ZODIAC DNA: A Question of Answers

San Francisco’s Old Mint recently hosted a special screening of the 2007 film ZODIAC. Attending the event were San Francisco Chronicle writer Kevin Fagan, retired San Francisco Police Captain Al Casciato, and SFPD Inspector Pamela Hofsass.

Sandy Betts attended the screening and described the event in her message board posts. According to Betts, Hofsass told the audience that the San Francisco Police Department has obtained a partial profile of the Zodiac’s DNA. The same news was reported over a decade ago when the San Francisco Police Department announced that it had obtained a partial DNA profile from Zodiac communications. Then, investigators explained that the partial DNA profile would help to exclude suspects but could not be used to positively identify the Zodiac. The same would appear to be true today, as a partial profile can only eliminate an individual as the donor of the DNA. The partial profile cannot positively identify the Zodiac because the profile is incomplete. The DNA of a suspect may appear to match the partial profile but testing cannot accurately complete that match without a complete DNA profile from the Zodiac communications or other evidence. Until a complete profile is obtained, the new DNA profile may prove useful in reducing the ever-expanding list of suspects and clearing some of the confusion which continues to cloud this case.

Members of the Zodiackillersite message board wondered if Hofsass was referring to a “new” DNA profile or the same partial profile previously obtained from Zodiac envelopes in 2002. The questions prompted Sandy Betts to post a clarification which read: “I don’t want people to come to the the wrong conclusion as to what I said. (I need to make it more clear.) The DNA is a “partial” and with technology advancing as fast as it is, I was told that it can be used in the near future, not today or tomorrow but near future. Because it is only a “partial” it can not be entered into CODIS.”

In 2002, SFGate reported that the SFPD had obtained a partial DNA profile from suspected Zodiac communications. The article quoted SFPD Inspector Kelly Carroll: “We have something we haven’t had to this point, a partial DNA fingerprint.” Carroll conceded that profile was “not enough at this time to submit” to CODIS (Combined DNA Index System).

In a 2002 CNN interview, Carroll stated,”Well, in the instance of this case, as I said, Zodiac mailed letters to the local newspapers. Now, he claimed to have disguised his appearance and to have disguised his fingerprints so that police couldn’t find him. But one of the things that we did in examining the evidence is realize that in 1969 the idea of DNA was at best science fiction and so it was probable that Zodiac did not have any idea about disguising or hiding his DNA. And so we concluded that there was the possibility that we could recover biological material deposited by Zodiac when he licked the stamps and the envelopes that he used to send the letters.”

I spoke to Kelly Carroll in 2000, when he had been assigned to the Zodiac case along with his partner, the late Mike Maloney. Carroll was optimistic about the potential of modern forensic technology and said, “If this is case is solved, it will probably be solved by someone in a white lab coat.” Carroll and Maloney worked to process Zodiac evidence for possible DNA, and it’s encouraging to see that the San Francisco Police Department is still trying to solve the case after all these years.

DNA evidence proved invaluable in many cases, often serving as the last word which either identifies the guilty party or exonerates the wrongly accused. DNA evidence has exonerated at least 300 people including Damon Thibodeaux, who was recently released after serving more than fifteen years in prison for the rape and murder of his step-cousin.

DNA evidence has raised new and disturbing questions regarding the convictions of the so-called “West Memphis Three,” who had been imprisoned for the murders of three young boys but were recently released by a controversial Alford plea. Damien Echols, Jason Baldwin and Jessie Misskelley conceded that the prosecution possessed evidence to convict them in court, and, in exchange for their guilty pleas, the trio was released after serving eighteen years in prison. The case received renewed and increased scrutiny when newly-obtained DNA evidence appeared to implicate the step-father of one victim.

DNA evidence finally settled a decades-long debate regarding the guilt or innocence of accused “Boston Strangler” Albert DeSalvo. After a series of unsolved murders, DeSalvo claimed responsibility in confessions which were later challenged by those who doubted DeSalvo’s guilt and questioned the official conclusion that he alone was responsible for all of the murders attributed to the same strangler. Previous attempts to obtain DNA evidence from the body of an exhumed victim raised questions when the discovered evidence did not appear to match DeSalvo’s DNA. However, new testing has now proved that DeSalvo’s DNA was found on the body of the last strangler victim Mary Sullivan. The Sullivan family had questioned the DeSalvo solution for many years, and nephew Casey Sherman authored a book which suggested that other suspects may have been responsible for the Boston stranglings. Upon learning the news that new DNA evidence implicated DeSalvo in his aunt’s murder, Sherman conceded DeSalvo’s guilt and said, “I only go where the evidence leads.” He also he thanked investigators for their “incredible persistence.” History has apparently closed the book on the enduring mystery of the Boston Strangler, leaving other great mysteries awaiting their final answers.

Renewed efforts to obtain DNA evidence could provide surprising results which may implicate previously-dismissed suspects or exonerate others who many had claimed were undoubtedly guilty. When the San Francisco Police Department announced that suspected Zodiac DNA did not match the infamous suspect Arthur Leigh Allen, his accusers dismissed the evidence and continued to claim that he was somehow involved in the Zodiac crimes. The results of DNA evidence are usually ignored by those who accuse suspects excluded by that DNA evidence, so the new partial profile may do little to discourage amateur sleuths who are convinced that their suspect was the Zodiac killer.

News of possible DNA evidence raises hopes that we may someday have answers to some of the questions which persist in the ongoing debate about this case. Can DNA from the Zodiac communications be matched to the DNA from other writings and thereby prove that one individual was responsible for all of the suspected Zodiac letters? Will DNA taken from the Zodiac communications match DNA linked to other Zodiac crimes? Can the new DNA confirm or exclude a link between the Zodiac letters and writings related to the still-unsolved murder of victim Cheri Jo Bates?

I have followed and researched this case for a very long time, and I would be thrilled to see new evidence identify the Zodiac, but that may prove difficult if the Zodiac is not one of the known suspects and his DNA profile is not contained in the CODIS database. I hope that Inspector Kelly Carroll was right when he predicted that the case would be solved by forensic science. After more than four decades, this unsolved mystery needs to meets its end.


CHERI JO BATES and The ZODIAC: Unsolved Crimes and Unanswered Questions


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