Why has the Zodiac Killer never been caught?

The killer's cipher was cracked in December after 51 years, sparking a wave of renewed interest

By Katie Dowd
SFGate, San Francisco

SAN FRANCISCO — After 51 years, a team of three codebreakers cracked the Zodiac Killer's 340-character cipher in December, sparking a wave of renewed interest and fresh frustration.

Five decades since Zodiac shot teenagers David Faraday and Betty Lou Jensen dead on Lake Herman Road, police seem no closer to capturing the elusive killer. During the course of his brief spree from December 1968 to October 1969, Zodiac killed five, wounded two and sent a number of taunting letters to Bay Area newspapers. His letters turned the situation from terrifying to cinematic, as Zodiac held sway over the region with his bizarre missives.

In this May 3, 2018, file photo, a San Francisco Police Department wanted bulletin and copies of letters sent to the San Francisco Chronicle by a man who called himself Zodiac are displayed in San Francisco.
In this May 3, 2018, file photo, a San Francisco Police Department wanted bulletin and copies of letters sent to the San Francisco Chronicle by a man who called himself Zodiac are displayed in San Francisco. (AP Photo/Eric Risberg, File)

But despite four different crime scenes and plenty of written correspondence, police weren't even able to zero in on a clear suspect, leaving still-frightened Bay Area residents to wonder: Why has the Zodiac Killer never been caught?

Here, we've gathered four of the biggest hurdles to solving the infamous case.

There's no clear-cut DNA evidence

While it's true that a number of high-profile cold case murderers have been brought to justice in recent years, they all have one thing in common: DNA.

The Golden State Killer, for example, left dozens of samples at dozens of crime scenes. Even decades-old evidence can be re-examined with modern technology for blood or semen. But detectives aren't as lucky with Zodiac. Most of his murders involved him shooting the victim and running away. The only crime scene where he had extended contact with his victims was at Lake Berryessa. There, he stabbed Bryan Hartnell and Cecelia Shepard repeatedly before returning to his vehicle and driving away. Today, there's a possibility forensic techniques could yield genetic material from the killer, but in 1969 that technology was decades away.

The only possible DNA sample comes from beneath a stamp stuck to one of his infamous letters. The sample, developed in 2002 by San Francisco police, is only a partial profile. Because it's not someone's full DNA profile, it can't be used to point to just one person. It can only rule someone in as a possibility or exclude them if it isn't a match. It's also entirely possible the sample doesn't belong to Zodiac at all; it could be from a mail worker or any number of people who handled the letter over the years.

Without all the modern crime-solving strategies we're used to — CCTV, touch DNA, cellphone data, etc. — investigators are left with almost nothing to work with. On that note ...

The sketch is close to useless

Although ubiquitous, the only police sketches released of the Zodiac Killer are next to worthless. There's a reason dozens of people over the decades have said their neighbor/father/real estate agent matches the sketch. It's so nondescript, it could be countless young-to-middle-aged white men in the 1960s. Take away the distinctive glasses and it's even less informative.

Its accuracy also is far from concrete. Although Zodiac left two survivors, Hartnell and Michael Mageau, neither man got a good look at the killer's face (he wore a mask at Lake Berryessa and he shone a flashlight in Mageau's eyes). The only people who unquestionably saw his face were three teenagers on the night of Oct. 11, 1969.

The teens were home at Washington and Cherry in Presidio Heights when they saw a man assaulting a taxi driver parked outside. They glimpsed the man rummaging around the cab for less than a minute, at a distance of some 50 feet, illuminated only intermittently when his face caught the streetlight.

The only other visual came from a police officer that night, who thought he glimpsed a man who could be Zodiac walking from the crime scene. The encounter lasted seconds in the dark — not to mention the man could easily have been an ordinary passerby — and the officer never made his own sketch. He was shown the teens' sketch and offered some feedback.

Not to mention, even in the best of circumstances, sketches done from memory aren't terribly reliable.

The letters simultaneously provide too much and too little information

For the legion of Zodiac Killer hunters around the world, it seems like his many taunting letters must surely provide a clue to his identity. But they're a rabbit hole by design.

Many details are plagiarized or paraphrased from other media, like short stories, movies and operas, providing little more than a window into Zodiac's pop culture preferences. The 1932 movie "The Most Dangerous Game," for instance, is referenced in one letter. The creepy claims of creating an army of slaves in the afterlife are Zodiac's attempt at myth-building, crafting himself into a dime-novel villain.

The rest is your run-of-the-mill bragging. Although all these clues can hint at someone's personality, they're unlikely to have some kind of hidden meaning that, when magically uncovered, will lead to a breakthrough in the case. And unlike the manifesto of Unabomber Ted Kaczynski, which was recognized by his brother, if no one's recognized Zodiac's writings by now, it's probably because it is intentionally different from his everyday correspondence.

The letters could have possibly provided a clue into where Zodiac bought his stationery or mailed his letters, but those leads have all resulted in dead ends.

Zodiac knew when to stop

Some believe Zodiac continued committing crimes after the murder of cab driver Paul Stine, but Stine's is the last murder that can be definitively attributed to the elusive killer. It is perhaps not a coincidence this was Zodiac's closest call. He was seen by three people and was mere moments from being caught by the police. The near-miss might have frightened him.

In any case, he'd already gotten what he wanted: infamy. Unlike killers like Jeffrey Dahmer or Ted Bundy, Zodiac didn't appear to be obsessed with killing. He was obsessed with fame. In a few short months, he became the world's most talked-about serial killer, and the thing that really did it were his weird, cryptic letters. Although the murders stopped, the letters did not, suggesting he continued to find his high from publicity rather than death.

Although it's commonly believed multiple murderers only stop when they're caught or die, that's simply not true. Killers like Joseph DeAngelo and Dennis Rader, aka BTK, stopped, while Gary Ridgway temporarily stopped when he got married. It's not unknown for serial killers to pause when their personal lives change, whether from the birth of a child or a change in work schedule that curtails their hunting hours.

Although it's more terrifying to believe a killer could simply slip back into society, an ordinary person like your friend or neighbor, it has happened. And it's possible that's exactly what Zodiac did, evading the era of DNA and surveillance technology that would have undoubtedly nabbed him had he continued.

(c)2021 SFGate, San Francisco

McClatchy-Tribune News Service

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