Letters offer a rare look at the thoughts of "The Dexter Killer": "It's what it is and I'm what I am."

This story previously aired on April 23, 2022. It was updated on June 10, 2023.

These are the words of Mark Twitchell, written to investigative journalist and author Steve Lillibuen:

Steve Lillibuen [reading letters]: "It would appear that I'm unique in the world. There is no key. No root cause … If I really were capable of premeditated murder … Normal, healthy, well-adjusted 30-year-old men … I once heard the legend of another worthy victim … I dealt with his remains in a disrespectful manner that traumatized me forever … psychopathic serial killer … I quickly grew to resent and hate this man."

Steve Lillibuen [reading letter]: "It's what it is and I'm what I am."

Lillibuen is revealing the contents of Twitchell's letters. It's a rare look inside the mind of a killer.

Steve Lillibuen (reading letter): "Nobody would side with Dexter Morgan if he went around slaughtering schoolteachers and mail carriers on a whim."

Police say Twitchell was fascinated by the fictional character in the hit Showtime series "Dexter." Showtime is a division of Paramount Global, which owns CBS.

Steve Lillibuen: Twitchell's been dubbed "The Dexter Killer" because of the numerous links between the television series and the real-life crimes.

So how did this young Canadian filmmaker end up accused of horrific acts? The story begins in October 2008.

Det. Bill Clark | Edmonton Police: To hear how everything happened … it was like you're watching the movies … But now we have it happening in real life.

Det. Bill Clark: Gilles Tetreault was online on the plentyoffish.com website … Which is a dating site.

Tetreault, who was 33 at the time, was excited to meet the woman who called herself "Sheena."

Gilles Tetreault [driving]: I was actually late, so I was driving quite fast to get there.

Gilles Tetreault: She said … "I'll just leave the garage door open for you. And then you just go in through the garage."

Det. Bill Clark: I don't think he ever imagined in a million years what would happen to him in that garage.

Gilles Tetreault: It was dark … then I kind of looked around for the door she told me to go through … and that's when somebody came out … attacked me from behind.

Gilles Tetreault: Finally, I look back, and that's when I see this man — kinda hovering over me with a hockey mask … There's just this chill down my back, as I — wow, this is no date. 

Gilles Tetreault: He's about 6 foot and this black and gold hockey mask painted — all painted up on his face.

The hockey mask wearing man had ordered him to the ground at gunpoint.

Gilles Tetreault: And he tore a piece of tape and he covered my eyes with it. … I start hearing different things… like a jingling noise and stuff like that … my head is just racing, like it's like thinking, "What's goin' on?  What's he gonna do? Is he takin' another weapon out?"

Tetreault decided he wasn't waiting to find out.

Gilles Tetreault: I can't do this, I gotta fight back … so I got up and I ripped the tape off my eyes. … And he was stunned that I got up and started yelling at me to back down on the ground.

Instead, he grabbed the attacker's gun.

Gilles Tetreault: When I … grabbed the gun, I felt the gun was plastic. This is the greatest feeling I ever felt in my life, because then I knew I had a fighting chance to get away.

Gilles Tetreault: That's when I was ready to fight … I punched him and I felt really weak. I'm like "Wow, why was my punch so weak?

What Tetreault didn't realize was that he had been weakened by the effects of a stun baton.

Gilles Tetreault: And then he starts punching me on the side of the head.

Just about then, he came up with a plan.

Gilles Tetreault: He grabbed my jacket … I jerked forward to make sure he had a good hold on it, and I thought it's … the perfect time.

Troy Roberts: That was part of your plan, you're thinking he grabs my jacket, and I can get free …

Gilles Tetreault: Right. And that's when I slipped out of the jacket, rolled underneath the garage door and then got up…. And it worked.

Gilles Tetreault: And I tried to run and all of a sudden my legs wouldn't work … I just fell, boom right on the gravel driveway. … That's when he grabbed my legs and started pulling me back to the garage…. So, I'm like, "Oh no, what am I gonna do now.  I'm dead."

Tetreault was thrown back in the garage, but he surprised himself by rolling out again. This time, he managed to get into his truck.                      

Gilles Tetreault: I stuck the key in the ignition … and then I just sped away.

When Tetreault got home, he discovered the profile on the dating site had been deleted. And he did his best to erase his own memory.

Troy Roberts: Why didn't you go to the police immediately?

Gilles Tetreault: At first, I was in shock. I said- I told myself I'll do it tomorrow. And tomorrow came and I was…I felt so ashamed that I got duped.

Embarrassed and confused, Tetreault convinced himself that perhaps it wasn't as serious as he first thought.

Gilles Tetreault: I really thought it was a mugging at the time.   

But just one week later, another man, Johnny Altinger, would answer a similar dating ad and disappear. 

Gary Altinger: Where is he?  What's going on?  He wouldn't do this to us. 

Gary Altinger, Johnny's older brother, says the last time anyone heard from him was on October 10, 2008, when the 38-year-old left for a date with a woman named "Jen." 

Gary Altinger: Not a message, nothing. … And then, not showing up for work?  Totally out — out of character.  …  John was very, very, very responsible.

Troy Roberts: And when did you grow concerned.

Gary Altinger: When I received that email … And this e-mail was completely out of character.

Troy Roberts: What did it say?

Gary Altinger: I've met a woman named Jen.  And I'm going away with her to — Costa Rica and I'll call you at Christmastime."

Gary Altinger:  I just thought right away after I had read this, that's gotta be the weirdest message I've ever received.

That identical strange message had gone out to all of Johnny's friends as well. Desperate for some answers, Johnny's friends broke into his apartment.

Gary Altinger:  They found his passport.  And they found dirty dishes. And they found everything just like as if he were going to return an hour or two later … And with that information, then they went to the police, and they said, "Hey, listen.  You've got to do something." 

Det. Bill Clark: His red Mazda was missing. … He had taken his vehicle; it couldn't be found. So obviously that's what we're gonna look for first.  Easier to find a car than — than a person. 

Det. Bill Clark: Based on the emails, they talk about Costa Rica, the officers search all the parking lots at the airport … It's not found. … Everything's turning up negative. 

But there was one clue that would give police their first big break in the case. On the day he disappeared, Johnny Altinger had forwarded the directions of where he was going to friends.

Det. Bill Clark: Well, John's friends were concerned. … And his friend even questioned him on the email. You know, be careful … And John said, "Yeah, well, here's the directions. And if anything happens to me, you'll know where to look." 

Armed with the directions, police were led directly to that garage.

Det. Bill Clark: They learned, of course, the garage is rented out to an individual named Mark Twitchell.

Twitchell, then 29 years old, a married man with a young daughter, had used the garage as a set for a recent movie project. 

MARK TWITCHELL [graduation video]: "I'm glad I got to work with you all and I hope I see you all in the industry."

Twitchell denied knowing anything about a missing man or a red Mazda and he had no problem with the police wanting to search the garage.

Det. Bill Clark: They have a look around and they see some…what looks like blood.  And Mark Twitchell's explaining, "Oh, no, that's my movie prop.  We did a film about … killin' a guy in here and I filmed it all.  And I've been cleaning it up over the last couple weeks …"

Det. Bill Clark: And there are some things that were, you know, raisin' your Spidey senses in this one. Goin', "Yeah, this isn't right. … Something goin' on here."

QUESTIONS FOR THE FILMMAKER

For detectives in the Edmonton Police Department, the disappearance of Johnny Altinger was a mystery in more ways than one.

Det. Bill Clark: It's a missing persons case. … We don't know if foul play's happened here.  We — we don't have a body. We don't even know if we have a crime.

Their only lead was Mark Twitchell's film set garage. Voluntarily, the amateur filmmaker came down to the Edmonton Police Station to speak with detectives.

DETECTIVE [interrogation]: Altinger … Does that name ring a bell to you or mean anything to you?

MARK TWITCHELL: No.

DETECTIVE: Never heard it before?

MARK TWITCHELL: No.

Twitchell appeared to be eager to help. He had no history of violence and was hardly a suspect.  In fact, he seemed guilty of nothing more than wanting to brag about his film career.

MARK TWITCHELL [interrogation]: I'm working on a comedy right now. Which is a — it's actually a full-blown feature that's actually gonna have a decent budget in the neighborhood of about three-and-a-half million …

Twitchell's first film project, a "Star Wars" fan film, had received some media buzz back in 2007.

MARK TWITCHELL movie interview]: "The word has gotten around that I'm making a 100 million dollar movie for 60 grand, and some production and directing jobs have already come my way."

But the police were more interested in Twitchell's latest production: a suspense thriller called "House of Cards," where a hockey masked serial killer lures a man to garage via the internet and kills him.

DETECTIVE [interrogation]:  I mean it's kinda odd that you're filming that kind of thing.

MARK TWITCHELL: Mm hmm.

DETECTIVE:  And we end up going to that garage because of a missing person who supposedly went there.

MARK TWITCHELL: Yeah. It's really freaky too … And as soon as they called me on the phone …  I got this weird chill.

Det. Bill Clark: He looked pretty comfortable in the interview. … And when it was done and I watched, I went, "Wow, that guy interviewed well." 

Hours later, Twitchell even agreed to let officers back into the garage where he had filmed "House of Cards." Little did they know the case was about to take an unusual turn.

Det. Bill Clark: Detective Murphy goes, you know, and meets him and talks to him. And there's this huge revelation about "Oh yeah, I bought a red car off a guy." It's like — I remember getting the phone call at the police station just thinking "holy crap."

That's because police were still looking for Johnny Altinger's red Mazda. So, investigators called Twitchell again. And again, he voluntarily agreed to answer more questions. This time Bill Clark conducted the interview.

DET. BILL CLARK [interrogation]:  So, as you know Mark, we're just here trying to find this John fellow. John Altinger.

MARK TWITCHELL:  Mm hmm.

Clark listened while Twitchell told him how he came into possession of a red car — a detail he failed to mention when he spoke with police earlier.

MARK TWITCHELL [interrogation]: This guy, uh, taps on my window …  you know, "Hey buddy do you wanna buy a car? … I — I've shacked up with this really rich lady …  She's even gonna buy me a new car … so I'm just looking to unload mine… how much do you have on you?"

Twitchell claimed he bought the red Mazda for just $40, and that it was parked at a friend's house.

Troy Roberts: What are you thinking when you hear that? That he purchased a car for $40? 

Det. Bill Clark: I just thought, "That's unbelievable." Right away I'm saying to myself this is a bunch of crap.

The strange story about the red car, the serial killer movie being filmed — for Clark it could only mean one thing.

DET. BILL CLARK [interrogation]:  There's absolutely no doubt in my mind that you're involved in the disappearance of John Altinger. No doubt in my mind at all Mark.

MARK TWITCHELL: Why?

But it was only a hunch. Clark had no hard evidence against Mark Twitchell. Police began digging deeper into his background. They were interested in speaking with anyone who had worked on "House of Cards," where actor Chris Heward's character meets an untimely, bloody end in the film.

Chris Heward: My character was killed with a samurai sword. … They said they would have a mannequin or a dummy to run the sword through, and when I got there, there was none. … When I looked at the weapons … that was my first sign. … When I saw that they were real, I thought, "This is off. … Why didn't I tell somebody where I am?"

Heward left the garage film set unharmed but rattled. His unease only escalated when police asked him about that allegedly fake movie blood they spotted in the garage.

Chris Heward: "How much of the blood splatter on the wall was from your filming?"  I said, "None of the blood splatter was from us."

And then, in a search of Twitchell's belongings, police found his laptop.

Det. Bill Clark:  They pulled off the hard drive a deleted file … titled "SK Confessions."  

"SK Confessions." Police believed "SK" was shorthand for "serial killer."

Det. Bill Clark: One of the first lines … it says — "I'm not sure when I decided to become a serial killer, but it was a feeling of pure euphoria."

"SK Confessions" told the story of a man who was lured to a garage and stabbed to death — a plot strikingly similar to "House of Cards."

"SK CONFESSIONS" PASSAGE: "I plunged the knife deep into his neck …"

Det. Bill Clark: It was unbelievable. … I just remember reading it all and just was fascinated by this document going, "Holy mackerel."

But was the document a screenplay?  Or was it in fact Mark Twitchell's confession of murder?

THE "DEXTER" CONNECTION

Two weeks after the disappearance of Johnny Altinger at a garage film set, police had sharpened their focus on filmmaker Mark Twitchell.

Det. Bill Clark: It just doesn't make sense. … where there's smoke there's fire.

Police cameras were rolling as a forensics team processed Twitchell's family car and the garage he rented.

And a few miles away, detectives had been at the Twitchell home where they found Jess Twitchell — Mark's unsuspecting wife of two years.

Det. Bill Clark [in car in front of Twitchell's house]:  What I said was, "We're investigating a missing persons. I believe your husband's got somethin' to do with it … and this quite possibly — you know, could be a homicide."  I didn't really go into anything more, but I think that was enough. I mean, she was emotional.

Police soon discovered that the Twitchell marriage was already fractured.

Det. Bill Clark:  They had been livin' and basically sleeping in separate bedrooms. She was basically livin' on the main floor, he was livin' in the basement.  So, there was obviously troubles in paradise there, we knew that ...

Mark Twitchell had been having an affair with an old girlfriend and lying to his wife about having a job.

Det. Bill Clark: We found out he was telling his wife he was going to work every day. He had no job. … He was getting his friends to invest in his alleged movie-making business with his Hollywood connections … And basically, Mark Twitchell was living off their money.

Interestingly, the document police had found in Twitchell's laptop titled "SK Confessions" also referenced a crumbling marriage and secrets.  It read "I went through great lengths to bring my wife over to the comfortable belief I wasn't cheating on her."

Det. Bill Clark: It was basically almost like a movie script.

But what was real and what was fiction? The closer police looked, the more the lines blurred. Police discovered Twitchell spent countless hours making elaborate Halloween costumes.

Det. Bill Clark: It's almost like, at times, Mark Twitchell lives in a fantasy world.

But it was Twitchell's Facebook page — comparing himself to TV's fictional serial killer Dexter Morgan — that really raised eyebrows.

"Mark has way too much in common with Dexter Morgan" read Twitchell's status. 

Det. Bill Clark: He talked a lot about how he loved the show "Dexter."

Twitchell even posed as Dexter Morgan on Facebook.

Renee [reading Facebook message]: "We all have a dark side, some darker than others and you're not the only one to relate to Dexter. It sometimes scares me how much I relate. I mean look at this profile."

That profile had caught the attention of a woman named Renee from Cleveland, Ohio. 

Renee: I'm a huge fan of the Showtime show "Dexter." … So, I thought, "Oh, well, you know, I'll be friends with him."

Eventually, Twitchell revealed his true identity.

Renee: He was a filmmaker … and he was working on — a new thing called "House of Cards."

Renee was intrigued. After all, she was an aspiring writer and a friendship with a movie maker could open doors.

Renee: I thought it was gonna be like a working relationship, a working friendship. You know, we had a lot in common. 

Troy Roberts: So, I mean, you spoke to him a couple of times a day online?

Renee: Couple of times a day.

Troy Roberts: Was it flirtatious?

Renee: Oh, yeah.  Absolutely.

Their email exchanges soon became dark. It was shortly before Johnny Altinger disappeared.

Renee: We talked about— you know, serial killers … and, you know, the psychology behind a serial killer.

At the time, Renee was upset with her ex-husband's new wife. 

Renee: And I wanted her dead, at the time. … But I said I couldn't do it. … And hypothetically, how would you get away with it? 

Troy Roberts: How do you get away with it?

Renee: He said, "You cut her up in little pieces.  You put her in trash bags, like Dexter."  And since I was close to the lake, "You rent a boat and — dump her out in the middle of Lake Erie."

But then, she began to wonder.

Renee: He said over the weekend he did something, and he liked it. … "I crossed the line and I did something and I liked it"

Troy Roberts: And what did you take that to mean?

Renee: That he killed somebody. What other line is there to cross? … Something inside my head just gave me red flags and said, "He did it."

And her suspicions kept growing with another email he sent.  

Renee [reading email]: "There's an enormous missing person, possible homicide investigation going on centralized around a location I've rented for film work. … So of course the police have tossed my house and impounded my car … Not fun considering they won't find anything …"

But Twitchell had underestimated the police.

Det. Bill Clark: He thought he was way smarter than the police.  One of the biggest mistakes I think that he made was he had no idea how we do our job and that was a huge advantage to us.

Adding to their circumstantial case: Twitchell possessing Altinger's car, the "SK Confessions" document and his "Dexter" obsession. Investigators finally had hard evidence — they had found Altinger's blood in Twitchell's trunk. 

Det. Bill Clark: When we got the word that the DNA matched, we briefed our tactical team—our arrest team, and we had officers ready to make the arrest.

On Halloween morning 2008, while Twitchell was putting the finishing touches on his Halloween costume at his parents' home, police were busy laying a trap.

Det. Bill Clark: We got an undercover operator to work the internet and pretend he was gonna — an investor. … He was lured out on the promise to meet this guy at this coffee shop … And when he got about three blocks from his house, the tactical team swooped in on him and took him down. Tough guy Mark Twitchell peed his pants he was so scared. And it was a little taste of his own medicine, I guess.

Back at the station, Detective Clark and Mark Twitchell came face to face in the interrogation room once again.

DET. BILL CLARK [Mark Twitchell interrogation]: As I told you that night, I knew that you were involved in the disappearance at that time of Johnny Altinger. That's changed slightly … I now know that you killed John Altinger.

Three weeks after Altinger's disappearance, police charged Twitchell with first-degree murder. The once talkative movie director barely uttered a line.

Troy Roberts [watching interrogation video]: You didn't get much of a reaction, did you?

Det. Bill Clark: No, he's uh — well he knows not to say anything … he's talking to his lawyers. He's not gonna admit to anything.

He didn't have to. "SK Confessions," which police had been dissecting word by word, spoke volumes. They were now convinced it was no screenplay, but rather a diary of murder.

One passage about a knife read: "I thrust it into his gut. His reaction was pure Hollywood."

Det. Bill Clark: We do believe, as investigators, that the account written by Mark Twitchell in that "SK Confessions" is exactly what he did to John Altinger.

By now, Renee had called police. As authorities began building their case, there was one crucial part of "SK Confessions" they wanted to verify … about a victim who had survived.

Det. Bill Clark: It was just a huge piece of evidence 'cause not only would it verify what was written in "SK Confessions"… it would also have — a living witness … so it was paramount that we find this person.

THE MAN WHO GOT AWAY

Detective Bill Clark knew his next move was finding the alleged victim who had escaped from Mark Twitchell's garage.

Det. Bill Clark: You know, one of the first things we did was check the police records … figuring hopefully someone called the police on this.  And we have nothing.  

But police had found a helpful clue during the search of Twitchell's home.

Det. Bill Clark: One of the things they had found was a hockey mask…the "SK Confessions" talked about how … Mark Twitchell had worn this mask when he attacked both victims.  But we figured it was something the first victim would key on. 

Police soon took to the airwaves.

DET. MARK ANSTEY [to reporters, holding up hockey mask]: We have some details on this male victim who was attacked, and we would like him to come forward.

Gilles Tetreault was at home oblivious to the horror he had escaped when a friend told him to watch the news.

DET. MARK ANSTEY [to reporters]: To date we do not know who this victim is…. I believe the victim entered the garage and was attacked by another male who was wearing a hockey mask …

Gilles Tetreault: And it's the same hockey mask that I saw. … Wow, yeah, this is — this is the guy. This is what happened to me. It's the same mask, everything.

What Tetreault heard next came as an even greater shock. Another man had been lured to the same garage and met a gruesome end.

DET. MARK ANSTEY [to reporters]: We have not found John Altinger's body.

Troy Roberts: And what were you thinking when — when you heard this?

Gilles Tetreault: I couldn't believe it. … Once you — find out the whole story … I knew at that point it was not just a mugging.  It was actually — he was probably going to kill me. …  And I'm like, "Wow, I— I have to go forward now. I have to come forward."

Exactly one month after he was attacked, Gilles Tetreault walked into the Edmonton Police Department and told police his incredible story.

GILLES TETREAULT [police interview]: I was off balance, I couldn't run … I fell down on the gravel driveway and, uh, basically crawling. … So, he dragged me back to the garage.

Tetreault's story matched nearly word for word what was in "SK Confessions."

"SK CONFESSIONS" PASSAGE: "I grabbed him by the leg as if to drag him back into the garage caveman style."

Det. Bill Clark:  So, I know that this diary we have is true. 

GILLES TETREAULT [police interview]: After this all happened, I realized how lucky I was. 

Seven days after Tetreault was attacked, police say Twitchell wasn't going to make the same mistake twice.

Troy Roberts: How did he kill John?

Det. Bill Clark: We know that he lured him to the garage in the same way he lured Gilles Tetreault. … And then in this case … because he learned from Gilles that the Taser didn't work, he hit him over the head with a lead pipe.

"SK CONFESSIONS" PASSAGE: "Please stop hitting me … oh my skull."

Following the narrative, police believe Altinger was then stabbed and dismembered on a makeshift autopsy table.

Troy Roberts [outside Twitchell's garage]: What was the most damning piece of evidence that you discovered?

Det. Bill Clark: We had a, you know, luminol tests done on the floor. … Large amounts of blood had been spilled on the floor of the garage. … Probably one of the … biggest pieces, a piece of tooth that was found inside there.  That piece of tooth matched up to our victim.

According to "SK Confessions," the killer then broke into Altinger's apartment and sent out those emails about taking an exotic vacation.

The killer then attempted to burn the remains in a barrel but failed. He next tried to dump them into the river but was afraid of being seen.

Det. Bill Clark: Ultimately Mark Twitchell drove around with it, according to the "SK Confessions" document. … He even talked about driving around with him and pulling up beside people at red lights and looking at them thinking that "they don't know I have a dead body in the trunk of my car."

But where was Johnny Altinger's body? "SK Confessions" described the killer finally choosing a sewer to dump the remains, but that's where the pages stopped.  It was a story without an ending.

Det. Bill Clark: In any homicide investigation you obviously want to bring closure to the family… So not only do you want to make that phone call saying, "We got the guy that did this to your loved one," but in this case, we wanted to say to 'em, look, "we found Johnny."

Detective Clark hoped Twitchell would provide the final chapter.

DET. BILL CLARK [interviewing Twitchell]: I'm gonna go get the car ready.  We're gonna take a drive.

Troy Roberts: You guys were driving around and there was a camera trained on him in the back of the police car. Tell me about that.

Det. Bill Clark:  When you — you read all the experts' books about these type of individuals is they tend to like the media attention. … So, we thought, "Well, maybe if we drive him around and we'll put a camera on him, maybe he'll just — we'll just take him to places," 'cause we had no idea where — where Johnny remains were at that time.

DET. BILL CLARK [to Twitchell in police car]: So, in order to finish the movie, we have to find the body, take it back to the people, the family — done.  Movie's over. And you can write it all down. 

Detective Clark was relentless, taking Twitchell on a tour of his old neighborhood.

Det. Bill Clark: And we first drove to his parents' house where he had been staying. … We actually … demanded that he tell us. He wouldn't. 

DET. BILL CLARK [to Twitchell in police car]:  Look familiar Mark? Are we parked right on top of the sewer where you dumped the body?

Next stop, the scene of the crime.

DET. BILL CLARK [to Twitchell in police car]: So here we are back at the killing garage. The "Dexter" garage.

OFFICER [to Twitchell outside garage]: Bring back any memories? You wanna tell us where the body is now?  Get this over with? 

But Twitchell remained silent. So, police kept searching on their own, looking in sewer after sewer.

Det. Bill Clark [driving]: So, all these manhole covers were pulled off in this alley. … So anytime I'd seen one I'd always have my flashlight with me and would get out and actually take a look.

Weeks, then months, passed and still no luck. Then a year-and-a-half after Johnny Altinger disappeared, Twitchell, while awaiting trial, broke his silence and gave the police a map.

Investigators followed it to an alleyway just a half block away from where they had stopped the search.

Det. Bill Clark [with Roberts at sewer]: And he had marked an "X," "X" marks the spot, and took us right to this sewer cover here. … We could see what looked like pieces of human torso down there.

In March of 2011, Mark Twitchell went on trial for the murder of Johnny Altinger. Prosecutors called Gilles Tetreault to testify, and to prove that what Twitchell described in "SK Confessions" was not a work of fiction but an account of what had actually happened.

Gilles Tetreault: I wasn't really afraid of him at that time. … I knew he couldn't hurt me anymore.

The only witness the defense called was Mark Twitchell and he had one unbelievable tale to tell. Steve Lillibuen, a college professor and an investigative journalist, was covering the trial for the Edmonton Journal and went on to write a book, "The Devil's Cinema," about the case.

Steve Lillibuen: Mark Twitchell testified … that this was all a big misunderstanding … he had killed Johnny in self-defense …

Twitchell claimed that Altinger's death was nothing more than a publicity stunt gone horribly awry. He said he intended to let both men go so they would create a buzz for his film by telling people that this had actually happened to them. But he claimed Altinger became enraged at being tricked, and he accidentally killed him in self-defense.

Steve Lillibuen: He blames Johnny, saying it was Johnny's reaction to his attempt at this promotion is what happened.

In the end, the jury took just five hours to find Mark Twitchell guilty.  He was sentenced to 25 years to life. But for Lillibuen, there were still so many questions.

Steve Lillibuen: So, the motive is the mystery, the why did he do this. … What's Mark Twitchell's psyche? What led to this happening?

Questions Lillibuen hoped might be answered when he got a call out of the blue from Mark Twitchell himself.

Steve Lillibuen: He just said straight out, "If you're gonna be writing a book about me, you might as well come straight to the source."

A KILLER'S OWN WORDS

Steve Lillibuen: The first time I met him, he actually had me laughing. … He's very charismatic.

Mark Twitchell was nothing like author Steve Lillibuen expected.

Steve Lillibuen: He has very much that salesman slick behavior, he knows how to put it on to get people to like him.

Twitchell began writing to Lillibuen before he was even convicted in 2011.  Over the course of almost three years, they exchanged dozens of letters.

Steve Lillibuen: I learned really quickly that he preferred to talk through writing.

Troy Roberts: These weren't ramblings of a crazy man. There was actually some substance in these letters?

Steve Lillibuen: Yes absolutely. So, he's not crazy. He is lucid.

At first, Lillibuen didn't want to push Twitchell away with too many probing questions about his crimes.

Steve Lillibuen: I asked him a lotta softball questions just about who he was, his family, his upbringing -- all that kinda background detail.

Steve Lillibuen: He was newly married and a new father. So he was, you know, just a typical local guy who had dreams of making it big in Hollywood and really no red flags. No warning signs that something like this was on the horizon.

In letters, Twitchell clung to his defense that he had no choice but to kill Johnny Altinger and then dismember him.

Steve Lillibuen [reading letter]: He writes, "I killed Johnny Altinger in a horrific accident of self-defense. After cursorily shoving aside my human sensibilities, I dealt with his remains in a disrespectful manner that traumatized me forever."

Steve Lillibuen: ... still is adamant ... that this was not a planned and deliberate murder … and to be frank, he is wrong.

Lillibuen points to "SK Confessions," where Twitchell describes how he turned that garage into a kill room, set up a makeshift autopsy table, had plastic sheeting, and a processing kit similar to the one Dexter Morgan used. 

Steve Lillibuen: Mark Twitchell wrote to me quite extensively about his interest in "Dexter."

"Dexter" on his mind, Twitchell drew a portrait of Michael C. Hall – the actor who plays him.  And to Lillibuen's surprise, even behind bars Twitchell was able to feed his obsessions.

Steve Lillibuen: Mark Twitchell had actually been granted access to finish watching the series while he was incarcerated.

In 2012, Michael C. Hall was asked about Mark Twitchell on a Canadian radio program.

MICHAEL C. HALL (audio): it is horrifying to entertain the notion that something you did inspired that.

Twitchell's response to Hall's comments was to downplay his fascination with the "Dexter" character.

Steve Lillibuen [reading letter]: He wrote to me "As you are aware, Dexter has almost nothing to do with my case."

Throughout their correspondence, Lillibuen continued to grapple with what drove Twitchell and then Twitchell told him: 

Steve Lillibuen [reading letter]: "There is no key. No root cause …there is no school bully or impressionably gory movies … or Showtime television series to point the finger at. It is what it is and I am what I am."

Julia Cowley: He's a depraved individual, and he knows that.

Retired FBI criminal profiler Julia Cowley didn't work on this case, but she spoke with Detective Clark and reviewed Mark Twitchell's writings and letters for "48 Hours." She thinks she knows what made Twitchell tick.

Julia Cowley: I think he identified with Dexter to some degree.  … I think he is different than Dexter.

Julia Cowley: He's not killing bad guys. He is killing very innocent, good people living productive lives.

Julia Cowley: And while he's technically not a serial killer … he was headed in that direction if they hadn't have caught him.

Cowley believes Twitchell took pleasure in planning and executing his crimes as if they were romantic trysts.

Julia Cowley: I think the primary motivation was sexual. 

Troy Roberts: Sexual? 

Julia Cowley: Yes. … He is targeting men that perhaps he would be interested in having a date with. … It's a combination of a sexual motive and thrill killing.

Julia Cowley: He is pretending to be a woman ... He … writes extensively about … what he's going to wear, the weapon that he chooses. He sort of describes it in seductive language. "I wanted the weapon used for the deed itself to be simple, elegant and beautiful."

And in a strange twist, Twitchell's been able to feed that obsession too. In 2017, he was allowed to join an online dating website for inmates.

Steve Lillibuen: Which, you know, I find quite surprising considering that the way he ended up in prison … I believe it's been taken down since then.

The man who was tricked into that very bad date in Twitchell's garage, Gilles Tetreault, continues to be haunted by the experience. Tetreault, who has written a book about his ordeal, spoke to "48 Hours" recently.

Gilles Tetreault: I still think about the painted-up hockey mask. I still think about the stun gun. You know, the fight for my life —

In 2023, Twitchell will be eligible to apply for early parole. Experts say it's a long shot, but it worries Tetreault.

Gilles Tetreault: I'm scared that he might want to finish what he started and come after me. 

Julia Cowley: Mark Twitchell cannot be rehabilitated. This is who he is.

And for Mark Twitchell, the aspiring filmmaker, there may be one final plot twist.  Author Steve Lillibuen sold the rights to his book "The Devil's Cinema" to a film company.  Twitchell's story may be coming to the big screen. 

 

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Produced by Asena Basak. Michael McHugh is the producer-editor. Lourdes Aguiar and Anthony Venditti are also producers. Joan Adelman and Michelle Harris are the editors. Patti Aronofsky is the senior producer. Nancy Kramer is the executive story editor. Susan Zirinsky and Judy Tygard are the executive producers

In:
• 48 Hours
• Murder

Troy Roberts

Correspondent, "48 Hours"