Over the years, the Zodiac case has been “hijacked” in a way. Ironically, instead of being handled like a murder case and using profiling and investigation to solve it, the search has devolved into the type one would normally see in a fraud or blackmail case, where the primary focus is on handwriting, DNA, and palm prints, all of which come from the Zodiac letters, not the actual crime scenes. This has caused a huge distraction from the usual goal of a homicide case: finding the person who behaved like the Zodiac.
Mr. Walter feels that one’s writing can vary according to mood, intent, and desire to disguise. Handwriting can evolve over time too. There are also such unquantifiable variables as the possibility that Zodiac derived his three-stroke K from viewing the Peek-a-Boo Pennington yellow pages ad, which seems to have influenced the structure of the 1970 Avery Halloween card. Therefore, the presence of the three-stroke K may be an effort to disguise the killer’s true handwriting. For these reasons, it can present problems for an investigation when handwriting is given too prominent a role in determining the ultimate guilt or innocence of a murder suspect. Mr. Walter stated that in a homicide inquiry such as this, handwriting can merely serve a confirmatory role, but it should never be used to exclude someone who otherwise had the motive, means, and opportunity to have committed the crimes, which is the premise of this book with respect to Kjell Qvale and the Zodiac’s obsession with money and power.
In the Zodiac case, where the notoriety of the killer’s letters overshadows all other considerations, handwriting is given much too prominent a role. What has unwittingly happened over time is that we have turned questioned-documents experts into de facto homicide inspectors with the power to rule out suspects in a murder case. These exclusions have nothing to do with whether or not the suspect matches the profile of the killer based on his behavior at his crime scenes, or what the circumstances are that tie him to the case. In granting this power, we make a potentially disastrous assumption: that the Zodiac Killer was not that rare individual who could successfully disguise his handwriting. Here’s a quote about Jack the Ripper suspect Michael Maybrick in Bruce Robinson’s 2015 book, They All Love Jack, “But maybe the author of the Jack the Ripper letters had a talent for disguising his handwriting. . . . It’s worth a moment to quote an example of just such a man. . . . He could change his handwriting, or copy the handwriting of others, at will, and was described by authorities at Scotland Yard as ‘the greatest forger they had ever known.’ John George Haigh could write whole letters in the hand of a dozen or more people . . . and at a second’s notice he could switch from one to another.”
So altering one’s handwriting is not as impossible a task as questioned-document experts would have us believe. Maybe uncommon, maybe unlikely, but not impossible. The Zodiac has defied identification for nearly fifty years, so why be so quick to say that successfully altering his handwriting was beyond his capabilities? If John George Haigh could do it, why not Zodiac? That is why you use a behavioral profile and circumstantial evidence, not handwriting, to solve a case.
Retired Napa County Sheriff’s Office captain Ken Narlow told me in 1999, and which Mr. Walter echoed: even when you find the right person in a given investigation, not every piece of evidence is going to fit. There will always be an odd man out—a square piece of evidence that needs to go into a round hole. And in fact, Mr. Walter said that he is suspicious if everything about a suspect fits what’s known about a crime, because that makes it look like the individual may have been “set up” in some way.
For those who believe the Zodiac case will one day be solved via handwriting comparison, you may be interested in the following story: Retired SFPD Inspector Vince Repetto once told me about and incident involving a prominent Zodiac handwriting expert. This expert was handling a case from the East coast that was completely unrelated to the Zodiac mystery. It was the case of a contested hand-printed will. Remarkably, he noticed that the handwriting in the will matched something like 23 of the 26 unique handwriting characteristics of the Zodiac killer. The person who had made out the will had also lived in San Francisco during the Zodiac era.
The expert took the handwriting to the next forensics convention. He showed a side by side of the Zodiac's hand printing and the writing from the will without saying that the known writing was from Zodiac. In a show of hands, apparently ALL of the experts agreed that the two handwritings matched. But when told the known handwriting was form Zodiac, they all lowered their hands.
Why was this the case? In the real world, handwriting experts make their livings on their reputations for never being wrong. If one of them said that the will writer was also the Zodiac killer and if this expert were later proven WRONG in a major case, it would be very bad for business.
So handwriting may not be the panacea in the Zodiac case.
 Bruce Robinson, They All Love Jack, (New York: HarperCollins, 2015), p. 364.