to what you are saying about the DNA source coming from more than one envelope. It's my recollection that Dr. Holt said more than once, after the comparisons with ALA, et al, that it was from the stamp, singular. There were several envelopes displayed for the camera, all with sections cut out, which gave the viewer the mistaken impression that the testing material was the product of several sources. For whatever reason, only a stamp, that from a Stine letter as it is now revealed, provided the material for the partial DNA profile with which suspects were compared. This is why Ray and others have been calling for corroborative analyses from more than the one source, which would confirm or refute the validity of the DNA as consistent with that from other Z mailings, providing a clear and indisputable criterion for implicating/eliminating known suspects' DNA. I may be wrong, but that's what I recall.

By Peter H (Peter_H) (pool-141-154-18-176.bos.east.verizon.net - on Wednesday, October 23, 2002 - 11:01 am:

Could well be. Now that I think of it, that is probably what left me with the impression. I'll take the word of a trained investigator -- well certain ones -- any day.

By Lapumo (Lapumo) (p50-87.as1.clm.clonmel.eircom.net - on Monday, December 09, 2002 - 08:45 am:

Was there any mention of comparing the DNA from the stamp with that recovered from the CJB case?
Interesting that there was a hair sample recovered both times.Since Barnetts did not match....!

By Mcgarrett2000 (Mcgarrett2000) (sfmhinet.chw.edu - on Tuesday, December 10, 2002 - 01:27 pm:

Here is an article from the November 22, 2000 San Francisco Bay Guardian about SFPD's crime lab that this board may find interesting...

By Ed N. (Ed_N) (acc2f4f6.ipt.aol.com - on Tuesday, December 10, 2002 - 08:56 pm:

Really makes you think... no wonder SFPD ranks at the bottom for solving homicides.

By Esau (Esau) (12-246-187-137.client.attbi.com - on Wednesday, December 11, 2002 - 03:06 pm:

Of course SFPD fingerprint examiners aren't checked for accuracy. To check them in San Francisco they would first have to establish a board to hand pick the people who examine the examiners. Not as easy as it sounds in San Francisco. First, they would have to establish a numerical standard to qualify for the board. They would give preference points for women, minorities, illegal immigrants, handicapable and elderly. Then they would have to deduct points for males and veterans. They would have to deduct double the points for white males under 55 and veterans that actually experienced combat. Then they would have to try to pick a fingerprint examiner that wouldn't be offended by being checked.
That's pretty much how they pick their homicide squad. No wonder they can't solve a murder that hasn't been committed in front of a video camera or a police officer.

By Warren (Warren) (w205.z064002105.hou-tx.dsl.cnc.net - on Thursday, December 12, 2002 - 09:04 am:

Would SFPD deduct points for being heterosexual?

By Ray N (Ray_N) ( - on Sunday, December 29, 2002 - 03:23 pm:


Well, as the end of the year draws near, I find myself reflecting on the past 12 months with something of a sour feeling about the way the case now stands. Although I'm glad the DNA testing was done, I also have to come to grips with the fact that from the standpoint of law enforcement, the only way this case is going to be resolved is with DNA. Not that I'm saying I'm unhappy with the DNA because of the result, but because, in my mind, there is no real result - only the perception of a result in the minds of many....too many, actually. So with the budget concerns at SFPD and more tests apparently not forthcoming, I am somewhat saddened by the fact that the case has once again apparently stalled. Add to this the fact that I have spent a great deal of time helping Lapumo with his project, and you have a pretty disconcerted individual on your hands. Lapumo has essentially solved this case, but since so few people are familiar with the details of the work, and without definitive DNA results to back it up, the case once again languishes, and it does so needlessly, IMO. It is my sincere hope that continued effort will be expended in the coming year by law enforcement along all avenues that remain available to them.


By Ryan Olesin (Ryan) (d150-160-190.home.cgocable.net - on Sunday, December 29, 2002 - 03:33 pm:

Ray: I find myself reflecting on the past 12 months with something of a sour feeling about the way the case now stands

Well it could be worse. 12 months * 30+ years like other people.

Ray: Lapumo has essentially solved this case

Did I miss something? Feel free to start a new thread explaining this.

By Ray N (Ray_N) ( - on Sunday, December 29, 2002 - 04:28 pm:


I'm sorry if I gave the impression that I was taking it personally. I'm not. I only wanted to vent the frustration that I feel as a result of the current status of the case. I'm aware that others have invested more time dealing with this case than I have, most notably the families of the victims.

As far as the rest, Lapumo has posted on this already, but the details are not publicly available as of yet. Be that as it may, I will say it again - this case is solved. Law enforcement may or may not be able to eventually verify Zodiac's identity through DNA testing. I truly hope that they can.

I did not offer any of this in an antagonistic way, that is to say I'm not hoping to draw Allen opponents out for a fight. I'm just telling it like it is and talking about how I feel about the case at this juncture, should anyone care to put in their 2 cents worth along these lines.


By Ryan Olesin (Ryan) (d150-160-190.home.cgocable.net - on Sunday, December 29, 2002 - 05:34 pm:

What I meant was that getting sour about this case would not be the first time this happened to someone. I'm sure many other people have been up and down like mood swings. You're sour now, but something will probably happen again to make it not so sour.

By Valentine Smith (Valentinesmith) (cpe-gan-24-136-39-16-cmcpe.ncf.coxexpress.com - on Sunday, December 29, 2002 - 08:26 pm:

Well...I can't find if this has been asked already. But can you at least tell us if Lapumo's solution involves ANY of the major suspects listed on this site? Is it something that can't be discussed because of slander/libel type concerns?

Forgive my forwardness. I understand if nothing more can be revealed. I may not post much, but I DO try to keep current on the developments on the board...

By Nick (Nick) ( on Monday, December 30, 2002 - 02:06 am:

Sweet. The Ripper and Zodiac cases were both solved in the past year. It's a nice time to be alive.

By Tom Voigt (Tom_Voigt) (12-224-139-118.client.attbi.com - on Monday, December 30, 2002 - 02:11 am:

Nick, everyone knows the yellow book author solved the Zodiac case back in the 1980s and the Ripper case back in 1999 with The Bell Tower.
Get with the program!

By VSCANTU (Vscantu) (netcache-2002.public.lawson.webtv.net - on Monday, December 30, 2002 - 03:50 am:

RAY N: 'Thanks for sharing.' But WHERE has Lapumo posted how he has "solved this case."?! If you are being serious, you would probably let us all know what in Sam Hill you are talking about.

By Lapumo (Lapumo) (p51-9.as1.clm.clonmel.eircom.net - on Monday, December 30, 2002 - 06:12 am:

mmmm....How am I going to get out of this one?
I'll post on a new thread altogether, over in "theories" and explain as best I can.

By ParkGrubbs (Parkgrubbs) (cache-mtc-ak04.proxy.aol.com - on Friday, January 03, 2003 - 08:56 pm:

I just read this and the other thread on the subject all the way through and didn't catch which letter's stamp was tested. Which one was it?

By ParkGrubbs (Parkgrubbs) (cache-mtc-ak04.proxy.aol.com - on Friday, January 03, 2003 - 09:13 pm:

The reason why I'm asking is that, if it happened to be one of the questionable ones, such as the 78 letter, then the result is equally questionable.

By Gregusjay (Gregusjay) (12-234-233-242.client.attbi.com - on Saturday, January 25, 2003 - 06:43 pm:

Let's look at this again...SFPD has a partial DNA print from whom ever licked a Zodiac envelope. My understanding is that Dr. Hottie, also retrieved a partial print from the stamp as well..and it matched the print from the envelope.
So we should be able to safely assume that the same person licked the envelope and placed the stamp on this letter. With the new DNA procuring technology including PCR and others, my understanding is that the contamination risk is also diminished as they can gleen DNA at incredibly microscopic levels as well as procuring it without having to reduce down to such levels. As to what microscopic level did Dr. Hottie went down to to get the profile could be a determination in the contamination issue, as well as RNA contamination. I also understand that DNA chains or strands do not naturally change or attach to others. This way you can have multiple blood sampling mixed and still be able to tell how many different peoples blood are evident. The one way this can be thrown off is if identical twins are involved since they carry identical DNA structure. In sum, I'd have to say that the DNA in the SF lab is the key and that it's a clean key.

By Kevin (Kevinrm) (ip68-98-108-6.ph.ph.cox.net - on Sunday, January 26, 2003 - 12:15 am:

Greg, I totally agree. However, it doesn't fit in with some people's pet suspect, so there obviously must be some sort of problem with the DNA somewhere, right?

By Tom Voigt (Tom_Voigt) (12-224-139-118.client.attbi.com - on Sunday, January 26, 2003 - 12:47 am:

Greg and Kevin, my feeling is the Zodiac could still be Allen, Kaczynski, Davis, Kane, Marshall or anyone else who has been (or will be) compared to the DNA fingerprint recovered from the stamp and letter.

Simply put, the possibility exists Zodiac didn't lick his own stamps and envelopes. However, if SFPD finds the same DNA fingerprint on additional stamps and envelopes, IMHO the likelihood decreases drastically.

By Linda (Linda) (208-59-124-98.s98.tnt1.frdr.md.dialup.rcn.com - on Sunday, January 26, 2003 - 02:11 am:

Zodiac enjoyed needling, teasing and making fun of those trying to capture him. He took pride in announcing, through his correspondences, that he was too clever for the police and that he left no fingerprints behind at the Stine murder because he was wearing fingerprint guards consisting of two coats of airplane cement. I think if Z had any concern about future identification being done through testing of bodily fluids such as saliva through the licking of stamps, envelopes, he would probably have chided so in other correspondences. (I can almost imagine him snickering to himself as he wrote of his shrewdness).

I really think that Z licked his own stamps/envelopes. We know that the Unabomber, too, was clever, and took many precautions to fool the police; however, even he licked his own stamps/envelopes. We know this because DNA was retrieved from some to identify him...

This leads me to believe that if Ted was the Zodiac and the S.F. Police Dept ever divulge the comparisons between the Z samples retrieved and TK, there is sure to be a match...if not, I would have to believe Ted was NOT the Zodiac...

By Gregusjay (Gregusjay) (12-234-233-242.client.attbi.com - on Sunday, January 26, 2003 - 12:45 pm:

One of the things I am sure we are all interested in, is what SFPD is doing to close the case? We saw Dr. Holt receive more letters and envelopes, and it sort of left this show as a cliff-hanger. Coupled with the advent of Tom's "I'm still here" letters, one hopes that we are very, very close to discovering who Z really was/is. My field of suspects is still open as well, until we can definately get an admission or conclusive evidence. It's a shame that this case has lingered for 30 odd years.
Thank God it's still in the public eye.

By Muskogee (Muskogee) (216-19-219-89.getnet.net - on Sunday, January 26, 2003 - 12:55 pm:

It's still very possible there is contamination because, to my knowledge, no one was LOOKING for DNA from more than one person during the televised analysis.

DNA analysis is much more complicated than Gregusjay's post indicates. DNA is not evaluated intact (so you can't say, "Hmmm, there are 5 different types of DNA here, indicating that 5 different people handled this letter."). DNA is cleaved at multiple sites and the locations of the cleavage determines the sizes the DNA breaks into. You can then measure those pieces against those of a known suspect. If there are "extra" fragments, they may be disregarded if you have a match to the suspect. However, all bets are off if you don't have a match.

I believe it is difficult to tell how many other sources of DNA you have, unless you also have people who's DNA "fingerprints" match. I believe one should be able to at least know there is more than one DNA profile involved, though.

This is my understanding (I haven't done this stuff in 4 years, so anyone more current on the subject, feel free to correct any errors). Also, I've never worked with "old" DNA that may have deteriorated significantly. I would think this would only strengthen what I've stated previously, but, again, I don't know from personal experience.

By Ray N (Ray_N) ( - on Sunday, January 26, 2003 - 02:20 pm:


Your information is incorrect. Partial results do not "match" each other. No "safe assumptions" can be made. Only plain old fashioned assumptions. There are not any profiles available which can be compared to each other. PCR testing is most vulnerable to contamination particularly when, as in this case, the technology is brought to bear on old, tiny samples which is in fact what we have. PCR was not developed as a tool for this kind of work, it is instead being pressed into service in a role for which there are pitfalls.

Too many people it seems are playing fast and loose with the "common sense" approach to what DNA is/is not capable of what what the results do/do not mean. This is of course understandable given the complex nature of the technology, but I would think that would serve to put posters to the task of educating themselves a bit before reaching conclusions and making safe assumptions. For example, and this was illustrated during the Primetime segment, Dr. Holt wasn't "going in there" and looking around for a particular strand to test, like she would see a friendly stand waving to her if only she'd put her microscope on high power. In fact, she relied totally on the computerized equipment to tell her if there was even any DNA there at all. The test was performed on what was present, and there is no way to tell, outside of additional tests, if that sample was donated by Zodiac. Personally, my opinion is that with the information we have available now, it is just as likely Paul Stine's DNA as Zodiac's. Before someone else asks if I mean did Zodiac put the stamp on Stine's tongue, think a bit about what we know about Z's actions in putting these mailings together. Hmm, that might even give us a better directed domain for further tests, might it not?

I have put some links on a previous post related to PCR, what it is, what the potential problems are with it, and why the evidence in this case is directly on point with this information. Or, better yet, find your own links. The point is, without a match, which we don't have, there's no way to tell if contaimination occurred. Well, apart from, you guessed it, a second test that produces different results from the first.

Regardless, this type of position always sparks the same conversation, whose inevitable end is the conclusion that more testing is required. There is simply no getting around this, and I don't see the point, let me rephrase that, there is no point in drawing conclusions and making assumptions, "safe" or otherwise, until such testing is accomplished. This is not to say that folks who think SFPD has a partial Z DNA profile are going to be proven wrong. If complete, matching profiles can be developed from different areas, I will gladly accept the results of any comparison done with them, to include the elimination of Allen as a Zodiac suspect. But again, strong independent evidence exists that indicates this will not happen.

But I stand ready to be corrected as soon as usable results are in.


By Muskogee (Muskogee) (216-19-219-89.getnet.net - on Sunday, January 26, 2003 - 03:48 pm:

Thanks, Ray! Very articulate.

By Gregusjay (Gregusjay) (12-234-233-242.client.attbi.com - on Sunday, January 26, 2003 - 08:56 pm:

I believe SFPD admitted that on some of the envelopes the DNA was not usable, or was "faint" but that there was a partial (4 out of nine markers plus a gender indicator) print gleened from one (the Nov. 8 1969 card) that was good enough to eliminate suspects, but not good enough to ID a suspect.
My intent in my previous post was to clarify and re-cap where the DNA testing has left us, and to see where it's going. I understand that there were still 3 new envelopes to hopefully get stronger results and enough DNA to finally ID a suspect.

By Gregusjay (Gregusjay) (12-234-233-242.client.attbi.com - on Sunday, January 26, 2003 - 10:16 pm:

In addendum to my post of 8:65, and to Ray's post, I know that even though SFPD may get a full DNA profile from the envelopes, etc. We would still need to have suspects to check it against to get a 100% postive ID...that's a given, but SFPD says they have enough of a DNA print to exclude suspects.
Also, the partial print came from the dripping pen card envelope, which was mailed before the Stine murder, so there shouldn't be any contamination committed by Z anyway.

By Douglas Oswell (Dowland) (80.philadelphia01rh.15.pa.dial-access.att.net - on Monday, January 27, 2003 - 03:19 am:

Actually, the Dripping Pen card was mailed about a month after the Stine murder.

By Gregusjay (Gregusjay) (206-169-111-251.ihe.com - on Monday, January 27, 2003 - 09:31 am:

Oops thanks Doug, I was looking at another website and transposed the dates. So my bad..as they say..sorry..
But I still stand by the fact that there are enough DNA markers to eliminate suspects...
of course we still don't know who licked the envelopes and stamps, but one who have to rely that the writer did or in the least knows who wrote the letters. I am sure Holt's taken into account that there could be blood taint from Stine..and they have the rest of his shirt to compare it against.

By Carolyn (Carolyn) (dialup- - on Monday, January 27, 2003 - 06:19 pm:

Perhaps one of the real fascinations of checking out TK would be that if he is the real Z, then we would have an actual live entity to question about it (hopefully) as opposed to a dead person who cannot answer back to our questions.

By Ray N (Ray_N) ( - on Tuesday, January 28, 2003 - 12:47 pm:


You wrote, "I am sure Holt's taken into account that there could be blood taint from Stine..and they have the rest of his shirt to compare it against."

I'm not. In fact, I know she hasn't, because (a) PCR results don't tell you if they are the result of a contaminated sample. That's one of the pitfalls of PCR. The only way to figure it out is by doing more tests, either on the letters or on Stine's shirt as you point out. Only problem with this is that (b) this test hasn't been done. Hmmm. I don't suppose any Zodiac DNA is on the shirt?

You also wrote, "SFPD says they have enough of a DNA print to exclude suspects."

Actually, they have said no such thing. And if they do say it, they will be wrong. What they have said is that they can eliminate individuals as the source of the DNA on the stamp. I believe you are referring to recent statements made to the media and perhaps the ABC segment. Be careful about reading meaning into what has actually been said. Dr. Holt said the same thing: "This test eliminates Arthur Leigh Allen as the person who contributed this DNA." She knows that it cannot be determined if the source of that DNA was the Zodiac (yes, it might be but it also might not be), so no determination can be made about Allen being Zodiac from that test. Otherwise, she could have made a far more definitive statement. ABC apparently did not feel it needed to be as careful or accurate about the statements it made. They decided they needed a more definitive result. John Quiniones told a man flat out that his father was not Zodiac based on tests paid for by ABC. This is a glaring example of reckless and irresponsible "journalism". Well, maybe journalism isn't the right term. Instead of reporting the facts, a serious effort was made to get people excited. After all, a show without an exciting conclusion isn't much of a show. Really what they had was a show without any conclusion which they had to make look like something it wasn't to boost the entertainment value.

Here is the proper logic to follow when determining that the test has meaning with regard to any one partucular person:

We know that if A=B and B=C, then A=C.

To begin:
Let A represent the DNA profile of Zodiac.
Let B represent the DNA profile of the DNA from the stamp.
Let C represent the DNA profile of a RANDOM individual whose role as the author is being probed.

To eliminate the individual as the author, we obviously must show the condition A not= C. But in order to accurately make this elimination we must also show the condition A=B, or we have proven nothing. In plain language, we have to prove that Zodiac's DNA is the DNA that showed up on the stamp. (A=B) The only way to do this is to find multiple appearances of the same DNA on different letters known to have originated from Zodiac. The good news is that it is "probably reasonable" to accomplish this even with a partial DNA profile. In other words, if we got half a dozen samples from different letters and there were no inconsistencies that could be identified between any of the samples, we might be able to conclude that all of the samples are from the same source. This would not be 100% kosher from a pure scientific standpoint. That would require all profiles to be complete, but we ain't gonna get there with what we've got to work with, so we have to get smart and creative, but with caution. Since we have only one sample, we cannot know the value of the A-B relationship. Of course, the issue with this is the possibility of contamination. If we had more tests done, and got more than one profile, we could both prove contamination, but also may be able to isolate Zodiac DNA from the contamination or disprove contamination altogether.

Some, including ABC, have embraced elimination by means of simply assuming beforehand that A=B and then showing B not= C. This might make good television but it doesn't pass scientific muster.

In order to prove someone the author, we must show both A=B and B=C, both requiring complete profiles for the comparisons. Obviously this is much harder to do, and it is likely that we will never be able to do it directly.

Going back to what I said earlier about being carefully creative, what we might be able to do with a broader range of tests would be to rule out contamination and at the same time construct a more complete Zodiac profile. I realize that this departs from the truest course of rectitude, and that it would be vehemently attacked in court, possibly even on this board, but it goes like this. Let's say we lay out a simplified Profiler Plus grid for purposes of explanation:


Now let's lay in a sample partial result, to represent what we have now from the stamp test:

Partial Stamp Profile (Poss. Zodiac DNA):

Yes, I know this isn't really what the results look like, I am simplifying for clarity but the logic remains intact. Now, let's create some other fictitious results from tests that we assume are going to take place in the future but are only going to yield partial results:

Test 2

We can see that this result also indicates a male donor, as well as the fact that there are overlaps at 2 and 7. Therefore, this result is not inconsistent with the first, in other words, it could have come from the same person who donated the first sample. Obviously, the more overlaps there are the better. And the best way to ensure more overlaps and at the same time disprove contamination, is to have a large number of partial profiles all taken from different areas on the mailings. I am showing a gender on each test because the gender is not actually determined at the same time and in the same way as the rest of the result. It is a different procedure, but is appended on at the end. I'm pretty sure this it should almost always be available. But if not, it's still OK as long as it is never (F)emale.

Continuing on with this craziness,

Test 3

Again, we have overlaps without inconsistencies, and we also have developed the following composite profile:


Now that's quite an improvement. There's no way to prove that this represents an actual person or not, but there's no way to disprove it either. And so, if we were to find a partial match to the profile of an actual person with 9 out of 10 that would be interesting. It would be quite significant if that person also happened to be a leading Zodiac suspect, would it not?

The last question brings up the point about whether the author and Zodiac were in fact the same person. After all, we can only prove that a person calling himself Zodiac wrote the letters. It may be a small leap to convicting the author of doing the killings, but it is a leap nonetheless. To solve this remaining problem, one would have to have the identity of the anonymous donor revealed. If it turned out to be a 9-year old boy from Minneapolis, we would have to conclude that more than one person share the same gene pattern at the test locations, which is entirely possible. But, on the other hand, if that person turned out to be someone who lived in the area at the time of the crimes, fit the profile, etc. We would have a strong new suspect. Finally, if the person turned out to be someone who was already a leading suspect, we'd have to conclude that the odds of a 9/10ths match of that person's DNA appearing at random under the stamp of a confirmed Zodiac letter would have to be no less than that of the same match for a 9-year old boy from Minneapolis multiplied by a number at least as large as the number of people living in the Bay Area in 1969. And that would make it just about impossible for that person to not be Zodiac.

Now is this a pure method without flaws? No. Would it work? I don't know. Is it worth a try? I don't know. Would it convince me of someone's guilt or innocence? I don't know. I do know that the more overlapping samples without inconsistencies there were, the greater the odds we were dealing with the DNA of one person would be. And this number would increase exponentially with the number of profiles composited. I also know that doing nothing will always result in failure.

BTW, did I mention the need for more tests?


By Gregusjay (Gregusjay) (12-234-233-242.client.attbi.com - on Tuesday, January 28, 2003 - 07:34 pm:

ok, Ray, so in a nutshell...without knowing who Z really is, we won't know who's DNA we could have..so for right now the DNA is somebody whom we have to assume licked the envelope and one of the stamps, but may or may not have been the killer, or the writer, because all we know now is that there is some DNA on a licked envelope. I'll buy that...
And so going forward Allen could still be Z as the killer and not the writer or the licker...and because of the odds involved in the
profile of DNA...so the way it should be put at SFPD is....
"the DNA from the envelope does not match Arthur Leigh Allen's DNA profile, but since we don't know Z's modus operandi, we can not conclude who Z is, nor count out Arthut Leigh Allen as Z, and even if there is full profile eventually gleened from the remaining envelopes, it is only the profile of the licker, not the killer.
Am I close now? whew....
By the way did Allen have a licker license??
(I had to throw that in there..) brrrmmm tssshhh

By Howard Davis (Howard) ( - on Wednesday, January 29, 2003 - 06:45 pm:

Dr.Hot has been contacted and she affirmed once again,that she definitely thinks that her testing has ruled out the three suspects that were tested.This is her professional opinion,but of course,it will remain open for debate.She feels there is no room for debate.
The detectives do not want anyone contacting her,but I say they are public servants payed by the taxpayers and the public has a right to know as much as possible about these kinds of opinions.

By Gregusjay (Gregusjay) (12-234-233-242.client.attbi.com - on Wednesday, January 29, 2003 - 08:02 pm:

Thanks for the input Howard...
I am still hoping they can pull a full DNA profile..could you imagine cloning Zodiac?...if anything, to see what he may have looked like.
Or in the least, a clone of the envelope licker.

By Douglas Oswell (Dowland) (182.philadelphia01rh.16.pa.dial-access.att.net - on Thursday, January 30, 2003 - 09:56 am:

Gregusjay, a clone of Zodiac would be formed as an infant human being with all the rights and amenities pertaining thereto--not an an inanimate object for us Zodiac researchers to gawk and gape over. But of course, you know that!

By Ray N (Ray_N) ( - on Thursday, January 30, 2003 - 03:57 pm:

The DNA cannot be assumed to be from the individual who licked the stamp. There are some very strange things about these letters. I have learned that at least one of the envelope flaps was tested and was found not to contain amylase. So we have an unlicked flap and a licked stamp. Weird. All that can be said about the DNA is that it is human DNA from an unknown source. If we get matching results from other letters, hard to do with an incomplete profile, but maybe it will happen, we can say then say that it is from the stamp licker, and we can also say that the stamp licker is the Zodiac.

Again, even though Dr. Holt is making the same statement again, it is important to understand what her statement is. Howard, if she said the same thing to you she said on Primetime, then she must have said that Allen et. al. did not contribute the material analysed. That much is beyond debate, I will agree. This does not mean they were not the Zodiac, or they didn't lick the stamp. Notice how she didn't say "Allen isn't Zodiac." She said, "Allen didn't contribute the material." Surely there is no one here who cannot follow the potential transfer of blood from the bloody shirt swatch to the fingers of Zodiac (gloved or not) to the stamp, envelope, etc. And that's just one possible avenue offered as an example.

That's the great thing about being an expert, particularly in the field of DNA. One often does not have to give a full account of why their opinion is what it is, particularly to the public at large. But as with many things, the devil is in the details, and one has to ask for these details to be fully satisfied. For example, my question is, "Dr. Holt, why is it impossible for the tested sample to be contaminated with the DNA of another person?" In other words, prove to me that the sample was not contaminated and I'll defer. Don't just tell me it wasn't, tell me exactly why it wasn't, and don't worry about confusing me. If I don't understand something, I can read and learn. I reject the "this equipment is so good and the methodology so sound" argument in the face of law enforcement training documents easily found online which all advocate taking great care to avoid contaminating the samples being collected with sweat, tears, saliva, mucous, etc. If the methodology is foolproof, then why is contamination such a concern?

Here's what we're looking at. In forensics, normally what they do is do a test on something that is known. In other words, they have a spot of blood at a crime scene. So whoever left it was there. Easy enough. But there's a lot of blood in a drop of blood, and a drop of blood is what it is - blood laying on the floor. Not too much detective work involved in figuring that out. Or we have a rape kit, where semen is being tested. Well, we don't have to do much detective work to decide that the semen is from the rapist either. Now we have the incomparable case of the Zodiac in which we have a tiny, 33 year old sample of DNA behind a stamp, which was licked but we don't know by whom, and that person just got done stuffing a probably still damp piece of bloody cloth in there just before he tore off a stamp and put it on. And, we have a piece of evidence that has had 33 years to get poked prodded, passed around, handled, inspected, lost, found, whatever, you get the idea. But I'm supposed to just say, oh don't worry, the methodology is sound. If there's a reason it's not contaminated, fine, tell me what it is. Before I accept anything, they're going to have to prove to me what it was that they tested. And my position is that they don't know, because at the present time they have no way of knowing.


By Gregusjay (Gregusjay) (12-234-233-242.client.attbi.com - on Thursday, January 30, 2003 - 06:47 pm:

Ray, I like the way you are not too easily swayed. Police forensics are perpetually changing, fortunately, for the police, science tends to be on their side. My brother in law is a detective and my sister a crime-scene photographer for a large bay area city. It's natural for us as citizens to question how much faith police departments put into these sciences
(especially defense attorneys, but that's another thread). With what little I know about DNA, my understanding is that with PCR profiling they can re-create a large part of the DNA structure from a very, very, very much smaller part of that DNA strand or partial strand. I also understand that when DNA profilers talk of contamination, it's generally, contamination from RNA. I also understand that the PCR process has changed immensely from even the days of OJ's trial. A big and very harsh lesson was learned by most police forensic departments after that trial.
So, in as much as questions existing about DNA procurement and profiling, one has to rely on the fact that it's evolving towards the positive and not towards negative or unsure results.

By Douglas Oswell (Dowland) (2.philadelphia08rh.16.pa.dial-access.att.net - on Friday, January 31, 2003 - 03:33 am:

The trouble arises when police agencies use DNA as an exclusionary, rather than an inclusionary tool. A positive DNA match to an otherwise good suspect is highly damning, whereas a "negative" match simply indicates that the subject didn't contribute the specimen--not that he wasn't at the crime scene or didn't participate in the crime. Exclusionary use relies much more heavily upon probabilities.

By ZK (Zk) (ip-24-197-136-036.spart.sc.charter.com - on Friday, January 31, 2003 - 03:06 pm:

The method involved here: is that a DNA-fingerprint was recovered from a saliva sample from a sealed stamp. The other options just aren't reasonable options....Zerlock.

By Howard Davis (Howard) (host-66-81-28-178.rev.o1.com - on Monday, February 17, 2003 - 12:36 am:

Or, if it ain't his spit you must acquit!JJ

By Ryan Olesin (Ryan) (d150-160-190.home.cgocable.net - on Thursday, June 19, 2003 - 12:43 pm:

Do the colours on the DNA profile mean anything?

By Howard Davis (Howard) (host-66-81-29-223.rev.o1.com - on Friday, June 20, 2003 - 12:49 am:

Just click Google then type "dna colors."
One site is :How do we Sequence DNA?Then towards the end of the narrative you find:
An Automated Sequencing gel and A Scan of one gel lane.
But,there is more to it ,so one has to just keep reading on and on...