The Dexter Killer Mark Twitchell lured men to his ‘kill room’ by posing as a woman online

Mugshot of Mark Twitchell
Mark Twitchell is a cold-blooded killer who was compared to the fictional serial killer Dexter Morgan. Pic credit: @CBS Mornings/YouTube

Mark Twitchell, aka The Dexter Killer, lured and brutally murdered Johnny Altinger at his garage in Edmonton, Canada, in 2008. The twisted murderer had meticulously planned the killing and had even prepared a “kill room” for his victim.

Only seven days previously, The Dexter Killer had attempted to murder Gilles Tetreault, but fortunately, Tereault managed to fight off his attacker and escape.

On the surface, Mark Twitchell seemed like an ordinary average guy. The movie maker was a husband and a father, and he was affable, relatively handsome, intelligent, and charming. He had high hopes of making it big in Hollywood, but terrifyingly, he was also a stone-cold ruthless killer.

Twitchell had a disturbing dark side and a fascination with the fictional serial killer Dexter Morgan. The show Dexter featured a Miami PD forensic technician who led a secret life as a vigilante serial killer, killing bad guys.

Canadian Twitchell would later show he had an obsession with Dexter that manifested itself in one attempted murder and one actual murder. However, one big difference between Dexter and Twitchell was the real-life murderer targeted innocent people.

The killer chose his victims by pretending to be a woman on the dating app Plenty of Fish. Twitchell’s two victims were then lured to his garage, where instead of being met by a single woman, they were brutally attacked by The Dexter killer.

Mark Twitchell: Dexter killer murdered Johnny Altinger

On October 10, 2008, 38-year-old Johnny Altinger set out on a date. He followed the very precise directions he had been given by his supposed female date. His so-called date had not given him an exact address but had given him step-by-step instructions to a garage door.

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The cops later concluded that Twitchell attacked the unsuspecting Altinger as he arrived and duct-taped him to a chair before brutally beating and stabbing him to death. The killer then dismembered the body and dumped the remains down a maintenance hole into a sewer.

Three days after Altinger’s murder, Twicthell sent an email to his victim’s friends and family, pretending to be his victim. The email claimed that Altinger had met a woman called Jen, and the pair had gone off on an impromptu romantic trip to Costa Rica. He also supposedly emailed his boss to quit his job.

Altinger’s friends were suspicious of the email as it didn’t really sound like him. One friend said Altinger would always include emojis, jokes, and wisecracks in his emails to her, but these were missing from this message.

The cops later learned that Twitchell had used Altinger’s keys to break into his apartment and use his computer. He had also updated Altinger’s status on MSN messenger. Chillingly, it now read, “I’ve got a one-way ticket to heaven and I’m not coming back.”

Email sent by Twitchell to Altinger's friends
Mark Twitchell sent this email to Johnny Altinger’s friends. Pic credit: Edmonton Crown Prosecution Office

Altinger’s friends also found their way into his apartment, and they became even more concerned when they found no evidence that he had prepared for a trip abroad.

Luckily, a friend remembered that Altinger had emailed them the set of directions he’d been given for his date a few days beforehand. When the Edmonton police followed the directions, they found Twitchell’s “kill room.”

The police would later say that Altinger’s actions in sending the directions to a friend ultimately saved the lives of others. Detective Mark Anstey said Altinger was “in a roundabout way, was a hero” and that “he definitely saved a lot of grief for other families.”

The cops found a room that was covered in plastic sheeting, had a table that was for dismembering bodies, and a “tool kit “processing kit” containing butcher’s knives and a serrated saw. There was also blood splattered on the floor. It looked very similar to a scene from Dexter.

Twitchell told the cops not to worry; he said he was filming a movie called House of Cards that featured a serial killer luring men to a garage where they would be killed.

The cops searched Twitchell’s house, car, and belongings, and they got a breakthrough. They found a knife with Altinger’s blood and discovered his blood in the trunk of the car. It was enough to charge Twicthell with first-degree murder.

The Dexter Killer had attempted to murder Gilles Tetreault

At this point, Gilles Tetreault came forward to tell police that he had nearly been the first victim. On October 3, Tetreault had followed similar directions to Twitchell’s garage after meeting a woman called Sheena on Plenty of Fish.

He had followed the directions precisely and went through the slightly opened garage door when he was grabbed by Twitchell and shocked with a stun gun. The killer wore a hockey mask as he pointed a gun at Tetreault and ordered him to the ground. Twitchell then put some duct tape over his victim’s eyes.

Tetreault decided he had to fight back. He ripped off the duct tape and threw himself at the gun. Luckily, the gun was a fake, and the pair became locked in a violent struggle, eventually leading to Tetreault breaking free and fleeing the garage.

A copy of the directions to the Dexter killer's garage
Mark Twitchell sent these directions to Gilles Tetreault. Pic credit: Edmonton Crown Prosecution Office

Tetreault later admitted feeling embarrassed about being fooled by Twitchell and decided not to go to the police. He came forward after learning about Altinger’s death.

Mark Twitchell still denies murder, claims he was making a movie

Twitchell was eventually found guilty of first-degree murder and was sentenced to 25 years. However, he still claims he is innocent. The killer even admitted to luring men to his garage but insisted it was all a promo stunt to drum up publicity for his movie.

He said he planned to trick men into coming but would allow them to escape so that when the film came out, they would come forward claiming that that had happened to them, thereby creating a buzz about the film.

As it happened, Twitchell was actually making a movie, and he had even shot footage with real actors, some of whom were interviewed during the investigation. But nobody really believed Twitchell’s claims that he is anything other than a cold-hearted murderer.

While searching his laptop, the cops found a document called the SK Confessions, which described his sick crimes. He claimed it was a screenplay, but it came far too close to the truth.

Mark Twitchell: Killer was a big Dexter fan

Twitchell has found himself compared to the character from Dexter for a few reasons. Apart from the similarity of his kill room to Dexter Morgan’s, Twitchell admitted to being a big fan of the Showtime show. His profile picture on Facebook was him posing as Dexter.

During his time in prison, the killer acquired a TV set for his cell and admitted to catching up on his favorite show. When discussing the SK Confessions document, Twitchell claimed that he didn’t “copy-cat” Dexter but admitted he wanted to pay “homage” to the character.

Investigative journalist Steve Lillebuen corresponded with Twitchell while writing his book, The Devil’s Cinema: The Untold Story Behind Mark Twitchell’s Kill Room. Lillebuen said Twitchell contacted him after the killer learned the journalist was writing a book about him.

In the end, Lillebuen said he received 350 pages worth of letters from the murderer, which helped give some insight into the twisted killer’s mind. Twitchell did not openly confess, but he did write, “It is what it is and I am what I am.”

The killer, who had had a normal upbringing and life until he decided to murder, also claimed that there had been no traumatic events in his life that might have turned him into a murderer. He wrote to Lillebuen, “It would appear that I am unique in the world. There is no key. No root cause.”

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