Allen was known to dislike licking stamps, according to the Web site, zodiackiller.com, so the police compared the saliva DNA to a close associate who had once told investigators many of the details that had put them on Allen’s trail in the first place. That man was eliminated as well.
Allen’s palm print did not match prints lifted from Zodiac-related items, either, or his handwriting. In fact, there has never been a way to conclusively pin the crimes on him.
But there have been other good suspects, too, who have fallen by the wayside. There was stocky, bespectacled, former navy man Richard Marshall, a movie buff and fan of Gilbert and Sullivan musicals. He had a bad temper and was hostile toward women; he also had training in codes and could sew.
More interesting was the suspect identified by Gareth Penn, a Zodiac buff who spent an inordinate amount of time with the binary calculations and codes in the Zodiac letters, both authentic and perhaps not so. He pinpointed an academic on the East Coast who often traveled to the relevant areas.
In addition, we’ve heard about links to a former member of the Manson family, to Theodore Kaczynski, to a man identified by his own brother as the enigmatic killer, and even to the Beltway Snipers. Nearly four decades after the initial crimes, it’s become a regular obsession for some people to try to figure out the Zodiac’s identity. A few have even shouldered the challenge of revisiting the mathematical calculations, noting the errors made in earlier attempts, but so far, these efforts have proven nothing conclusive.
Many still favor Allen as the suspect and explain away the lack of matches to physical or biological evidence, saying he had an accomplice who sent the letters. It’s hard to give up a theory on which one has spent so much time and energy.
In any event, in 2004, the SFPD officially made the case “inactive” for the murder of cabdriver Paul Stine, citing workload and lack of leads. The other murder cases remain open.
Like that of Jack the Ripper, this case remains in limbo until police can develop a full DNA profile that matches someone, and also like Red Jack’s spree, it will probably inspire mystery buffs in the future to name suspects not yet imagined. Yet as any of the nearly 200 falsely convicted people who have been exonerated with DNA evidence can tell you, even a seemingly comprehensive totality of logic and circumstances can be misleading.