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  • Writer's pictureThe True Crime Edition

The Dexter Copycat Killer

He'd already picked out another two victims.

Days after Johnny Altinger had disappeared, his friends decided to break into his home. Police had refused to help them as he was an adult, but they knew their friend hadn't gone on holiday; he was missing.


On Friday the 10th of October 2008, Johnny was getting ready to meet a woman he'd been chatting to on the dating website Plenty of Fish. They were getting on well, and the 38-year-old had told his friends about the plans he'd made that evening. He was excited.

Johnny Altinger via

Johnny worked as an oilfield equipment manufacturer and loved technology. As he got older, his adoration for computers moved to motorcycles, and he'd spend his weekends riding motorbikes with his best friend, Dale. He owned a Honda 500 cc and a Yamaha 1200 cc sport touring bike and treated them like children.

It was the Canadian Thanksgiving weekend, and instead of going out for dinner, they'd decided to go to her house instead. Johnny's friend, Dale, told him that he was concerned about his friend meeting up with someone he'd never set eyes on before, mainly because they weren't meeting on neutral ground. Jen's profile photo showed a brunette on the beach in a bikini, and his friends were surprised that this woman was talking to their friend, who was a self-confessed nerd.

Dale's concern grew further when Johnny told him that the woman hadn't given him an actual address but cryptic directions to her home. Dale didn't want his friend to miss out on the opportunity to meet someone, so he asked Johnny to send him the address of her house when he got there.

Instead of a text with her address, Dale received a call from his friend telling him that the woman he was supposed to meet wasn't there, but instead, there was a random man in the garage, filming a movie. The whole situation was odd, but Johnny hung up the phone, and Dale assumed his friend would go home and he'd speak to him later or the next day.

Around 7.30 that night, Dale received an email from Johnny telling him that Jen was home and that he was going back to the house to meet her. Dale was glad his friend would be meeting his date, but his concern was still there, and later that night, he called Johnny's phone to make sure he was safe.

This time, the phone rang and finally went to voicemail. Dale eventually went to bed, and the following day when he tried to call Johnny again, he still didn't pick up his phone. The day turned into night with no word from Johnny, and on Sunday, when he didn't turn up to a planned motorcycle ride with Dale, his concern grew further.

With still no word, Dale, his wife and another friend drove to Johnny's home to see if he was there. They rang his doorbell and banged on the door, but Johnny didn't answer, and a peek through the back door showed that no one was inside. The door was locked, so the trio went to his garage to see if his car was there. His red Mazda hatchback was gone, but his motorbikes were still in position, but they were uncovered, which was unusual for the enthusiast who always covered his bikes if he was away from home.


The next day, Dale received an email from Johnny.

The email from Johnny to Dale via

Dale wasn't convinced by the email. Johnny didn't like hot weather, and the email didn't read like one of his regular emails, so Dale responded to the email with a lie to see if he could catch out the writer. He replied to the email asking who would pick up Johnny's brother from the airport if he was on holiday. He didn't get a response.

Dale reported his friend missing to the Edmonton police department, but because he was an adult, there was little they could do.

The next day, Johnny's boss received an email from him, resigning from his job. The email was short and gave little explanation as to why he was leaving, and Johnny's boss replied asking for a forwarding address for his final paycheque. He didn't get a response, either.


No sooner had he disappeared was Johnny back online. He deleted his Plenty of Fish profile, changed his MSN screen name and even began posting social media updates. Dale and his friends breathed a sigh of relief that their friend was seemingly fine, and their worries began to subside.

However, their friend still wasn't responding to messages and calls, so Dale went back to the police and told them that they needed to look into Johnny as a missing person. They told him they needed more evidence that Johnny was missing, but they agreed to take a statement from Dale. They told him that the officer would meet him to go over the facts, but the officer never turned up.

Johnny's friends were desperate to find out where he was, so they went back to Johnny's home and managed to get through a window to find evidence that Johnny was missing and not just on holiday.

They searched Johnny's home, and they noticed that it didn't look like the apartment of someone who had gone on holiday. There was uncovered food in the kitchen and dirty dishes in the sink, but there was also no sign that he'd taken anything with him on his vacation.

His luggage and toiletries were still in the apartment, as was his passport.

Dale called Edmonton police to file the missing person's report, and a week after Johnny disappeared, the search for him finally began.


Police were sceptical about Johnny's disappearance. He was a grown man who'd met someone online, had fallen for her and had decided to go on holiday. He'd been active online, updating his social profiles and emailed his friends, so for all intents and purposes, he wasn't really missing.

They began searching for his car at long-stay car parks near the airport and contacted airlines that flew to Costa Rica to see which flight he'd taken. They also called customs in Costa Rica to make sure he'd got through when he'd landed. But their search came up empty; no one had seen him or his car.

They contacted Johnny's friends and colleagues, trying to determine if anyone had spoken to him on the phone or in person. Eventually, they found out that the last known sighting of Johnny had been on the Friday night when he'd vanished.

Edmonton police soon realised that Johnny might actually be missing, and they began to piece together the information they had about the date he'd gone on. Dale told them about his meeting with Jen, and he gave them the strange directions to the house where she'd agreed to meet Johnny.

The garage on via Edmonton Crown

Police arrived at the garage with the rolling doors, and nothing looked out of the ordinary, so they spoke to neighbours around the area to see if they'd seen anything that night or could tell them any details relating to the property. They found out that the garage was part of a rented property, but they were hired by two separate people, neither of which were called Jen.

They eventually found out that the garage was being leased to a film director named Mark Twitchell, who'd been using the space as a movie set. The windows were blacked out to stop unwanted light filtering in during takes so that police couldn't see inside.

Mark Twitchell via

They called the filmmaker, and when Mark Twitchell spoke to the police, he cooperated with them. He told them that he didn't know anything about Johnny and hadn't seen him that night. They asked Twitchell to come down to the garage and see inside the space, as they couldn't see inside. When he arrived, Twitchell showed officers around the back of the garage to let them in through the back door. As he turned the corner, he suddenly stopped as he noticed the broken padlock holding the door closed. He told police that the padlock wasn't his and that someone had changed it out for another, but it wasn't secured properly, and it was quickly broken.

When they entered the garage, they were all hit with a strange odour that smelled like something had been burned in the garage a long time ago. In the middle of the room was a large stainless steel table, with a receipt on top of it, showing several cleaning items, including paper towels, bleach, gloves and plastic sheets. The scene was disturbing, but Twitchell was beginning to foray into horror films, so the items in the garage, although strange, weren't out of place.

Twitchell agreed to go to the police station to give a formal statement, and by the time they sat down, it was 3 am, but he was happy to provide as much information as he could. In the interview, police noticed that Twitchell had a lot of energy, considering the time of night. He spoke to them about his career in filmmaking, his wife, Jess and his 8-month-old daughter, Chloe, his Star Wars fan fiction films he'd made in the past and how he was now funding his films through investors.

Investigators thought it was strange that Johnny Altinger had gone missing from the same place that a bloody horror movie was being filmed. Still, police didn't see Twitchell as a suspect, and when his interview tape was played back, there were no signs of him lying or deceiving investigators in any way.

But Mark Twitchell's story would soon begin to unravel.


The 28-year-old was born in Edmonton, Alberta and had always dreamed of making films. The year before, he'd directed a full-length Star Wars fan film called Star Wars: Secrets of the Rebellion, which included a cameo from original Boba Fett actor, Jeremy Bulloch. Although he loved science fiction, he also enjoyed the horror genre.

The movie that had just wrapped, House of Cards, was about a vigilante serial killer who targeted villains and was a homage to Twitchell's favourite show, Dexter. In his movie, the killer lured in the bad guys by posing online as a beautiful woman, and when they met her for a date, they'd instead be confronted by the serial killer. He'd take their money, torture them for bank information and then kill them.

The serial killer got away with the crimes by interacting with their family and friends online to make them think the victim was still alive and had gone away on vacation.

Police requested a warrant for the garage to search for evidence that Johnny had been there, but the judge denied their request, stating they didn't have enough evidence that a crime had been committed. Instead, they asked Mark Twitchell if they could have a look around, and he agreed. However, before they could get back into the garage, Twitchell told police about a series of strange events that had occurred in the previous few days.

He told them that belongings had been stolen from his car, and he'd found his front door unlocked. He also said that while sitting in a car park in his car, a stranger had knocked on his window and asked if he wanted to buy his red Mazda hatchback. The man told him that he was selling his car because he'd met a woman who was taking him on holiday for a while and didn't need it anymore. Twitchell told police he'd bought the car for $40 from the man.

Investigators asked Twitchell to come down to Edmonton police station again to write up a statement about the break-in, the stranger and the car, and he agreed. He wrote them an eight-page essay about the incident and told police that he believed that whoever broke into his home had taken specific items, including rubbish bags, paper towels and duct tape. He also said to them that he thought something had been burned in his back garden.


The seasoned investigators on the case had long known that Twitchell's story was a complete fabrication, so they told him that they knew he was involved in Johnny's disappearance. Twitchell vehemently denied his connection to the missing man and by 6 am, investigators called an end to the interrogation. They knew that he was involved in Johnny's case, but they didn't have enough evidence to keep him in the station, so instead, they seized his car and house and put a 24-hour detail on him to track his movements.

Officers searched Twitchell's home and found a plethora of science fiction memorabilia and film posters. They also found books about forensic science, serial killers and a guide to Costa Rica. Along with a pile of blank postcards, police also found a black hockey mask with gold stripes, which appeared to have blood on it.

In Twitchell's car, police found dozens of post-it notes with mundane messages scrawled on them, but there were a few that piqued the attention of investigators, stating "kill room clean sweep".

The post-it note via

A bag found in the car contained a military knife stained with blood, and inside the car's trunk, police found a bloodstain on the carpet and a steak knife that was also stained with blood. Additionally, they uncovered a laptop in the car, which included two temporary files, one of which was named SK Confessions. The document inside can be read here.

The document was 35 pages in length and outlined the actions of a serial killer with a wife named Tess and an 8-month-old daughter named Zoe.

The document read that the killer wanted to target married men who were cheating on their spouses, but he feared that they'd be missed. Instead, he decided to focus his killing on middle-aged, single men. It outlined what the killer would wear when he murdered the men; a black hockey mask painted with gold stripes and a black hooded jumper and told of how he would murder his victims, in a kill room on a metal table, like Dexter.

The document read like a confession, and police took it as such, but the journal also wrote about another target who had managed to escape from the killer a week before the second murder. The document said that the man arrived at the garage and was attacked with a stun gun but didn't go down. Instead, he fought his attacker and got away in his car.

Believing the second man could have been married and didn't want to report the attack, police took the document as verbatim and got a warrant to search the garage, which, this time, was granted by a judge.

When they arrived, the garage was immaculate. In the police's search, officers found a stun gun, a bb-gun that looked like a real pistol, duct tape, handcuffs and a lead pipe wrapped in tape that was covered in dried blood. In fact, the entire garage had been drenched in blood, leading forensics to believe that someone had been savagely beaten to death, likely by the pipe. There were also masses of cleaning products, masks and coveralls. Officers also found a game processing kit for cutting up large animals, and police already knew Twitchell wasn't a hunter.


On the 31st of October, Mark Twitchell was finally arrested and charged with first-degree murder and attempted murder. Police didn't believe Johnny was the first person to visit the garage, and when a press conference was held, announcing Twitchell's arrest, they showed the hockey mask and urged other victims to come forward. Two days later, they received a call.

Gilles Tetreault was the man who was attacked in the garage a week before Johnny Altinger's death. He was embarrassed, so he'd not reported the assault to the police, but when Johnny's death was linked to the mask, he knew he had to come forward.

The case was quickly building against Mark Twitchell, but there was still a missing body to find. Police spent months trying to locate Johnny's remains, but their searches came up empty. It wasn't until 18 months later when Twitchell told police where to find him, that he was brought home.

As the document said, Johnny's body was found in a sewer drain, two blocks from Twitchell's parents' home.

Once Mark Twitchell's arrest had been made public, his wife Jess had filed for a divorce from him. She hadn't seen him since the day police had seized her house, and she'd also found out that he'd been sleeping with his ex-girlfriend and had been talking to other women online.

He'd also been lying to her about his job. He'd quit months before, and instead of going to work in the mornings, he'd spend the day at the garage or his parents' house during his work hours and would arrive home at his usual time.

At trial, Mark Twitchell pleaded not guilty to the first-degree murder of Johnny Altinger, citing self-defence instead. He stated that the attacks were supposed to be a PR stunt, where his victims were meant to escape and cause a buzz around his new movie, but Johnny had fought back, and Twitchell had accidentally killed him.

The jury didn't buy his story, and after just five hours of deliberation, they found him guilty of first-degree murder, and he was eventually sentenced to life in prison with no parole for 25 years. He was transferred to Saskatchewan Federal Penitentiary, where he remains to this day. He is now 41 years old.

Gilles Tetreault went on to write the book, The One Who Got Away, which details his account of how Mark Twitchell attacked him inside the garage. Unfortunately, the book is now out of print.

Johnny was finally laid to rest at Victory Memorial Park in Vancouver.


In the document, SK Confessions, the killer had already picked his next two victims and likely had many more mapped out for the future. Because Johnny had told his friends where he was going, he likely saved many more people from the same fate.


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