Dec. 20 (UPI) -- One of the strangest, most high-profile serial killers in U.S. history -- spawning books, TV programs and movies -- began his reign of terror 50 years ago Thursday, killing two teenagers in a San Francisco Bay Area community.
The teens were shot dead in the dark by a shadowy gunman who'd later taunt Northern California for years with letters and phone calls. To this day, the only thing known about him is his chilling moniker -- the Zodiac -- and what he might look like.
With the help of modern science, authorities are still trying to find out who he is.
The Zodiac murders
The first known killing associated with the Zodiac took place Dec. 20, 1968, when 17-year-old David Faraday and 16-year-old Bettilou Jensen were found shot dead while on their first date on Lake Herman Road, considered then a lover's lane, 25 miles northeast of San Francisco in Benicia, Calif.
Faraday's body was found riddled with gunfire beside his station wagon. He'd been shot in the head at close range by a small-caliber bullet. Jensen was found about 10 feet away, shot in the back five times.
On July 4, 1969, he struck again -- attacking 22-year-old Darlene Ferrin and 19-year-old Michael Mageau at Blue Rock Springs Park in Vallejo. He lived, she didn't.
In the case's first bizarre turns, the killer phoned police to report the crime -- and wrote three Bay Area newspapers with knowledge of the killings only the perpetrator would know. In the letters, he also took credit for the December 1968 attack in Benicia.
A few weeks later, he struck again. Another young couple -- 22-year-old Cecilia Ann Shepard and 20-year-old Bryan Hartnell -- were stalked by the killer while picnicking at Lake Berryessa in Napa County. The killer sprung from woods, dressed in a bizarre suit and executioner's hood, and stabbed the couple. Again, the man survived, the woman did not.
The killer again confessed to the slaying in a phone call to police -- and scrawled a morbid message with a marker on the passenger door of of Hartnell's Volkswagen Karmann Ghia. It denoted the previous two killings and the date, time and method of the new attack: "Sept 27-69-6:30, by knife."
The final death officially attributed to the Zodiac broke from the previously established pattern, as he fatally shot cabdriver Paul Stine in the Presidio Heights area of downtown San Francisco on Oct. 11, 1969.
A couple of days later, he sent another taunting letter to The San Francisco Chronicle with new proof of his complicity -- a blood-stained swatch of Stine's shirt.
It was at the Presidio crime scene police got their first real break in the case -- a physical description that led to a composite sketch of the elusive killer. A group of teens who witnessed Stine's death said the gunman was a white man, age 25 to 30, about 5-feet-8 with a crew cut and thick-rimmed glasses. The sketch remains the defining image of the killer.
50 years of intrigue
Dating back as far as the first killings, the Zodiac captivated the attention of the world.
"For me, the Zodiac case is the number one unsolved American criminal mystery," Mark Hewitt, a California-based author who has published a trilogy of books on the killer, told UPI. "It is America's Jack the Ripper, basically. I think there are more people looking into this case than any other case."
Part of the intrigue stems from the fact that, in addition to his letters to authorities and news media, the killer sent a series of cryptograms that contained grisly messages when deciphered.
The first cryptogram was sent in three parts to the Chronicle, San Francisco Examiner and Vallejo Times-Herald. When it was broken, it revealed a message describing the pleasure Zodiac derived from his crimes -- including the passage, "I like killing people because it is so much fun ... it is more fun than killing wild game in the forest because man is the most dangerous animal of all to kill."
This, however, was the only cryptogram that was ever definitively decoded. In one of the unsolved puzzles, the Zodiac said, was his name.
The Chronicle received and published another cryptogram on Nov. 12, 1969, along with a letter claiming responsibility for two additional murders outside of the five officially attributed to him. Zodiac continued to send letters, post cards and other taunts, possibly as late as 1978. He ultimately claimed 37 murders, but authorities came no closer to uncovering his identity.
The overall lack of information and the killer's flashy methods have also added to the mystique surrounding the case. It's spurred a number of legends and conspiracy theories regarding the killer, and debate over the circumstances that have prevented him from being unmasked all these years.
"There's a whole lot of mythology that has made its way into the case, there are all kinds of stories and all kinds of facts that are untrue and completely fabricated that have attached themselves to the case over the years," Hewitt said. "So, a big part of researching it is to find out what did happen and what mythology is untrue about the case."
Hewitt said one theory that evidence seems to debunk is that different people were responsible for the killings and the letters.
"The evidence in the letters makes it quite clear, the relationship between the different crime scenes and the letters show that one person is involved and only one person," he said. "The police readily accepted that and worked on the case in the 1970s with that understanding that it was one person. And this person kept writing and the letters contained information that was known only to the perpetrators and the police."
The mystery continues
For a time, police believed a convicted child molester from Vallejo may have been Zodiac. He died in 1992 and a 2002 DNA test seemed to rule him out as a suspect. Technology at the time, though, didn't allow for a clean sample to be extracted from the glue on envelopes the killer used to send the letters.
In 1996, authorities also briefly explored the possibility that Unabomber Theodore J. Kaczynski was Zodiac. The investigation didn't produce enough evidence to implicate Kaczynski.
San Francisco Police Lt. John Hennessey, declared the case inactive in 2004 after the inconclusive DNA test, but authorities ramped up their efforts this year, inspired by the capture of the Golden State Killer.
Although the Zodiac's last confirmed kill took place in 1969 and his last confirmed message came in 1974, Bay Area law enforcement agencies are still working to crack the case. And they are hoping modern methods will help them do it.
In May, Vallejo police turned their attention to DNA and genealogy -- hoping to solve the long-cold cases the same way authorities said they finally unmasked the Golden State Killer. A suspect was identified by police after they ran DNA from crime scenes through genealogical databases, like Ancestry.com and 23 and Me, which identified possible familial lineage.
Unlike the Golden State case, though, much of the Zodiac evidence has been compromised after being mishandled by the original detectives.
Vallejo Police Detective Terry Poyser said his team has resubmitted two Zodiac envelopes to a lab for new analysis, hoping to test the results against an expanded pool of samples used in genealogy research.
The results of both inquiries are pending.
There's also a chance the case could be solved by more traditional methods.
"There are about half of a dozen different police agencies that continue to get tips from the public in the order of several a week -- even today, 50 years after the murders," Hewitt said.
But after five decades, time is running out. Many of the original witnesses and investigators are in advanced age or dead -- including the Zodiac, whoever he is.
"It was an unsolved case and yet by all accounts it should have been solved because the perpetrator left behind so much evidence that he really ought to have been caught," said Hewitt.
"It's kind of freaky that he hasn't been."
Edit: A previous version of this story mentioned that Sacramento County investigators also submitted a Zodiac DNA sample from a crime scene to GEDmatch. The mentioned samples actually belonged to the Golden State Killer. The story has been edited to reflect this.