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November 3, 2018

The Unsolved Mystery of the Zodiac Killer

Winner of the Fall 2018 StMU History Media Award for

Best Article in the Category of “Crime”

Best Article in the Category of “Political History”

Robert Graysmith, a cartoonist working for the San Francisco Chronicle in 1969, developed an obsession to discover who the Zodiac Killer was. On a rainy night he received an image of a driver’s license of a man named Arthur Leigh Allen. On this license was Allen’s date of birth, December 18, 1933. This information became the final clue in Graysmith’s investigation, allowing him to put all the pieces together to discover the identity of the Zodiac Killer.

On August 1, 1969, the first letter written by the Zodiac Killer was delivered to the San Francisco Chronicle. The letter was a confession to the murder of two teenagers, Darlene Ferrin and Michael Mageau, on July 4, 1969, at Blue Rock Springs Park in Vallejo, California.1 A cypher was attached to the letter and the killer demanded that his cypher and letter be published in the newspaper, threatening to kill more if the paper did not do so. This letter and the cypher that came along with it was the initial spark that led Graysmith into his obsession with finding out who this Zodiac Killer was. He himself tried to decode the cypher by reading different books involving code breaking, but was beaten to solving it by Donald and Bettye Harden, who solved the code themselves. Within the cypher, it talks about “man [being the most] dangerous animal of all.”2 Graysmith discovered that this line was from the movie The Most Dangerous Game, which is about a man who hunts people for sport. Nonetheless, this became Graysmith’s first piece of evidence to be discovered from the Zodiac Killer’s letter; yet, it wasn’t until seven years later, in 1977, when Graysmith started adding up the evidence that would pointhim to Arthur Leigh Allen as the Zodiac Killer.

Darlene Ferrin murdered by Zodiac Killer and Michael Mageau who was wounded by him July 4, 1969 (Blue Rock Springs Park. Vallejo, CA) | Courtesy by Wikipedia

Arthur Leigh Allen had a friend named Don Cheney, who provided information that pointed to Allen as the prime suspect in the investigation. Cheney had mentioned that on “September 27, 1969 in Napa, California, Allen [had told his family] he’d be leaving for the afternoon to go scuba diving at Lake Berryessa.”3 However, later that day Allen returned home covered in blood with a bloody knife found in his car. That same day a police report was filed for one murder that involved the killing of Cecelia Shepard, age 22, and although Bryan Hartnell was a victim in the attack that killed Shepard, he was able to survive. 

Image of Zodiac Killer in his “murder suit” killing Cecelia Shepard and Bryan Hartnell | September 27, 1969 (Napa, CA) | Courtesy of Wikipedia

Allen’s same friend, Don Cheney, also confessed that Allen referring to himself as the “Zodiac” before the publication of the letters, and even before the murders had taken place. Allen not only referred to himself as “Zodiac,” but also wore a Zodiac brand watch. The police further investigated him by searching his trailer, but “only [found] small dissected animals, bloody knives and sexual devices.” 4 None of this, however, was direct evidence linking Allen to the murders. Although he was not convicted for murder, he was separately convicted of child molestation resulting in a three year sentence in prison. Coincidentally, no Zodiac letters were sent during this time to the San Francisco Chronicle. Additionally, during his time in prison, one of Allen’s inmates reported to the police a confession Allen had told him. Allen reportedly took responsibility for the murder of Paul Stine, a taxi driver who was shot in the head by his passenger. This murder was also mentioned in one of the Zodiac’s letters. Right after this incident, an interview on national television by Melvin Belli had tried to elicit a confession from Allen for the murders, but unsuccessfully. Afterward, the Zodiac Killer tried to reach out to Belli by calling his house on December 18, 1969. Belli was unable to answer, but his maid did. She stated that all the Zodiac Killer said was, “It’s my birthday, I must kill.”5 A chilling, yet important fact in the investigation.

Letter to call himself the Zodiac Killer including his signature mark | August 1, 1969 | San Francisco, CA | Courtesy of Wikipedia

One piece of evidence that seemed to sealed the deal for Graysmith that Allen was the Zodiac Killer was Graymith’s interview with Linda Ferrein. Graysmith sought to question Darlene Ferrin’s sister, Linda Ferrin, to find out whether there was any correlation with her sister and the Zodiac Killer, due to a piece of information referencing Darlene’s painting parties in one of his letters. As Graysmith interviewed Linda, she described Darlene as always being surrounded by boys. But there was one in particular who stood out to her. Linda described this boy as antisocial when he attended one of Darlene’s painting parties. Darlene also warned Linda to stay away from him because she said he scared her, and also mentioned to her sister that this was the same man who confessed to her he had killed someone. Not only that, but he had a nickname for himself, which was Leigh, which was also Allen’s middle name. During that same time, Graysmith received an image of Allen’s driver’s license confirming Allen’s date of birth, December 19, 1933, the same date on which he made a phone call to Melvin Belli stating, “It’s my birthday, I must kill.”6 All of this piled up evidenced convinced Graysmith that Allen was the Zodiac Killer, because this was the only time that the Zodiac Killer gave out a piece of personal information. Unfortunately, authorities planned to have a meeting charging him with all these murders, but Allen suffered from a heart attack before the meeting could take place. 

Image of Arthur Leigh Allen’s driver’s license | San Francisco, CA | Courtesy of Wikipedia

Convincing enough? This is one of the most popular theories from Robert Graysmith who believed the serial murderer was Arthur Leigh Allen. Although there is supporting evidence that points towards him as the killer, many question Graysmith’s judgment and overall investigation. Regardless, the case still remains unsolved and we may never know who the real Zodiac Killer was. Was it Arthur Leigh Allen or was Graysmith’s theory further off than we thought?

  1. William Booth, “The Zodiac Writer,” The Washington Post, Mar. 09, 2007, (accessed September 5, 2018).
  2. Robert Graysmith, Zodiac (Penguin Publishing Group, 2007), 78.
  3. William Booth, “A Killer Obsession,” The Washington Post, Mar. 1, 2007, (accessed September 5, 2018).
  4. Justin Moyer, “And the Zodiac Killer is…,” The Washington Post, May 14, 2014, (accessed September 7, 2018).
  5. Robert Graysmith, Zodiac unmasked (New York: Berkley Books, 2003), 180.
  6. Robert Graysmith, Zodiac unmasked (New York: Berkley Books, 2003), 180.

Nathalie Herrera

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Recent Comments


  • Kimberly Rubio

    The images included added to the quality of this article. I have heard of the Zodiac Killer, but I did not know there was a prime suspect. What was most interesting to me about this serial killer was his obsession with the media. He demanded publication from a major news publication. He wanted the attention. I think he almost wanted to get caught. I think he wanted to be remembered. I only say this because he left the clue regarding his birthday. It is unfortunate that his friend never came forward with the information he had. I wonder if he was prosecuted for this.

  • Jacqueline Guardia

    My major is Forensic science/criminology. I like reading about crime investigations, and theories about the zodiac killer are interesting. It is still scary that we don’t know who the zodiac killer was. The fact that if we use the same characteristics that Allen had, like age, The zodiac killer would be 87 years old now. This article had me at the edge of my seat. Well written with details and dates, Great article.

  • Franchesca Baldwin

    Like with the most well-known crime investigations, I have heard of the zodiac killer but not know much other than the basics that surrounded him being a serial killer. It’s sad to Think that at least one of his victims was admittedly wary of him, even scared. Sometimes intuition is an important thing to trust, And that watching out for yourself or someone else isn’t judgment. Either way I’m convinced that Graysmith Had found the guilty man, though justice was never truly served.

  • Mia Hernandez

    This article was very chilling but very interesting. I don’t like scary events or articles but I could not stop reading this one. I have heard about the zodiac killer but I was not informed about his life. I think it is very interesting that no one knows who the killer was after there was so much evidence tied to one person. It is terrifying to know that these cases are still unresolved. The zodiac killer was a very creative killer and had unique strategies for his murders.

  • Sophia Rodriguez

    This was super interesting because I have heard about the Zodiac Killer, but never knew much information about him. I thought it was interesting how he confessed to killing someone and gave out his private information that could have potentially given him away to the police. This could have also just been another serial killer out their that wasn’t even the Zodiac Killer. This article really makes you wonder if the killer is still out there just as another name or did the killer die and we never found out it was truly him.

  • Melanie Fraire

    I’ve heard about the “Zodiac Killer” multiple times before however nothing I have read was as informational as this article. I knew some basic knowledge regarding the zodiac killer such as his crimes however, this is the first time I’m hearing that there was a suspect with this much evidence that linked the murders to him and after reading this article it’s pretty shocking that it’s still unknown as to who the killer is since the evidence seems to be pretty good. But at the same time I agree there’s still some major evidence missing to have convicted the guy.

  • Aracely Beltran

    I was actually more scared of reading this and the letter than when I watch any paranormal movie, ever. I got chills! Especially because it is still unresolved, that scares me the most. I cannot believe that there was someone who was actually sneaky enough to kill without being caught. How unpeaceful it must be for the family, knowing their killer never was caught. Great article!

  • Mia Hernandez

    I have watched crime shows with episodes about the zodiac killer as well as watched a couple movies about him. The main points that I remember was that he had sent police letters with encrypted messages as well as that there wasn’t a definite identification for the killer. What I don’t recall is the man mentioned in the article- Arthur Leigh Allen, being a suspect for the zodiac killer. As Graysmith was obsessed and determined to solve the zodiac investigation, I can see how he might have tied in Allen to the crimes, but we may never know who the actual zodiac killer is and if Graysmith’s judgment had been clouded with obsession.

  • Malik Heard

    I have heard of the zodiac killer because he is one of the most infamous serial killers in america.I was already pretty well informed before I read this article from other articles and youtube videos about him.It was pretty interesting seeing the theory Graysmith’s and the differsnt views people have on the zodiac killer. Im glad that killers like this aren’t as successful anymore and are caught before they can cause mass damage.

  • Jose Chaman

    This article has been very well written. I didn’t know the story of the killer “Zodiac” and I found it very interesting how this investigation was never fully resolved. Allen may have been the culprit, because all the evidence indicated that. However, thanks to scientific development, we now have better investigation mechanisms, this ensures that impasses like these never happen again and cases can be resolved.

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