In 2002, ABC News in conjunction with SFPD developed a small fragment of DNA from one of the Zodiac letters.  The fragment is comprised of four alleles, or genetic markers, out of the nine they were testing for.  As part of that show, Mr. X volunteered a sample of his own DNA for comparison.  When the samples were compared, it was found that the DNA obtained from the Zodiac letter did not match that of Mr. X.  Although SFPD did not state it overtly on the show, this match effectively seemed to rule out Mr. X (as well as Art Allen and one other individual) as a suspect in the Zodiac case in the eyes of anyone who viewed the show.  Some people have argued that the issue of whether or not the DNA from the letter that SFPD analyzed actually belongs to the killer is irrelevant:  The mere fact that Mr. X volunteered his DNA against an unknown quantity is proof positive that he is innocent of involvement in the Zodiac crimes.

I feel that based on my own knowledge of the case, what I’ve learned about DNA analysis since 2002 and based on Mr. X’s background and (as was discussed in the previous section) the fact that he was present on the streets shortly after the Stine murder, it is time to revisit these conclusions.

Over the past fifteen years or so, DNA has emerged as the great final arbiter in criminal cases.  DNA exclusions can, after all, range into the “one in six billion” realm, which is the same as virtual statistical certainty.  This type of statistical odds can easily overwhelm the average person and blind them to any shortcomings of the procedure.  The technology has solved decades old crimes and has set people free who had been wrongly convicted by conventional evidence.  However, in the case of the Zodiac killer, where much of the evidence in the case is subjective and debatable and where nothing may be what it seems on the surface, even the DNA is something that has to be looked at with a jaded eye.  To quote an old saying that pertains to the computer field, the Zodiac DNA may be a case of “garbage in/garbage out.”  As with everything in life, no lab test, not even DNA, is infallible: The value of a DNA analysis is directly proportional to the quality of the DNA we are working with to begin with.  And the quality of the DNA is, in turn, a function of how the letter from which it was obtained was handled from 1969 until 2002.  There are several issues that need to be examined, some of them related to the Zodiac letters, some to lab practices and the other is specific to Mr. X himself.

THE ZODIAC LETTERS

The Zodiac letters first began arriving at the offices of the local Northern California newspapers in July 1969, many years before the advent of DNA analysis. DNA evidence can be very easily contaminated, as anyone who watches even TV shows like CSI will know.  The problem that this creates is that in order to process any type of evidence for DNA, that evidence must first be meticulously protected from outside contamination. 

The reason DNA evidence is so easily contaminated is that there are many potential sources of DNA in our environment.  These contaminants include saliva, which can be inadvertently applied to a letter by sneezing on it, coughing while looking at it, speaking while holding it and even licking your finger before touching a letter that is to be analyzed for DNA.  This is why the collection of DNA evidence is subject to very stringent protocols, such as the crime scene technician being forced to change his or her gloves after collecting each sample, in order to prevent cross-contamination, as well as the need to bag individual samples in order to protect them from the outside environment prior to lab analysis.  Ironically, one of the biggest dangers in DNA forensic work is that the evidence can be contaminated by the person who is actually collecting it or who is going to perform the laboratory analysis of the sample!

Now let’s look at the Zodiac letters.  First, as stated above, these letters arrived at a time when there was no inkling whatsoever of the coming of DNA testing, the theory of which would not be forthcoming until many years in the future.  These letters were tested at the time they arrived for fingerprints by the use of Ninhydrin.  However, after they were analyzed for prints (and possibly impressed writing), since there were no other chemical or physical lab tests that were performed in those days, there were no stringent requirements for protecting these letters from the outside world.  Even though these letters were kept in protective covers during the times when they were in police custody, I am certain that there was no policy that prevented a handwriting analyst from removing the letters and envelopes for closer analysis outside of the plastic sleeve they may have been in.  In addition, a producer from ABC told me confidentially shortly after the ABC show aired in 2002 that all of the Zodiac letters, which would include the one from which the DNA was obtained by SFPD in 2002, were out of the chain of custody at one time or another.  (The phrase “outside the chain of custody” is just a euphemism for the fact that these letters had been taken home as “trophies” by various detectives or lab personnel and kept in their “private files”, which could be a desk or a garage.  And of course, since these letters were considered trophies, they were probably handed around and shown off to friends, family and celebrities that may have passed through SFPD at various times, etc.  In fact, three Zodiac letters that had been in someone’s “private files” suddenly reappeared at SFPD after ABC arrived in their lab and DNA testing was supposed to be done on the letters.)

Therefore, the potential for the Zodiac letters to have been subject to contamination by exogenous DNA due to indiscriminate handling since 1969 is extremely high.  In fact, each one of them should be considered to be highly contaminated by exogenous DNA until proven otherwise.  There are ways to overcome this problem by the way the letters are analyzed, so let’s look at that next issue.

THE EXTRACTION TECHNIQUE

One of the first steps in DNA analysis is getting the DNA off of (in this case) the letter or envelope and into solution in a test tube.  This is called “extracting” the DNA from the sample.  Recently on www.zodiackiller.com, one such technique was presented in the form of a published paper from a scientific journal.  Here is a link to this article, with thanks to Ray Nixon and the zodiackiller.com Message Board, where the link was posted. (Note: The link that I had included here to this article on the FBI website, www.fbi.gov,  is no longer active.) 
 

This paper is written by laboratory personnel and clearly does not take into account the “real world” problems that the lab personnel analyzing the Zodiac letters encountered.  As a matter of fact, this methodology represents be the last extraction technique one would want to use to obtain DNA from an envelope like the one SFPD used to get its sample!  Here is a quote from the article:

“DNA was extracted from nine stamps using a Qiagen QIAamp DNA Mini Kit and a Genomic DNA Isolation Kit for Tissue and Cells supplied by nexttec. Postage stamps (55 cents, Germany, bird series, 2004) always licked once by the same person were used as starting material for all experiments. The stamps were stuck to a white paper (80 g/m²) and stored approximately 24 hours at room temperature. No attempt was made to separate the stamps from the paper. Nine 20- by 5-mm sample areas of the stamps were cut into small pieces. The DNA was extracted in three different ways.  Six samples involved incubation in 80 µL of nexttec lysis buffer, and three samples involved incubation in 180 µL of QIAamp buffer ATL with 20 µL of proteinase K (20 mg/mL) of the silica-based system. All samples were incubated overnight at 56 °C.  ” (italics mine)

A stamp obviously has two surfaces, an “outside” surface and an “inside” surface.  The “outside” surface is the one that has been exposed to the environment since 1969 and which could have exogenous (or “contaminant”) DNA on it that does not come from the person who licked the stamp in 1969.  The “inside” of the stamp is the “glue side” and would contain any DNA that may have been left by saliva from the person who actually applied the stamp to the letter.  This side of the stamp has been protected from the outside world since 1969 (in the case of the particular Zodiac letter used by SFPD for its analysis in 2002) and is not likely to have been subjected to exposure to “contaminant” DNA.

In the article cited above, the method of extraction consists of cutting off a piece of the paper/stamp and placing the entire piece in an extracting solution.  Assuming that SFPD used an analogous procedure to extract DNA from its envelope flap in 2002 (which we have to do conservatively at this point, since it is apparently a common lab procedure and because we lack insight as to how SFPD did the extraction), then it was extracting DNA from not only the “inside” surface of the flap but also from the “outside” surface of the flap, where the contaminant DNA is located.  Due to the high probability that the Zodiac letters, as discussed above, were likely to have been contaminated with exogenous DNA, the DNA that SFPD currently has in its possession may well be of highly questionable probative value.  DNA that is obtained from the envelopes in this manner, therefore, must be used cautiously.

The other part of the contamination equation is the specialized laboratory technique that SFPD also used on the Zodiac letters: “polymerase chain reaction” or “PCR,” for short.  This technique was developed in order to make it possible for scientists to analyze minute pieces of DNA that are so small as to fall below the level of detection for their lab equipment.  PCR has the advantage (and the caveat, in the case of the Zodiac letters) of taking the most minute fragment of DNA and multiplying it millions upon millions of times, so that it is present in sufficient enough quantity to rise to a level that is detectable by the machine that reads the DNA samples.  There is a danger in using the PCR technique in potentially contaminated samples, since the technique cannot discriminate between the DNA you are looking for from a suspect and the contaminant DNA.  The problem is that the PCR technique magnifies any DNA that it is “fed” by the lab technicians. 

Therefore, by using the PCR technique in conjunction with potentially contaminated envelopes that are extracted in a solution that takes DNA from both the inside and the outside of the piece of envelope, you are creating a situation that almost represents an “abuse” of the PCR technique.  You are potentially allowing PCR to amplify DNA that is not necessarily from the suspect in question.  PCR did in fact magnify a fragment of DNA from one of the Zodiac letters.  But whose DNA was it?  Since this was not a controlled lab experiment which used a known source of DNA, nobody can be sure at this point whose DNA SFPD has.

A CAVEAT

At this point, I am not asserting that SFPD definitely does not have Zodiac’s DNA in its possession.  However, I feel that since there are serious questions as to how they obtained their sample, it cannot be concluded by the general public that they have Zodiac’s DNA in their possession until some answers are forthcoming on SFPD’s “Materials and Methods.”  There are things that SFPD could have done to insure that they obtained the DNA they were looking for.

So how does a lab overcome this shortcoming of the DNA process and try to learn if the DNA it has is signal or noise?  There is are two very simple methods for this:  1) The lab can analyze multiple letters from the same series and see if the DNA is consistent across at least two of them and/or 2) The lab can use an extraction technique that  selectively extracts the DNA from just one side of the piece of envelope.  An example of such a technique would be steaming the glue side only of the envelope flap to remove the DNA from just one side of the flap.

Since SFPD does not deem it appropriate to share even its “Materials and Methods” with the public, we have no idea if it took both or either of these steps.  It is widely believed that the current DNA comes from only one Zodiac letter, so apparently (unless the 1978 letter from which SFPD obtained DNA in the 1990s was proven to be authentic or DNA obtained from this letter matched the DNA on the 1969 letter) their sample was not cross-referenced across at least two of the existing letters.  As for what technique the lab used to extract the DNA, a “one-sided extraction” or “two-sided extraction,” only SFPD knows that for certain.

On the ABC show, SFPD never made it clear just how the DNA sample it obtained was being used as evidence.  Samples can be used for either “inclusion” or “exclusion.”  A sample of DNA that definitely comes from a perpetrator can be used for excluding (or eliminating) suspects that do not match it. (In other words, if a given suspect does not match the DNA, it proves conclusively that he is not guilty of the crimes.)   Such would be the case in the series of crimes committed by the killer known as “BTK” in Wichita, KS.  The DNA that the police had in their possession since 1974 came from semen that was left at the scene of one of the attacks.  Therefore, the police knew that when and if they could find a match to that DNA, they would have found someone who had definitely been at that crime scene. 

Given the possibility that the SFPD DNA may be a contaminant, my own feeling (which is shared by other people) is that it should only be used for inclusion, meaning that if it matches someone, that person has to be looked at very carefully.  However, if it does not match a sample obtained either voluntarily or involuntarily from a person of interest, that should not necessarily rule that individual out from further scrutiny, especially when that suspect has a strong circumstantial case surrounding him and was also accosted by an SFPD officer shortly after the attack on Paul Stine on October 11, 1969.

A CONVERSATION FROM 2002

Shortly after the ABC show aired, a fellow Zodiac researcher and retired CHiP officer named Lyndon Lafferty contacted SFPD and spoke to the late Insp. Mike Maloney about the DNA in the Zodiac case.  At that time, Insp. Maloney indicated to Mr. Lafferty that SFPD considered the DNA they had to be “premature” in nature.  When a startled Mr. Lafferty followed up that comment by asking Maloney if that meant that the DNA was “invalid,” Maloney paused for a moment to consider his response and then said that the DNA was in fact “invalid.”

How can SFPD be excluding suspects or even allowing a television show to tape comparisons in its lab between the DNA from various individuals and its DNA sample if it feels that the DNA it has in its possession is “invalid?” If such is the case, why was no further testing apparently ever done to determine its probative value by matching it to DNA from another letter?  This conversation seems to prove that the DNA in its current state can only by used in a conservative manner, or to include a suspect.

MR. X AND SALIVA TESTING

There is another layer of mystery when it comes to Mr. X and DNA.  He clearly volunteered a sample of his DNA to ABC for comparison to the DNA obtained from the Zodiac evidence.  This could obviously mean that he has nothing to hide, as some people have strongly asserted.  However, there is another possibility of which I know from my years of research into his past, research of which the general public is simply not aware.

(Nor, to my knowledge, was ABC aware of it in 2002, since I learned this fact after their show aired.)

Mr. X has a hobby that would have almost inevitably have exposed him to the concept of saliva testing for something, testing that had been going on for years before he became interested in the hobby.  Although he denied knowing about this type of testing in my September 2006 interview with him, I have since contacted several experts in this field and they all confirmed what I had learned several years ago.  Namely, that someone who has been at this hobby for as long as Mr. X has would almost certainly be aware of saliva testing for something. (Note: I am not at liberty to discuss what this hobby is, the nature of the testing or what kind of experts I spoke to because it might tend to identify Mr. X.)

Therefore, in 1969 Mr. X would most likely have been generally aware that saliva testing was used for something that could be used to identify someone in some manner (not DNA but some other parameter).  He may therefore have taken steps to avoid licking his own stamps.  An identical scenario has been proposed for Arthur Leigh Allen.  Shortly after the 2002 ABC show aired, it suddenly came to light that Allen did “not like the taste” of the glue that was on the stamps and that he therefore never licked his own.  Mr. X’s presumed knowledge of saliva testing can seemingly be established on much more solid grounds than can Allen’s dislike for the taste of glue.

WHERE DO WE GO FROM HERE?

So how can we ever get to the truth about who Zodiac was?  There is at least one good way to get DNA that almost definitely comes from the person who wrote the “Stine letter” of October 13, 1969.  This crucial evidence was first shown to the public on the ABC broadcast in 2002.  As part of their show, ABC showed that in 1996, SFPD discovered by complete chance a small reddish-brown hair stuck in the glue of a stamp on the “Stine letter.”  In fact, in terms of DNA in the Zodiac case, this piece of evidence seems to overshadow the questionable fragment of DNA that SFPD currently has in its possession.

In a case where SFPD’s lab is dealing with a group of potentially contaminated letters, the hair that they found behind that stamp is another beast entirely. The reason the hair was discovered by chance is simple:  It was completely covered by the stamp and was not even visible from the outside of the envelope until the stamp was peeled back by a technician in SFPD's lab in 1996 as part of preliminary DNA work.  The hair was therefore protected from the outside world for about twenty-seven years before this chance discovery turned it up.  This in and of itself should make it a sample that has a high priority for being run for a special type of DNA called “mitochondrial DNA,” even if the DNA found is only used very conservatively for inclusion.  The benefit to analyzing this sample is that it is one of a kind and would only cost between $1,500 and $2,000 to run, so it will represent an undue expense for SFPD to have it analyzed.  (My own feeling is that SFPD could find a lab to assist them for no charge in order to have a hand in possibly solving the Zodiac mystery.)

Here is why I feel that the DNA from this hair is of critical importance:  Since stamps in 1969 were not self-adhering, we know that in order for the glue to have been receptive to catching and retaining this hair, it had to be activated by someone wetting it in some way, presumably by licking it.  Therefore, the hair logically had to be placed on the stamp in the very short window of opportunity between the time that the stamp was licked and the time it was placed on the envelope.  That is clearly only a small time span of a few seconds. 

From the Stine eyewitnesses, we know that Zodiac had reddish brown hair.  The hair behind the stamp is also reddish-brown.  Therefore, it should be obvious to anyone that unless we are so unlucky as to have had the intervention of a postal clerk that also had reddish-brown hair, and who licked the stamp, placed it on the envelope for the killer and in doing so deposited one of his own arm hairs on the stamp, this hair probably comes from the person who wrote the letter.  This in and of itself makes the hair a valuable piece of evidence.

POLITICS AHEAD OF TRUTH?

A major question is why SFPD has not simply analyzed more Zodiac letters for DNA.  Why did they decide to shut down their investigation just when modern technology proved that it was up to the task of developing DNA from a Zodiac letter?  Why didn’t DNA research go into high gear in 2002, instead of being shut down completely?  The answer may surprise people who are not educated about how SFPD works.

For years, SFPD has solemnly stated that “forensics” will solve the Zodiac case.  “DNA” can be effectively substituted for the word “forensics” in this case.  However, despite all the bluster, until the glare of ABC’s lights and cameras showed up in their lab, SFPD apparently did not have even one piece of DNA (of which the public is aware, anyway) from a confirmed Zodiac letter (unless the 1978 letter is now considered a “confirmed” Zodiac letter) to show for all of the Zodiac evidence it possesses.  SFPD reportedly has discretionary control over all of the Zodiac evidence.  This came about because there was never any official “Zodiac Task Force” that would allow the departments equal access to the Zodiac letters.  Therefore, if SFPD is not analyzing the letters, they are not being analyzed.  Period.  And SFPD apparently chooses not to analyze the letters for their own reasons.

After the ABC show aired, I tried to rationalize in my own mind what could be preventing SFPD from trying to develop crucial evidence in its most famous unsolved case.  I knew that there had apparently been no DNA analysis going on before ABC arrived.  After they left, the DNA work seemed to magically stop.  The case was “closed” and the letters were apparently put away despite the excitement of the lab personnel demonstrated on the ABC show.  For years, SFPD has stated that “manpower shortages,” “money shortages” and the exigencies of modern crime all conspired to prevent them from doing work on the Zodiac letters.  None of this seemed to ring true to me.  I decided that the only thing that could possibly be preventing them from devoting any time or resources at all to the Zodiac was had to be just one factor.

I decided that SFPD was playing political games with the Zodiac evidence.  Its policy appeared to be to talk about the importance of DNA evidence but never to do anything to develop DNA in its most famous unsolved case.

Since my suspect had been “eliminated” on national TV by the DNA, I was, naturally, ignored when I said this.  People felt that I was just embittered by the fact that the DNA seemed to close the books on my ideas.  But then in late 2005, webmaster and Zodiac researcher Tom Voigt interviewed the late Inspector Maloney on his web site: http://www.zodiackiller.com/ZStatus.html , who was by then retired from SFPD.  He had worked on the Zodiac case up until the time it was closed down in April 2004.  Insp. Maloney stated publicly that internal SFPD politics were stalling and delaying the analysis of the Zodiac evidence for DNA. He even named a lieutenant who was apparently a key figure in delaying the development of evidence: Lt. John Hennessey.  I immediately felt vindicated by his statement, which confirmed my beliefs:  Insp. Maloney proved that I was on the right track all along when I felt that the excuses SFPD was using were a smokescreen.  After all, if SFPD were serious about solving this case, they would have found a way to fit the Zodiac samples into their schedule, even if it meant the paying their employees the same overtime that ABC was able to inspire.  To cite an old saying that seems to apply here, “Where there is a will, there is a way.”

Just why SFPD does not want to solve the Zodiac case, or at least bring the investigation into the 21^st Century, is a mystery to me.  It may have to do with the fact that SFPD committed many mistakes in its investigation and does not want to see those mistakes paraded in public, should DNA be developed and it leads to a widely covered court trial.  (Note: It should be recalled that in the previous section, I noted that ABC News learned from a source at SFPD that the department apparently does not want the case ever to see the light of day in a courtroom.)  

The title of the article that the Chronicle wrote on my work in 2002 was, “Amateurs Stir Embers of Notorious Zodiac Case.” The title of an article about SFPD in 2007 might be more appropriately titled, “SFPD Tries to Sweep Embers of Zodiac Investigation Under the Rug.”  In having complete discretionary control over all of the Zodiac letters, SFPD has been permitted to become the fox that guards the proverbial henhouse of evidence. 

For years now, I have felt that just as it took the glare of lights from ABC to get SFPD to relent in its political games and develop one piece of DNA, so too will it take another investigative reporter in 2007 to shine a new light on the department and force it to do the job it is paid to do.  My own feeling is that ABC’s show carried with it the implied threat that if SFPD did not cooperate and work with the network to develop DNA, the department would receive negative publicity when the show ultimately aired.  Uncomfortable questions would be asked as to why the department refused to cooperate with ABC News.  SFPD is a political department that does not want to see its image damaged in public any more than it has been its recent scandals (Fajita gate, etc.).  I feel that similar pressure now needs to be brought to bear on SFPD from a new investigative reporter, who can force the department to develop the DNA from the reddish-brown hair and extract some mitochondrial DNA which may be the key to solving the Zodiac case once and for all.

As stated above, the Zodiac case may hinge on only one sample of evidence now.  If money is indeed a limiting factor for SFPD, then this is great news.  Since the reddish-brown hair from the stamp matches the hair color described for the killer in 1969, this one sample seems to represent the most “bang” that this apparently cash-strapped department can get for its analytical buck.  The public should no longer accept the pat excuses proffered by SFPD with regard to the Zodiac evidence.  Even one of its retired Inspectors has admitted that politics are what is delaying the truth in this case.  This should be a wake-up call to everyone interested in the Zodiac case that there is an agenda at SFPD that runs head-on into a search for the truth about the identity of the Zodiac killer.

Unfortunately, SFPD represents the single biggest obstacle in getting to the truth about who the Zodiac killer was.  SFPD is holding a solution to the mystery hostage and with that it is continuing to delay justice for Zodiac’s many victims, which now can even include some Zodiac researchers who have had theories on who the killer was that date back over thirty years!  It is time for SFPD to be forced to relinquish its grip on the Zodiac evidence and give it to a lab that will develop as much DNA evidence from it as is possible using current technology.  That will only happen if enough pressure can be exerted by the public.  For that, the case desperately needs an investigative reporter to represent the interests of the general public against the suffocating politics of SFPD.  Put quite simply, SFPD can no longer be trusted to act in the interest of the public it serves with respect to the Zodiac case.

Update October 7, 2007:

Earlier this year (and obviously in response to public pressure that was brought about by the release of the David Fincher film, Zodiac) SFPD gave the three envelopes that contained Zodiac's first cipher message from July 1969 to the Vallejo Police Department for DNA analysis by the California Department of Justice.  These letters were returned to SFPD from a "private collection" in 2002, in response to the publicity surrounding the ABC Primetime show.

As someone who has done a lot of research on the so-called "Zodiac DNA," I remain highly skeptical of DNA work on the Zodiac letters for the simple reason that after analysis of all of the Zodiac letters that SFPD had in its possession in the 1990s, it was determined that apparently the stamps were applied to these envelopes with water and the flaps were sealed in the same manner (see the discussion from my interview with a former SFPD Criminalist in "Zodiac Letters and DNA").  I feel that SFPD knows that in general the Zodiac stamps were applied with water (i.e., since one of their own former Criminalists did the analyses in the 1990s!) and that if DNA analysis of the three July 1969 letters were going to be fruitful, they would have carried out the analyses themselves.   I also have to think that SFPD would have tested the new letters for the presence of saliva as soon as they received them and if it were present in abundance (unlike in the Zodiac letters analyzed in the 1990s), SFPD would have analyzed these letters themselves for DNA after 2002.  The fact that they turned these letters over to DOJ instead of conducting the analyses in the months leading up to the publicity surge brought on by the release of the movie, did not bode well (in my mind, at least) for the possibility that any DNA would be extracted from these letters.  My feelings were seemingly confirmed in about June 2007, when the results of the analyses were released and the DOJ announced to the public that it was unable to isolate DNA from any of the letters.

Until such time as someone from law enforcement can prove that a laboratory has isolated identical, overlapping allelic sequences of DNA across several different Zodiac letters, I will remain skeptical of the source of the so-called "Zodiac DNA." 

Over the years, DNA has clearly become a crutch for law enforcement in the Zodiac case, as well as many other cold cases.  The easiest thing for a Homicide Cold Case detective to do is to sit in his or her office with their feet on the desk and wait for DNA to solve the case: Why interview anyone in an old and complex mystery like the Zodiac case, if the DNA can simply solve the case for you?  However, when you have a man like Mr. X who is still living and who seems to be telling a story about the night of the Stine murder that is glaringly inconsistent with Officer Pelissetti's version of the events of that night, it is necessary for a detective to get up from that desk and go out to interview this man, instead of permitting such a task to fall onto the shoulders of civilians like me and Jim.