Mark Twitchell

Early life and filmmaking career

Mark Andrew Twitchell was born on July 4, 1979, in Edmonton, Alberta. He dreamed of making blockbuster films and pursued this ambition by graduating from the Radio and Television Arts program at the Northern Alberta Institute of Technology in 2000. His personal life involved two marriages during this period. He married his first wife, American Megan Casterella, in January 2001, but the couple divorced in 2005 due to irreconcilable differences. In January 2007, Twitchell married his second wife, Jess, a marriage that would end following his arrest with the divorce finalized in 2010. Through his company Xpress Entertainment, Twitchell directed a notable project in 2007, a full-length Star Wars fan film prequel titled Star Wars: Secrets of the Rebellion. The film, set just before the events of Star Wars: Episode IV, A New Hope, included a cameo appearance by British actor Jeremy Bulloch, famous for playing bounty hunter Boba Fett. Despite this professional connection, the film remained in post-production and was never publicly released. Twitchell also wrote a script for a buddy comedy called Day Players. In September 2008, he shot a short horror film entitled House of Cards at a residential garage he rented in south Edmonton, a location he advertised as a film studio.

The murder of Johnny Altinger

In October 2008, John Brian Altinger, a 38-year-old quality control inspector originally from White Rock, British Columbia, was living and working in Edmonton. Unknowingly, he began interacting on the dating website Plenty of Fish with a profile operated by Mark Twitchell, who was posing as a woman. Twitchell's intent was to lure victims to his rented garage under the guise of a date in order to kill them. On October 10, 2008, Altinger informed his friends of his plans to meet this woman and sent them the address Twitchell had provided. Upon Altinger's arrival at the garage, Twitchell attacked him, bludgeoning and stabbing him to death. Twitchell's subsequent attempts to dispose of the body were methodical and gruesome. He first tried to burn the body but was unsuccessful. He then proceeded to dismember Altinger's remains, cutting them into pieces. He placed the dismembered remains into garbage bags and dumped them into a storm sewer located south of 130th Avenue and 87th Street in Edmonton.

To create a cover story and delay the discovery of his crime, Twitchell engaged in an elaborate deception. He broke into Altinger's condominium and used his computer to send emails to Altinger's friends. These emails claimed that Altinger had met a woman who spontaneously took him on an extended vacation to Costa Rica. Twitchell also sent a resignation email to Altinger's workplace, Argus Machine Co. Ltd. However, he did not respond to a subsequent request from the company for a forwarding address to send Altinger's final paycheque. Altinger's friends grew suspicious because the emails did not match his character, and they found his passport still at home alongside dirty dishes, with no signs of packing for a trip. Their concerns led them to break into his condo themselves, after which they contacted police, prompting the Edmonton Police Service to launch a homicide investigation.

Investigation, arrest, and key evidence

The Edmonton Police Service investigation initially led them to Twitchell after he provided an account of knowing Altinger. Twitchell claimed he had met Altinger by chance, and that Altinger was leaving for Costa Rica with a wealthy woman and sold his Mazda 6 to Twitchell for the forty dollars in cash he had on hand. Police found this story highly improbable. They impounded both Twitchell's laptop and his car, a Mazda 6. Forensic analysis of the vehicle revealed the presence of John Altinger's blood in the car's trunk, providing direct physical evidence linking Twitchell to the crime. The digital evidence proved even more damning. From Twitchell's laptop, police recovered a deleted document titled 'SKConfessions', an acronym for 'Serial Killer Confessions'. The document's opening passage stated, 'This story is based on true events. The names and events were altered slightly to protect the guilty. This is the story of my progression into becoming a serial killer.' It provided a detailed narrative of planning, a failed first attempt to lure and kill a man, and a successful second attempt that closely mirrored the facts of Altinger's murder, including the use of fake online dating profiles, the garage location, and the dismemberment and disposal of the body. Based on this overwhelming evidence, Mark Twitchell was arrested on October 31, 2008, and charged with the first-degree murder of Johnny Altinger.

Trial, conviction, and sentencing

Twitchell's first-degree murder trial was preceded by significant legal arguments over media access. Crown prosecutors and the defence sought extensive publication bans and sealing orders on police evidence to protect Twitchell's right to a fair trial. The judge agreed, stating pretrial publicity posed a real risk, though the jury pool was later polled to gauge any prior media influence. Once the bans were lifted, the trial attracted a large media presence, including crews from American programs like Dateline NBC and 48 Hours. The Crown's case hinged on the 'SKConfessions' document, presenting it as a factual blueprint for the murder. Twitchell took the stand and admitted to killing Altinger and authoring the document. However, he claimed he acted in self-defence during a confrontation. He described the document as 'fiction based on fact', a creative writing exercise designed to make a compelling story by pretending he had planned the death deliberately. The trial repeatedly highlighted Twitchell's interest in the television series Dexter, and his identification with its protagonist, vigilante serial killer Dexter Morgan, solidified his 'Dexter Killer' nickname in media reports. On April 12, 2011, the jury found Mark Twitchell guilty of first-degree murder. He received the mandatory sentence of life imprisonment with no possibility of parole for 25 years. Twitchell later filed an appeal notice arguing the sensationalized media coverage prejudiced the jury, but he abandoned this appeal in 2012.

The attempted murder of Gilles Tetreault and severed charges

Before murdering Johnny Altinger, Mark Twitchell had lured another man, Gilles Tetreault, to the same garage. Tetreault, a computer company contractor, testified that he was expecting a date with a woman named Sheena from Plenty of Fish. When he arrived, he was attacked by a man wearing a hockey mask and wielding a stun baton. A violent struggle ensued, during which Tetreault managed to fight off his assailant and escape. He did not report the attack to police at the time, later stating he was too embarrassed. Tetreault came forward after learning of Twitchell's arrest and was nicknamed 'The One Who Got Away' by media. Following Twitchell's murder conviction, Crown prosecutors considered pursuing the attempted murder charge against him for the attack on Tetreault. Detectives believed they had ample evidence, and Twitchell himself had admitted to the attack on the witness stand. The Crown had initially argued to try the murder and attempted murder charges together, contending they were part of the same 'transaction' of Twitchell's attempt to become a serial killer. However, Court of Queen's Bench Justice Terry Clackson ruled against this. In his decision, Justice Clackson wrote that while the offences were related, they remained 'discrete' and were different transactions under Canadian law. He ordered the charges to be severed. On June 17, 2011, the attempted murder charge was formally stayed, meaning the Crown could resurrect it within one year. As Twitchell was already serving a life sentence with maximum parole ineligibility, there was no legal need to proceed further, and the charge was eventually dropped.

Media coverage and cultural impact

The Twitchell case generated extensive and often sensational media coverage, creating debate about the ethics of reporting such graphic details. After the trial, the case continued to be a subject of public fascination. In December 2012, actor Michael C. Hall, who portrayed Dexter Morgan, was asked about the case during an interview on the CBC radio show Q with Jian Ghomeshi. Hall stated he did not believe Dexter glamorized serial killers but acknowledged the connection was horrifying, saying, 'it seems that Dexter had something to do with it.' In May 2013, it was reported that Twitchell had purchased a television for his prison cell and had caught up on every episode of Dexter he had missed since his arrest. The case has been the subject of several books and television features. Steve Lillebuen's 2012 true crime book The Devil's Cinema provides a detailed account of the case and trial, written with Twitchell's cooperation. Gilles Tetreault published his personal account, The One Who Got Away, in 2015. A film adaptation of The Devil's Cinema was acquired by producer David Permut, with director Sam Hobkinson attached. The case has been featured on numerous television programs, including Crime Watch Daily, Dateline NBC, 48 Hours Mystery, CBC's The Fifth Estate, and various true crime series on networks like Investigation Discovery and REELZ.

Incarceration and parole board proceedings

Mark Twitchell is serving his life sentence at the medium-security Bowden Institution in central Alberta. In a recent parole board hearing, he applied for temporary escorted leaves to visit his parents in Edmonton. The Parole Board of Canada, in its decision, noted that Twitchell was making behavioural progress in prison and would be a 'manageable risk' if given leave. Despite this assessment, the panel denied his application. A primary reason cited was the need to 'remain cognizant of the possible psychological impacts on the victims from you visiting the city in which they reside.' During the hearing, Twitchell offered his perspective on his crimes and their motivations. He continued to downplay the influence of the Dexter television series, calling it 'massively overstated' during his trial. He described his mindset at the time of the murder as being detached from reality while writing a script for a psychological thriller. 'I tried so hard to craft a convincing character who saw murder as a vocation,' he told the board, explaining he went down a 'rabbit hole' wondering about the experience of killing. He said he had been living a double life, lying to his then-wife about holding a steady job while secretly pursuing film work she did not support. Twitchell framed this period as an existential crisis that led to an erosion of his moral compass, though he maintained violence was not naturally part of his character and that he did not intend to hurt his victims.

Other documents and psychological profile

Beyond the 'SKConfessions' document used at trial, investigators found another revealing file on Twitchell's laptop that was not entered as evidence for the jury. This document was entitled 'A Profile of a Psychopath'. Investigators believed Twitchell authored this text, which presented a detailed self-analysis of his own personality and behaviour. While the contents were not detailed in open court, its existence suggests Twitchell was engaged in a deep, albeit twisted, introspection about his own psychological state. This aligns with his parole board statements about crafting a character and exploring a dark fantasy world through his writing. The document adds another layer to the understanding of Twitchell's mindset, indicating he was not only documenting his actions in a narrative form but also attempting to clinically analyze the traits he believed he embodied or was emulating.

Questions about Mark Twitchell

Who is Mark Twitchell and why is he called the Dexter Killer?

Mark Twitchell is a Canadian convicted of first-degree murder for the 2008 killing of Johnny Altinger in Edmonton. The media dubbed him the 'Dexter Killer' because his methods closely mirrored those of the fictional serial killer Dexter Morgan from the Showtime television series. Twitchell lured his victim online, murdered him in a plastic-wrapped garage he called a 'kill room', dismembered the body, and documented his actions in a confession file. His fascination with the show was a major theme at his trial, and he later watched all the episodes he missed while in prison.

How did Mark Twitchell lure his victim?

Twitchell created a fake female profile on the popular dating website Plenty of Fish. Using this persona, he communicated with Johnny Altinger and arranged a meeting at a garage he rented in Edmonton's Mill Woods area, presenting it as a date location. Altinger, believing the encounter was genuine, provided the address to friends as a safety precaution. This act ultimately helped police trace Altinger's last known whereabouts after he disappeared following the meeting on October 10, 2008.

What was the 'SKConfessions' document and why was it so important?

The 'SKConfessions' document, recovered from Twitchell's deleted laptop files, was the Crown's most critical piece of evidence. Its title stood for 'Serial Killer Confessions'. It began by stating it was based on true events and narrated a first-person account of planning to become a serial killer, including a failed first attempt and a successful second murder that matched the details of Altinger's death exactly. At trial, Twitchell admitted to writing it but claimed it was a fictionalized story meant for a film script, not a factual confession. The jury rejected this explanation.

What happened to Gilles Tetreault and why wasn't Twitchell convicted for that attack?

Gilles Tetreault was lured to the same garage weeks before Altinger's murder by the same online dating ruse. He was attacked by a masked man with a stun baton but fought back and escaped. He did not initially report it out of embarrassment. After Twitchell's arrest, Tetreault testified and was dubbed 'The One Who Got Away'. Twitchell was charged with attempted murder, but the judge ruled it could not be tried alongside the murder charge as a single transaction. After the murder conviction secured a life sentence, the Crown stayed and eventually dropped the attempted murder charge as there was no legal benefit to a separate trial.

Where is Mark Twitchell now and has he been granted any leave from prison?

Mark Twitchell is currently incarcerated at the medium-security Bowden Institution in Alberta, serving a life sentence for first-degree murder. He will not be eligible for parole until he has served 25 years. In a recent parole board hearing, he applied for temporary escorted leaves to visit his parents in Edmonton. The board acknowledged his behavioural progress but denied the application, citing the potential psychological impact on the victims' families should he return to the city where the crime occurred.

Has Mark Twitchell's case been featured in books or documentaries?

Yes, the case has been the subject of significant media coverage and several books. Steve Lillebuen's 2012 true crime book The Devil's Cinema provides a comprehensive account of the case and trial, and a film adaptation is in development. Gilles Tetreault published his personal memoir, The One Who Got Away, in 2015. The story has been featured on numerous television programs including Dateline NBC, 48 Hours, CBC's The Fifth Estate, and various true crime series on networks like Investigation Discovery and REELZ, as well as on podcasts and online channels.

Sources: Wikipedia and current public reporting, checked by the Nosy Mag desk. Last updated 2026-10-19.