5 Chilling details about Mark Twitchell's crimes 

Mark Twitchell, infamously known as the "Dexter Killer" was the subject of the 48 Hours episode on ID that re-aired on August 17, 2024. The former Canadian filmmaker is currently serving a life sentence in prison following the murder of a 38-year-old tech enthusiast from Edmonton, Canada.

The episode, titled The Dexter Killer of 48 Hours on Investigation Discovery, shed light on the strange television-inspired murderer. The synopsis of the episode as per Investigation Discovery reads:

"Just over a decade after Mark Twitchell was convicted of murdering Johnny Altinger, who prosecutors say he lured into a garage, stabbed and dismembered, Troy Roberts takes a rare look inside Twitchell's mind through his writings."

Mark Twitchell has been named "the Dexter Killer" owing to his fascination with the Showtime drama Dexter, which follows a serial killer named Dexter Morgan (played by Michael C. Hall). Twictchell's fascination with the series led him to mimic the fictional character, leading to the gruesome murder of Johnny Altinger. Here is a look at some of the most chilling details about Twitchell's crimes.

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Looking at 5 chilling facts about Mark Twitchell's crimes

1) Mark Twitchell posed as a woman on dating sites to lure his victims

A still of Twitchell (Image via CBS)

Mark Twitchell was a married Canadian film director and even had a kid. However, he impersonated women on dating sites to lure victims in his rented garage, to play out his murder scenarios. He lured his victim, a 38-year-old named Johhny Altinger, in 2008. He stabbed Altinger to death, dismembered his body, and dumped them in a storm drain.

Altinger was Twitchell's first murder victim but he had earlier lured another person named Gilles Tetreault, who escaped. The victim later spoke up, following Altinger's murder and Twitchell's arrest.

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2) Twitchell was inspired by the Showtime series Dexter

Mark Twitchell was heavily inspired by the Showtime series Dexter, where the protagonist was an avenging serial killer who used to dismember his victims in a controlled environment. Twitchell mimicked Dexter's style of murder and even posed as the character on his Facebook profile.

According to police, Twitchell's garage looked like something from the series. Plastic sheets covered every window in the garage and bloodstained tablecloths and cleaning materials were all spread out.

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3) Twitchell filmed a movie with the same premise as the act of his murder

Twitchell was filming a short film titled House of Cards, the premise of which followed a man luring other men on the internet to a garage and killing them, disguised using a hockey mask.

Twitchell followed the exact pattern as described in the plot of his short film, which was one of the most prominent circumstantial evidence linking him to Johnny Altinger's murder.

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4) Twitchell sent fake e-mails from Johnny Altinger's ID after murdering him

Twitchell sent fake emails to make people believe Johnny was still alive (image via Pexels/Luis Quintero)

The search for Johnny Altinger was spurred by his friends when they were suspicious about certain emails received from his email ID. It was later discovered that it was Mark Twitchell who broke into Altinger's house and sent emails from his ID to his friends.

Altinger's friends were suspicious when they received emails saying that Altinger was on an extended vacation with his date (the fake date set up by Twitchell). Twitchell did not reply to a request for a forwarding address for Altinger's last payment, even though he submitted an email of resignation to Altinger's workplace.

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5) Twitchell documented his descent into becoming a killer

The most incriminating evidence that confirmed Twitchell as Altinger's murderer was a deleted folder from his computer titled "SK Confessions." The folder (serial killer confessions) contained detailed accounts by Twitchell where he explained how he set up his kill room and even detailed the failed attempt to murder Gilles Tetreault.

In the documents, Twitchell wrote:

"This is the story of my progression into becoming a serial killer"

The documents also contained detailed self-analyses by Twitchell.

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Although Twitchell argued his innocence in the court, claiming he stabbed Altinger to defend himself, he was convicted of first-degree murder in 2011 with the option of parole after 25 years. Shockingly, Mark continues to watch Dexter in his prison cell.