Top 10 Mysterious Zodiac Killer Facts

Historians and true crime buffs alike are dying to know the identity of The Zodiac Killer, and as a result, the case has largely entered the public consciousness. So, it sort of makes sense that the details of the case would be ripe for dramatic adaptations. There's David Fincher's "Zodiac," course, as well as a "Criminal Minds" episode that dealt with a Zodiac copycat. The character Scorpio in the classic Clint Eastwood flick "Dirty Harry" was not only based on Zodiac, but the film's 1971 release date meant that the case was still making news rounds. Lower-budgeted exploitation pictures like "The Zodiac Killer" and even an adult film parody starring John Holmes jumped on the story with even more of an opportunistic edge.

Police have gone on record with a total of seven victims directly linked to The Zodiac Killer, with two having survived their encounters. However, letters from Zodiac stated the true number as 37! Is this true? Well, there are cases with potential ties to the killer's patterns and whereabouts during the 1960s, with one couple, Robert Domingos and Linda Edwards, being attacked and killed as early as 1963. Fast forward to the early seventies, and Zodiac's name came up once again as a potential suspect in a series of grisly assaults on hitchhikers in two California counties, dubbed the Santa Rosa Hitchhiker Murders.

The murder of cabbie Paul Stine was something of an outlier in the Zodiac case, a seemingly random attack where Zodiac took Stine's wallet and keys before mailing a piece of the driver's bloodied shirt to police. What's even more confounding is the immediate aftermath of the murder, where a police APB mistakenly listed the subject as a black man instead of the Caucasian-with-a-crew-cut image that's most closely associated with the Zodiac's appearance. Two patrolmen actually had a brief encounter with someone matching that latter description while they were on the scene, an exchange that Zodiac later referenced in a letter, mocking the ineffectualness of the police investigation.

We often desire our darkest mysteries to have some sort of open-and-shut answer, a way to rationalize reprehensible behavior in our brains so that we can lay blame solely on the feet of a suspect or suspects. Unfortunately, the Zodiac case was never going to end this way, despite the list of potential Zodiac suspects and their tenuous links to the crimes via circumstantial evidence. Arthur Leigh Allen was the closest thing police had to a sure thing, but was cleared via DNA, fingerprint and handwriting evidence. This was despite some direct evidence to the contrary from surviving Zodiac victims, including Mike Mageau, who pointed to Allen in a police lineup, and Bryan Hartnell, who claimed that the voice and physical demeanor matched up with his attacker.

The Zodiac case was already complex enough for police. But one aspect that complicated things even further was the Killer's habit of sending codes via ciphers, a form of communication that’s deliberately disguised in order to convey a hidden meaning. Only one of these four ciphers was ever fully cracked, and it took an outside source, specifically schoolteacher Donald Harden and his wife Bettye, to do the job. The final message honestly didn't reveal much, but it did shed some light on the killer's loose grip on reality, as well as his affinity for cinema, such as "The Most Dangerous Game." The cipher also claimed that the Zodiac's victims would serve him in the afterlife.

The term "modus operandi" can be loosely defined as a particular characteristic or established way of performing a task. This was definitely the case when it came to The Zodiac Killer, who tended to target couples who were parked in cars or located in otherwise secluded areas. Zodiac was meticulous and prepared when it came to stalking his victims and catching them by surprise, often creeping up on them with a knife or firing gunshots at point blank range. The Zodiac also wore a black, executioner's style hood for his Lake Berryessa attack of Bryan Hartnell and Cecelia Shephard, as well as a white bib displaying a 3-inch by 3 inch cross-circle insignia as a sort of perverse coat of arms.

It's not entirely uncommon for true crime authors to offer up theories as to who might have committed a series of unsolved murders. But it's another thing altogether for someone to come forward and claim one of their relatives as one of the most infamous serial killers in American history. This was exactly what happened in 2007 when Dennis Kaufman put forth his stepfather Jack Tarrance as a Zodiac suspect, due to his discovery of a similar looking executioner's hood, as well as a bloody knife and handwriting samples Kaufman claimed would match up with that of the Zodiac. Seven years later, Gary Stewart wrote a book claiming that he was the biological son of The Zodiac, having been abandoned by his biological parents in the early sixties.

Three separate letters were sent in 1969 to three major newspapers in the San Francisco area, each containing one third of a cipher, which Zodiac claimed hid the key to his identity. Less than a week later, another letter was sent to The San Francisco Examiner, opening with the chilling line which has now become the killer's calling card: "Dear Editor, this is the Zodiac speaking..." We already mentioned the cipher cracked by The Hardens, but another code, dubbed, "Z 13" has been at least partially cracked. The note is short, and begins with, "My name is..." But don't get your hopes up, because cryptologist Craig P. Bauer wrote on History.com that he believes the actual answer is a joke: Alfred E. Newman, the mascot for MAD Magazine.

The Zodiac Killer was bold in his communication with both authorities and the press. This wasn't just limited to snail mail, however. An anonymous call was placed via a nearby phone booth to the Vallejo Police headquarters, claiming responsibility for the gunshots that left Darlene Ferrin dead and Michael Mageau severely injured. They’d encountered the Zodiac while parking at Blue Rock Springs, California. There was also a message left on a car door after the Lake Berryessa murders. Zodiac drew his cross/circle calling card, adding to it the morbid details about his knife attack upon Hartnell and Shepard. Zodiac even taunted police in a letter with creepy threats.

Before we name our number one pick, here are a few dishonorable mentions

They May Have Been Multiple Killers
Occasional Deviations in Witness Descriptions Make it a Possibility

There Were Detailed Sketches of Zodiac
Somehow, the Zodiac Still Continued to Elude Police

Some of Zodiac's Victims Are Still Alive
As Time Passes Though, the Zodiac Case Runs the Risk of Becoming an Unsolved Mystery Forever

One of Zodiac's Potential Victims Escaped
Kathleen Johns Jumped From a Moving Car After Being Abducted by a Zodiac Suspect

Cement Was Reportedly Used to Hide Fingerprints
The Zodiac Always Seemed to Be a Step Ahead of the Police

There were numerous copycat crimes, fan letters, and hoaxes after the deaths of Zodiac's five confirmed victims. Phone calls and tips continue to be sent in to this day by those who think they may have the answer. One brief break in the case did occur when authorities managed to extract some saliva from a stamp, but this piece of evidence, while eliminating some subjects, wasn't enough to bring the Zodiac Killer to justice. The final official communication with The Zodiac was received by The Chronicle in 1974, where he expressed his approval of "The Exorcist" as "the best satirical [sic] comedy I've ever seen," before closing his letter with a final running tally which simply said "Me= 37, SFPD=0."