In the fall of 1969, seven-year-old David asked his father why police cars had been following his school bus every day for a couple of weeks. “Oh yeah,” his dad responded matter-of-factly. “There’s a serial killer who has killed four or five people, who calls himself Zodiac, who’s threatened to take a high-powered rifle and shoot out the tires of a school bus, and then shoot the children as they come off the bus.”

A few decades later, still haunted by his childhood bogeyman, David directed a movie about the years-long effort to find the Zodiac. It made considerably less money than most of his other films, like Fight Club or The Girl with the Dragon Tattoo, perhaps because it’s 157 minutes long, and in the end, the killer is never captured.

Like David Fincher, our culture can’t seem to get over the Zodiac killer. He shows up in Dirty Harry, The Exorcist III and the seventh season of American Horror Story where he’s played by Lena Dunham. He’s the subject of his own subreddit and several internet forums — Zodiac Killer Site, Zodiac Revisited, Zodiac Ciphers, Zodiac Killer Mystery, Zodiac Killer Facts and Zodiac Killer Hoax. Thanks to a surprisingly robust meme, a May 2016 poll found that 5 percent of Americans believed Ted Cruz was the Zodiac killer and another 18 percent were unsure. Cruz himself has, as academics like to say, made his own contribution to the discourse.

Our collective obsession with the Zodiac killer is frankly disproportionate to the crimes he may have committed. He killed, by most estimates, five people, less than one-tenth the number of people Stephen Paddock shot to death last year at a Las Vegas music festival. But who do you think will be remembered a century from now? Close your eyes and you can see the cryptograms; the circle overlaid with a cross.

Like Jack the Ripper, the Zodiac has become more myth than historical fact. And a few amateur sleuths, chief among them a semi-retired community college writing professor in St. Louis, think the Zodiac was never anything other than a myth — that there was no single Zodiac killer, and that the infamous Zodiac letters were a hoax.

First, though, some basic facts about the five “canonical” Zodiac murders.

On December 20, 1968, teenagers Betty Lou Jensen and David Faraday were parked in a gravel turnout on Lake Herman Road, near the town of Benicia in Solano County, California. Another car pulled in beside them, and the driver exited his vehicle and (likely) ordered the teenagers to come out. He then shot and killed them both, Faraday as he was still getting out of the car and Jensen as she was running away.

Four miles away (Blue Rock Springs Park in Vallejo) and six months later (July 4, 1969), Darlene Ferrin and Michael Mageau were sitting in Ferrin’s car when another car came up and parked behind them. The driver emerged with a flashlight, and Ferrin and Mageau assumed he was an undercover cop. Mageau, who was sitting in the passenger seat, rolled down his window, and the stranger shone his flashlight in their faces and immediately began shooting them, killing Ferrin and severely wounding Mageau.

September 27, Lake Berryessa in Napa County: Bryan Hartnell and Cecelia Shepard were having a picnic when a man approached them dressed like this, holding a gun. The man told them he was an escaped convict and needed their money and their car so he could get to Mexico. They quickly agreed. The stranger made Shepard tie up Hartnell with some clothesline and then he tied up Shepard as well and made them both lie face-down on the ground. And then, to their shock, he started stabbing them with a knife. Again, the woman died and the man barely lived.

One more, this time in San Francisco, October 11, 1969, Presidio Heights. Cab driver Paul Stine stopped along Washington Street near the corner with Cherry to let out his passenger, only to have the passenger shoot him in the back of the head. Three teenagers saw the shooter search Stine’s pockets, wipe down the car inside and out, and then walk away toward the park.

If these were all the facts you had, you wouldn’t guess these killings were the work of a single man. None of the fingerprints found at the crime scenes matched, nor did any of the ammo. Each murder had a different M.O.: making the victims get out and then shooting them; going to the car and shooting them while they were inside; donning a bizarre outfit, talking to the victims for several minutes, tying them up and then stabbing them; shooting a cab driver from behind.

Four letters, one phone call, a note written on a car door: These are the main pieces of evidence linking these disparate crimes to a single killer. Thomas Henry Horan, however, finds the evidence unconvincing.

Horan is semi-retired now, but he’s taught at various community colleges in the St. Louis area over the years. His pedagogical focus is teaching writing “across the curriculum,” and he’s especially interested in teaching students how to apply their skills as readers to their writing, which he calls the “ultimate act of reading.” He also likes to play detective, because before he started teaching he was a detective, first in the insurance industry and then for a private agency. So it was natural that he was drawn to the Zodiac. “I was intrigued,” he says, “by how successful he had become as a writer,” and how the Zodiac’s writing was shaped by the newspaper articles he was reading.

We wouldn’t remember the Zodiac, nor even know the Zodiac’s name, if it weren’t for the 20 or so letters he wrote, mainly to the San Francisco Chronicle. This is where we get the cryptograms, the circle-and-cross logo, the tagline (“This is the Zodiac speaking”). Horan became fascinated by these letters. But he also became fascinated by something else: the original Zodiac case files.

The Zodiac murders were investigated by four local police departments (Solano County, Vallejo, Napa County and San Francisco) and the California Department of Justice, and for several years, the only civilian who’d gotten access to all their files was Robert Graysmith, or Jake Gyllenhaal’s character in Fincher’s movie. Graysmith quoted at length from these case files in his 1986 book Zodiac, and the amateur sleuths who followed him had little choice but to depend on his presentation of the facts. But then Zodiac obsessive Mike Rodelli found out the FBI had received copies of all the Zodiac case files from the relevant police departments, and after years of legal wrangling, he obtained copies of nearly all of them, some 2,500 pages, through the Freedom of Information Act. By 2010 they were all online: an armchair detective’s dream.

As such, Horan read every single page of the case files, something very few if any have done since Graysmith. He came to believe that whoever wrote the Zodiac letters had also read many of these reports, and indeed knew things from these reports, some of them wrong things, which the killer couldn’t have known.

The Zodiac’s first letter (well, actually, first three letters, because he sent nearly identical letters to the Chronicle, Examiner and the Times-Herald) came nearly four weeks after the July 4, 1969, shooting at Blue Rock Springs Park. Zodiac took credit for the shooting as well as the double murder on nearby Lake Herman Road the previous December. “To prove I killed them,” he wrote, “I shall state some facts which only I + the police know.”

Most of these facts were indeed things which only the killer and the police could have known. Except Horan would argue “the police” was a pretty large number of people, and in practice included several news reporters. Police reports were shared with reporters, who used them to write up their stories on the latest horrid crime; in fact, reporters would often help police officers out by typing their reports for them.

The real tell, according to Horan, is what the Zodiac got wrong. Darlene Ferrin wasn’t wearing patterned slacks, or as the Zodiac wrote in the other two letters, “patterned pants.” Here’s what she was wearing:

So in addition to shoes and a bra and panties, she was wearing a “blue and white flowered slack dress.” What was a slack dress? I tried to Google this but kept getting hits for dress slacks, so I asked my mom, who would’ve been just a touch younger than Ferrin in 1969 and mostly grew up in Southern California. She told me a slack dress was sorta like a jumpsuit, flared at the bottom, like this:

I asked my mom how likely it would be that a guy would mistake this for pants, and she said not very. “They were so wide at the bottom, almost like bell-bottoms, that most of the time it just looked like you were wearing a dress.”

This is clearly ironclad proof y’all.

For real, though, what’s more plausible: that the killer, as he was holding a flashlight on Ferrin for a few seconds and shooting her while she was seated, saw her wearing something like the above and processed it as “patterned slacks”? Or that he read “slack dress” in the police report, was a middle-aged dude and didn’t know exactly what it was, and thought it was slacks? And keep in mind that anyone looking at a carbon copy of the police report would’ve read this…

…as “Blxxxxxxxxered slack dress.” Something something, some sort of pattern?

On August 4th, the Examiner received another Zodiac letter in which he claimed, among other things, that he didn’t leave Blue Rock Springs Park “with squealling tires + raceing engine,” but instead “drove away quite slowly.”

This was contrary to what the surviving victim told the police.

As well as another witness who heard the car “take off at super speed,” burning rubber and “squealing its tires.”

There was, however, someone who was driving slowly out of the park and was stopped by the police, only to be eventually let go.

Horan believes the Zodiac was trying to undercut Michael Mageau’s and George Bryant’s testimonies (note the Zodiac’s and Bryant’s shared reference to squealing tires) and instead point the police toward this Andrew character — someone who was never discussed in the press and whom the actual killer, who drove off more than 15 minutes before the police arrived, couldn’t have known about.

The only other evidence tying the Lake Herman Road and Blue Rock Springs Rock shootings to the same killer was a phone call reportedly made to the Vallejo Police Department the night Mageau and Ferrin were shot.

Horan points out a few things about this call. It was made a full 30 minutes after the shooting was reported to the police. Anyone listening to the police radio frequency — back then he wouldn’t have even needed a police scanner — would have quickly learned there were two victims in a brown car, and that the police should be on the lookout for someone with a 9-millimeter Luger.

Furthermore, Blue Rock Springs Park wasn’t a mile east of the police station, it was two miles north of the police station and then some. The park was, however, a mile east of the fire station, and someone listening to the police radio would’ve heard a call for an ambulance, telling them to head a mile east on Columbus Parkway.

Was this a prank call? Maybe. Did the Vallejo police embellish the call to link it to the Lake Herman Road murders? Well, it’s worth noting that the July 5th article on the Blue Rock Springs Park shooting in the Times-Herald, which relied on the initial police reporting — days before the call was transcribed as above — mentioned a mysterious caller but nothing about him claiming to have “killed those kids last year.” This was particularly odd since the article did in fact discuss the Lake Herman Road incident.

Horan claims to have spoken with several retired cops from the North Bay area and learned that the sites of the December 20th and July 4th murders weren’t, as they’re often portrayed, merely lovers’ lanes; they were where kids went to buy drugs. Vallejo was a major center of the burgeoning meth trade, under the aegis of the Hell’s Angels. Michael Mageau was wearing three pairs of pants and three sweaters simultaneously, on the Fourth of July — something that might make sense if, you know, were planning on breaking into people’s houses and shedding one outfit after another so you didn’t fit a police description.

Was this a drug deal gone bad? Was a crooked cop somehow involved? The speculations can get downright wild, but it’s conceivable why it might be convenient to pin these murders to a deranged serial killer. Indeed, the police had good suspects in each of the canonical Zodiac killings, but they were all eventually ruled out because none of them could have committed any of the other crimes. A serial-killer hypothesis can act as an alibi-machine.

The Lake Berryessa incident is the most lurid of all the Zodiac killings, with the executioner’s hood, the elaborate backstory, the tying up, the stabbing. Yet not a single of the Zodiac letters ever referred to it. The call made to the police, presumably by the killer, made no reference to the Zodiac or the killings on Lake Herman Road and at Blue Rock Springs Park.

The killer did wear the weird bib with the Zodiac symbol on it, but that had already been in the papers for several weeks, enough for a copycat to put something together. Then the killer, or someone, wrote this note on Bryan Hartnell’s car, grouping his act with the two previous canonical Zodiac killings.

Is this the same handwriting as in the Zodiac letters? Zodiac enthusiasts disagree mightily. What about the j? Shouldn’t it be squiggly?

I’d also like to point out the double-L in “Vallejo” is much more spread out on the car door than in the Zodiac letters. But at least one person on the Zodiac Killer Site forum thinks this is all bullshit: “Compare the three E’s, and four 6’s on the car door to one another.”

If we’re gonna quibble over the squiggle in a j, then “we could argue there were different writers, who contributed to the four 6’s on the car door.” Also, are we supposed to believe the killer tried to copycat the Zodiac letters’ handwriting — that’s a tedious task to undertake when you’re fleeing your own crime scene! And maybe someone’s handwriting is different when they’re bending down and writing on a car door.

That still leaves the question, though, of why none of the Zodiac letters ever mentioned Lake Berryessa. As the 1970s wore on, the Zodiac became increasingly full of shit and claimed to have committed all sorts of murders, obviously relying on what was reported in the newspapers — why did he never take credit for something widely attributed to him?

The murder of Paul Stine seems at first glance the least likely to be connected to the other murders. The previous targets were all young couples in the North Bay area; Stine was a cab driver in San Francisco. The shooter stole Stine’s wallet and even the cash lying around that Stine had made in cab fare that day. The police had what they thought was an obvious suspect, someone whose M.O. was to make a cab driver drive him somewhere in Presidio Heights, and then, once the car was stopped, rob the driver at gunpoint. Perhaps this time the gun accidentally went off. The first SFPD bulletin for Stine’s shooter, debuting the famous composite sketch now entrenched in Zodiac lore, said the man was “wanted for murder and robberies of cab drivers.”

But if Stine’s shooter wasn’t the Zodiac, how did he manage to include bloody pieces of Stine’s shirt in three subsequent letters? Here’s Horan’s explanation, and this is where he loses a lot of people. The three pieces were each ripped from the back of Stine’s shirt.

As you can see, Stine mostly bled out his nose. A pool of blood would have collected to his right on the seat. Several minutes after the police arrived, Stine’s body was turned around so that his back was lying in that pool of blood. It was at this point that the back of Stine’s shirt got bloody — and it’s a different sort of bloody because it was semi-coagulated. You can see in this picture, after Stine’s body had been shifted around, that there was little to no blood on the back of the seat where he was originally sitting.

You can sorta see, though, where the pool of blood was collecting down to what was originally his right. You can see it better here, smeared from when he was lying in it:

Why does this matter? Because the pieces of shirt mailed to the Chronicle and the lawyer Melvin Belli had that same semi-coagulated blood on them.

In other words, according to Horan, these pieces of shirt must have been ripped off after Stine’s body was moved, long after the shooter had fled. Perhaps the shooter did rip off a piece of the shirt for wiping up blood, and then during the couple of hours when the cab was sitting in a public parking garage and Stine’s shirt was hanging up to dry, someone sneaked by and surreptitiously ripped off a few more smaller pieces in the same spot.

The Chronicle received a Zodiac letter on October 13, 1969, which contained a piece of Stine’s shirt and took credit for the deaths of Stine and “the people in the north bay area.” Zodiac also threatened to “wipe out a school bus,” suggesting he could “shoot out the front tire + then pick off the kiddies as they come bouncing out.”

It was at this point that the Zodiac became a national story.

Who does Horan think wrote the letters? He believes there were two writers — that the handwriting and personality change after Stine’s death. He suspects most of the letters, including the ones with the pieces of Stine’s shirt, were written by none other than Graysmith, who was far more than the cartoonist at the Chronicle — he was on the production team. It would’ve been Graysmith’s job to make maps, photograph comic strips and ads for the newspaper, and indeed to photograph the Zodiac letters. As for the initial letters, the ones tying together the Lake Herman Road and Blue Rock Springs Park murders, Horan’s pet suspect is a Napa County deputy who created the county forensics department, was an expert in forgery and had worked for several newspapers in the past. Horan has a sample of his handwriting.

The top image in each of the groups below comes from the above writing sample; the others come from Zodiac letters.

Are you convinced yet?

Well, most folks on the Zodiac forums are not. They liken Horan to a creationist, a flat-earther, a circus barker, “a gossip yakking over the backyard fence.” Horan, who frequently calls his chief critics “liars” and “double-crossers,” doesn’t make it any easier for them to like him. Horan says they don’t care about the victims, they only care about the killer; that for them, finding out there’s no Zodiac would be like finding out there’s no Santa Claus.

But I mean, is he wrong? Of course it’s the killer we care about. The dudes hashing out their theories on forums for years on end, spending their own money on FOIA requests and handwriting analyses, trash-talking each other on true crime podcasts — they’re not doing this because they care passionately about finding justice for Betty Lou Jensen.

Here’s a confession. I first heard Horan’s theory on a podcast a couple of years ago and found it utterly compelling. And as I researched this piece, I was thrilled by every piece of evidence that seemed to confirm the hoax story — The slack dress! One mile east! The un-squiggled j! But I was equally disappointed by any evidence, or any little thought crossing my mind, that pointed the other direction. Maybe when the Stine letter refers to having killed the people in the North Bay area, he’s including the Lake Berryessa incident. Maybe he claimed to have driven away slowly out of Blue Rock Springs Park because, I don’t know, he wanted to fuck with the press, or maybe Mageau and Bryant misremembered what they heard and he really did drive slowly, and maybe it’s just a coincidence the police briefly stopped someone else going slowly, and Zodiac knew nothing about it. Maybe the Zodiac thought a slack dress was called slacks — hell, maybe he thought she was wearing separate pants. It was dark and things were happening fast.

But just like Horan’s critics want there to be a Zodiac killer, I want there to be a Zodiac hoaxer. They fantasize about getting away with the perfect crime, and I fantasize about getting away with the perfect lie. That’s a normal fantasy, I think, for a writer to have.

In one of the earlier drafts of the Zodiac script, there was a scene where Robert Graysmith and detective Dave Toschi watch the climax of Dirty Harry. After spending the whole film hunting down the Scorpio Killer, Clint Eastwood finally has him cornered on a rooftop. Eastwood utters his famous soliloquy: “Maybe I fired five bullets, maybe I fired six. In all the confusion, I lost count. So the only question is, do you feel lucky? Do you, punk?” Scorpio reaches for his own gun and Clint Eastwood “blows his head off.” The audience cheers. Then, to the eventual confusion of their fellow audience members, Graysmith and Toschi look at each other and “burst out hysterically laughing.”

It’s always “disappointing,” Horan told me, when a serial killer gets caught, because he seldom lives up to what people had imagined. What Jack the Ripper and the Zodiac share in common, and why they’ll still be famous a century from now, is that they were never caught. They can be whoever we want them to be: Someone with supernatural control over women and weak men, someone who can make himself seen when he wants to be seen and then just as easily disappear, someone who can make a whole country afraid.

Most of us will outlive the Zodiac, the killer or the hoaxer, if indeed he isn’t already dead. But in another sense, he can’t die, and there’s something in us that wants it to stay that way. That’s why we’ve dubbed Ted Cruz the Zodiac even though he was born in 1970 after all of the canonical murders, as if it’s like being the Dalai Lama and can transmigrate from soul to soul. Maybe we secretly believe that if the Zodiac can never die, then neither can we.