"The Dexter Killer" | Full Episode | Forensic Files

[Music] I'm Julia Cowie, retired FBI agent and profiler and former special agent, forensic scientist
with the Tennessee Bureau of Investigation. This podcast is about criminal profiling.
This is certainly an unusual case. I've never seen anything quite like this one.
With many serial killers, it's the killing part that they enjoy and once they've killed the person, they're done.
Not Mark Twitchell. Action. Mark Twitchell was an aspiring filmmaker. [Music] I interviewed him for my book and we
corresponded uh for a number of years. He wrote me probably 30 or 35 different letters up to about 350 pages of
letters. In one letter, Mark Twitchell wrote wrote back to me and this is what he said. The fact is society in general
has a deep and profound fascination with the dark side of human nature. I do think Mark Twitchell was using the
film making as an outlet to live out his fantasies and it ultimately wasn't enough for him and that's why his
fantasies crossed into reality. I think Mark Twitchell believes that he is very smart, very methodical,
very logical, very levelheaded, much like the character of Dexter Morgan. And so I think he got ideas from the
show. I think he was drawn to the character because that's what he wanted to be.
There's significant links to Dexter. He had a kill room set up with plastic sheeting. He had a table set up for his
victims. He had this kind of processing kit that was very similar to what Dexter
uses. Never once did it cross his mind he'd ever be caught. They aren't going to
catch me. I'm too smart. Nothing's going to lead him to me. Our job is to put together the pieces of
the puzzle. And in this case, we had a written document. There was this document titled SK Confessions found in
a deleted form on Mark Twitchel's laptop and it appeared to read like a diary. This is the story of uh my progression
into becoming a serial killer. and it documented luring people off the internet. His first victim was a man
named Jill Tetro. I saw this uh lady. She had blonde hair. She's about 56. She she was very
attractive looking. And what was her name? Her name was Sheena. Sheena. Yeah. I messaged her. She messaged me
back. How about we go to dinner in a movie? I thought that was a great idea. She wouldn't give me the uh house
number, but she just sent me really really good directions on how to get there. He thought, right, what's the
worst that could happen? [Music] [Music] It would appear that I'm unique in the world. There is no key, no root cause.
If there's no school, if I really were capable of premeditated murder, normal, healthy, welladjusted, 30 old men. I
once heard the legend of another worthy victim. wonderful young children and great futures. I dealt with his remains
in a disrespectful manner that traumatized me forever into psychopathic serial killers. My compassion, I quickly
grew to resent and hate this man. These are the words of Mark Twitchell written to author Steve Liuan.
It is what it is and I am what I am. For the first time on television, Liuan is revealing the contents of Twitch's
letters. It's a rare look inside the mind of a killer. Nobody would side with Dexter Morgan if he went around
slaughtering school teachers and mail carriers on a whim. Police say Twitchell was fascinated by
the fictional character in the hit Showtime series Dexter. I need to kill him. Twitchel'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. To hear how everything happened, it was
like you watching the movies. Edmonton police detective. It's hard to say. I mean,
Bill Clark, but now we have it happening in real life. Jill's Tetro was online on the
plentyfish.com website, which is a a dating site. Tetro, who was 33 at the time, was excited to meet the woman who
called herself Sheena. I was actually late, so I was driving quite fast to get there.
She said, "I'll just leave the garage door open for you." And then you just go in, go through the garage.
I don't think he ever imagined in a million years what would happen to him in that garage.
It was dark. Then I I kind of looked around for the door she told me to go through and that's when somebody came
out and attacked me from behind. Finally looked back and that's when I see this man
with this painted up hockey mask. I just chill down my back. Wow. This is no date.
He's about like 6 foot and and has this black and gold hockey mask all painted up on his face.
The hockey maskwearing man had ordered him to the ground at gunpoint 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. In my head is just
racing like it's like thinking what's going on? What is he going to do? Is he taking another weapon out? Jill decided
he wasn't waiting to find out. I can't do this. I got to fight back. So, I got up and uh ripped the tape off
my eyes. He was stunned that I got up and he started yelling at me to get back down on the ground.
Instead, he grabbed the attacker's gun. 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. That's when I I was ready to
fight. I punched him and I felt really weak. I'm like, "Wow, why was my punch so weak?"
What Jill didn't realize was that he had been weakened by the effects of the stun
baton. And then he starts punching me on the side of the head. Just about then, he came up with a plan.
He grabbed my jacket. I jerked forward to make sure he had a good hold on it. I thought, "That's a perfect time."
That was part of your plan. You're thinking, "Okay, he grabs my jacket." Yeah. And I can get free.
So that's when I slipped out of the jacket, rolled underneath the garage door, and then got up and it worked. And
I tried to run, and all of a sudden, my legs wouldn't work, and I just fell. Boom. Right on the gravel driveway.
That's when he grabbed my legs and he started pulling me back to the garage. So I'm like, "Oh no, what am I going to
do now? I'm dead." Gio was thrown back in the garage, but he surprised himself by rolling out again. This time, Gil
managed to get into his truck. I stuck the key in the ignition and then I just sped away.
When Gil got home, he discovered the profile on the dating site had been deleted, and he did his best to erase
his own memory. Why didn't you go to the police immediately? At first, I was in shock. I said I told
myself I'll do it tomorrow. And tomorrow came and I was um I felt so ashamed that
I got duped. Embarrassed and confused, Gil convinced himself that perhaps it wasn't as
serious as he first thought. I really thought it was a mugging at the time. But just one week later, another man,
Johnny Alteringer, would answer a similar dating ad and disappear. Where is he? What's going on? He
wouldn't do this to us. Gary Alteringer, Johnny's older brother, says the last time anyone heard from him
was on October 10th, 2008 when the 38-year-old left for a date with a woman named Jen.
Not a message, nothing. And then not showing up for work, totally out of character. John was very very very
responsible. And when did you grow concerned? When I received that email and this email was completely out of
character. What did it say? I've met a woman named Jen and I'm going away with her to Costa Rica and I'll
call you at Christmas time. I just thought right away after I had read this, that's got to 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. 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."
You know, he was his red Mazda was missing. He had taken his vehicle. It couldn't be found. So, obviously, that's
what we're going to look for first. Easier to find a car than than a person. Based on the emails and 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 Alteringer had forwarded the directions of where he was going to friends.
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. They learned the garage is rented out to
an individual named Mark Twitchell. Action. Twitchell, then 29 years old, a married
man with a young daughter, had used the garage as a set for a recent movie project.
I'm glad I got the chance to work with you all and I hope you I see you all in the industry. Mark denied knowing
anything about a missing man or a red Mazda and he had no problem with the police wanting to search the garage.
They have a look around and they see some what looks like blood and Mark Twitch's explaining, "Oh no, that's my
movie prop. We did a film about a killing a guy in here and I filmed it all and I've been cleaning it up over
the last couple weeks." There were some things that were, you know, raising your Spidey sense in this
one going, "Yeah, this isn't right. Something going on here. [Music] For detectives in the Edmonton Police
Department, the disappearance of Johnny Alttinger was a mystery in more ways than one.
It's a missing person's case. We don't know what foul plays happened here. We We don't have a body. Uh we don't even
know if we have a crime. Their only lead was Mark Twitchel's film set garage voluntarily. The amateur
filmmaker came down to the Edmonton Police Station to speak with detectives. All
does that name ring a bell to you or mean anything to you? No. Never heard it before.
No. Mark appeared to be eager to help. He had no history of violence and was hardly a suspect.
Action. In fact, he seemed guilty of nothing more than wanting to brag about his film
career. I'm working on a comedy right now, which is a it's actually a full-blown feature
that's actually going to have a decent budget in the neighborhood of about 3.5 million.
Mark Twitchell's first film project, a Star Wars fan film, had received some media buzz back in 2007. Word has gotten
around that I'm making a $100 million movie for 60 grand. And uh some production and directing jobs have
already come my way. But the police were more interested in Mark's latest production, a suspense thriller called
House of Cards, where a hockey mass serial killer lures a man to a garage via the internet and
kills him. I mean, it's kind of odd that you're filming that kind of thing. And we end up going to that garage
because of a missing person who supposedly went there. That's really freaky, too. And as soon
as they called me on the phone, I get this weird chill. He looked pretty comfortable in the
interview. And when it was done and I watched, I went, "Wow, that guy interviewed well."
Hours later, Mark 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. 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 Alteringer's red Mazda. So
investigators called Mark again and again he voluntarily agreed to answer more questions.
This time Bill Clark conducted the interview. So as you know Mark, we're just here
trying to find John Alinger. Clark listened while Mark told him how he came into possession of a red car, a
detail he failed to mention when he spoke with police earlier. This guy uh taps on my window, you know,
hey buddy, do you want to buy a car? I have shacked up with this really rich lady and she's going to buy me a new
car. So, I'm just looking to unload vine. How much do you have on you? And Mark claimed he bought the red Mazda for
just $40 and that it was parked at a friend's house. So, what are you thinking when you hear
that? That he purchased a car for $40. I just thought that's unbelievable. That's just right away I'm thinking 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. 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. Why? But it was only a hunch. Clark had no
hard evidence against Mark. Police began digging deeper into his background. They
were interested in speaking with anyone who had worked on House of Cards, where actor Chris Huard's character meets an
untimely bloody end in the film. My character was killed with the samurai sword. As I 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 the weapons,
that was my first time. When I saw that they were real, I thought, "This is off." I'm think, "Why didn't I tell
somebody where I am?" Huard left the garage film set unharmed but rattled. And his unease only escalated when
police asked him about that allegedly fake movie blood they spotted in the garage.
How much of the blood splatter on the wall was from your filming? I said none of the blood splatter was from a
and then in a search of Twitchel's belongings, police found his laptop. They pulled off a hard drive a deleted
file titled SK Confessions. SK confessions. Police believe SK was shorthand for serial killer.
One of the first lines it says, "I am 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. I plunged the knife deep into his neck.
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 Twitchel's confession of
murder [Music] [Music] It just doesn't make sense. Where there's smoke, there's fire.
2 weeks after the disappearance of Johnny Alteringer at a garage film set, police had sharpened their focus on
filmmaker Mark Twitchell. Police cameras were rolling as a forensics team processed Twitchel's family car and the
garage he rented. And a few miles away, detectives have been at the Twitchel home where they
found Jess Twitchell, Mark's unsuspecting wife of two years. What I said was, "We're investigating a missing
person's. I believe your husband's got something to do with it, and it's 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 Twitchel marriage was already fractured. They had
been living in basically sleeping in separate bedrooms. She was basically living on the main floor. He was living
in the basement. So there was obviously troubles in paradise there and we knew that
Twitchell had been having an affair with an old girlfriend and lying to his wife
about having a job. He found out that 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 and went
through great lengths to bring my wife over to the comfortable belief I wasn't cheating on her.
It was uh basically a almost like a movie script. But what was real and what was fiction?
The closer police look, the more the lines blurred. Police discovered Twitchel spent
countless hours making elaborate Halloween costumes. It's almost like at times Mark Twitchel
lives in a fantasy world. But it was Twitchel'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
Twitchel status. He talked a lot about uh how he loved the show Dexter. I need to kill him.
Twitchel even posed as Dexter Morgan on Facebook. 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. I am a huge fan of this Showtime show,
Dexter. So, I thought, "Oh, well, you know, I'll be friends with him." Eventually, Twitchel revealed his true
identity. He was a filmmaker. We are rolling and he was working on a a new thing
called House of Cards. Camera's rolling. Renee was intrigued. After all, she was
an aspiring writer and her friendship with a movie maker could open doors. I thought it was going to be like a
working relationship, a working friendship. Um, you know, we had a lot in common.
I mean, you spoke to him a couple of times a day online. Couple of times a day. Was it flirtatious?
Oh, yeah. Absolutely. Their email exchanges soon became dark. It was shortly before Johnny Alteringer
disappeared. 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. 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? How do you get away with it?
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 uh dump her out in the middle of Lake Erie.
But then she began to wonder. He said over the weekend he did something and he liked it.
I crossed the line and I did something and I liked it. And what did you take that to mean?
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.
There's an enormous missing person, possible homicide investigation going on centralized around a location I've been
renting 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 Twitchel had underestimated the police. He thought he was way smarter than the
police. Uh, 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, Twitchel possessing Altering's car, the
SK Confessions document, and his Dexter obsession, investigators finally had hard evidence.
They found Alteringer's blood in Twitchel's trunk. When we got the word that uh the DNA
matched, we briefed our tactical team, our our arrest team, and we had officers ready to make the arrest.
On Halloween morning 2008, while Twitchel was putting the finishing touches on his Halloween costume at his
parents' home, police were busy laying a trap. We got an undercover operator to work
the internet and pretend he was going to 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, 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 uh
taste of his own medicine, I guess. Back at the station, Detective Clark and Twitchell came face to face in the
interrogation room once again. As I told you that night, I knew that you were involved in the disappearance at that
time of Johnny Alteringer. That's changed slightly. I now know that you killed John Alteringer.
3 weeks after Alteringer's disappearance, police charged Twitchel with firstdegree murder. The once
talkative movie director barely uttered a line. You didn't get much of a reaction, did
you? No, he's uh well, he knows not to say anything. Talking to his lawyers, he's not going to admit to anything.
He didn't have to. Es 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 red
I thrusted into his gut. His reaction was pure Hollywood. We do believe as investigators that the account written
by Mark Twitchell in that SK confessions is exactly what he did to John Alteringer.
By now, Renee had called the 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. It was just a
huge piece of evidence because 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 Detective Bill Clark knew his next move
was finding the alleged victim who had escaped from Mark Twitchel's garage. 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 Twitchel's home. 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.
We have some details on this male victim who was attacked, and we would like him
to come forward. Gil Tetro was at home oblivious to the horror he had escaped when a friend told
him to watch the news. 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. 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 Gil heard next came as an even greater shock. Another man had been
lured to the same garage and met a gruesome end. We have not found John Altinger's body.
And what were you thinking when you when you heard this? 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 gonna kill me. I'm like, "Wow, I I have to go forward now. I have
to come forward." Exactly one month after he was attacked, Gil Tetro walked into the Edmonton
Police Department and told police his incredible story. I was all off balance. I couldn't run. I
fell down on the the gravel driveway and uh basically crawling. So he dragged me
back to the garage. Jill's story matched nearly word for word what was in SK Confessions. I
grabbed him by the leg as if to drag him back into the garage caveman style. So I know that this diary we have is
true. After this all happened, I realized how lucky I was. 7 days after Gil was attacked, police say Twitchell wasn't
going to make the same mistake twice. How did he kill uh John? We know that he lured him to the garage
in the same way he lured Jill's tetro. And then in this case, because he learned from Jules that the taser didn't
work, he hit him over the head with a lead pipe. Following the narrative, police believe Alteringer was then
stabbed and dismembered on a makeshift autopsy table. What was the most damning piece of
evidence that you discovered? We had uh, you know, lumininal test 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 Alteringer'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. Ultimately, Mark Twitchell drove around with it. According to the SK Confessions
document, he even talked about driving around with them and pulling up beside people at red lights and looking at them
and thinking that they don't know I have a dead body in the trunk of my car. But where was Johnny Alttinger's body?
SK Confessions describe the killer finally choosing a sewer to dump the remains. But that's where the pages
stopped. It was a story without an ending. 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 him, "Look, we found Johnny."
Detective Clark hoped Twitchell would provide the final chapter. I'm going to go get the car ready. We're
going to take a drive. You guys were driving around and there was a camera trained on him in the back
of the police car. Tell me about that. 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 cuz we had no idea where where Johnny's remains were at that time.
So in order to finish the movie, we find the body, take it back to the people, family. Done. Movie's over. You write it
all down. Detective Clark was relentless, taking Twitchel on a tour of his old neighborhood. And we first drove to his
parents house where he had been staying. We actually demanded that he tell us he
wouldn't. Look familiar, Mark? Are we parked right on top of the sewer where you dumped the
body? Next stop, the scene of the crime. So, here we are back at the killing garage, the Dexter garage.
Bring back any memories? You want to tell us where the body is now? We'll get this over with.
But Switch will remain silent. So police kept searching on their own, looking in
sewer after sewer. So all these manhole covers were pulled off in this alley. So anytime I'd see
one, I always had 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 Alinger disappeared, Twitchel,
while awaiting trial, broke his silence and gave the police a map. just up here on the left. It's about a
block south of his parents' house. Investigators followed it to an alleyway just a half block away from where they
had stopped the search. And he had marked an X. X marks a spot. It took us right to this uh sewer cover
here. We could see what looked like pieces of human torso uh down there. [Music]
In March of 2011, Mark Twitchell went on trial for the murder of Johnny Alttinger. Prosecutors called Gil Tetro
to testify and to prove that what Twitchel described in SK Confessions was not a work of fiction, but an account of
what had actually happened. 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
Liibuan, a college professor and did an investigative journalist was covering the trial for the Edmonton Journal and
went on to write a book, The Devil Cinema, about the case. Mark Twitchell testified that this was
all a big misunderstanding and he had killed Johnny in self-defense. Twitchell claimed that Alteringer's death was
nothing more than a publicity stunt gone horribly arry. 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 Alteringer became enraged at being tricked and he accidentally killed
him in self-defense. 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 5 hours to find Mark Twitchell guilty. He was
sentenced to 25 years to life. But for Liibuan, there were still so many questions.
So the motive is the mystery, the why did he do this? What is Mark Twitchell's psyche? What led to this happening?
questions liab might be answered when he got a call out of the blue from Mark Twitchell himself. He just said straight
out, "If you're going to be writing a book about me, you might as well come straight to the source."
What do you think Mark Twitchel's motive was? See the evidence presented at trial
and more at 48 hours.com. [Music] The first time I met him, he actually had me laughing. He's very charismatic.
Mark Twitchell was nothing like author Steve Liibu and expected. Has very much that salesman slick
behavior. He knows how to put it on to get people to like him. Twitchel began writing to Liibuan before
he was even convicted in 2011. Over the course of almost 3 years, they exchanged
dozens of letters. I learned really quickly that he preferred to talk through writing.
These weren't ramblings of a crazy man. There was actually some substance in these letters.
Yes, absolutely. So, he's not he's not crazy. He is he is lucid. At first, Lilibuan didn't want to push
Twitchel away with too many probing questions about his crimes. I asked him a lot of softball questions just about
who he was, his family, his upbringing, all that kind of background detail. He was newly married and a new father. So,
he was 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, Twitchel clung to his
defense that he had no choice but to kill Johnny Alttinger and then dismember him. He writes, "I killed Joanie
Altinger in a horrific accident of self-defense." After cursily shoving aside my human
sensibilities, I dealt with his remains in the disrespectful manner that traumatized me forever. He still is
adamant that this was not a planned and deliberate murder. And to be frank, he's
he's wrong. Liibu and 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. Mark Twitchell wrote to me quite extensively about his interest in Dexter.
Dexter on his mind, Twitchell drew this portrait of Michael C. Hall, the actor who plays him. And to Lil Buan's
surprise, even behind bars, Twitchell was able to feed his obsessions. Previously on Dexter,
Mark Twitch had actually been granted access to finish watching the series while he was incarcerated.
In 2012, Dexter star Michael Se Hall was asked about Mark Twitchel on a Canadian
radio program. It's horrifying to entertain the notion that something you did inspired that.
Twitchel's response to Hall's comments was to downplay his fascination with the Dexter character.
So, he wrote to me, "As you're aware, Dexter has almost nothing to do with my case."
Throughout their correspondence, Liabuan continued to grapple with what drove Twitchel.
And then Twitchel told him, "There is no key, no root cause. There's no school bully or impressional gory
movies or Showtime television series to point the finger at. It is what it is and I am what I am.
He's a depraved individual and he knows that. Retired FBI criminal profiler Julia
Calli 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 Twitchel tick. I think he identified with Dexter to some degree. I
think he's different than Dexter. He's not killing bad guys. He's killing very innocent, good people, living productive
lives. And while he's technically not a serial killer, he was headed in that direction if they hadn't have caught
him. Calli believes Twitchell took pleasure in planning and executing his crimes as
if they were romantic trrists. I think the primary motivation was sexual. Sexual.
Yes. And he's targeting men that perhaps he would be interested in having a date
with. It's a combination of sexual motive and a thrill killing. He's 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. He said, "I wanted the weapon used for the deed itself to be simple, elegant, and beautiful."
And in a strange twist, Twitchel's been able to feed that obsession, too. In 2017, he was allowed to join an online
dating website for inmates, which, you know, I find quite surprising considering 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 Twitchel's garage, Gil Tetro, continues to be haunted by the experience.
We caught up with him recently. I still think about the paired up hockey mask. I still think about the stun gun
and the fight for my life. Mark Twitchell cannot be rehabilitated. This is who he is.
Action. And for Mark Twitchell, the aspiring filmmaker, there may be one final plot
twist. Author Steve Liibuan sold the rights to his book, The Devil Cinema, to a film company. Twitchel's story may be
coming to the big screen. A son with secrets. He just lied to everybody. His parents vanish. You know, cars go
off the road. Things happen. What happened to the Haldersons? Not making any sense. And it's taking
weirder and weirder turns. Nobody saw this coming. 48 hours crime time double feature
continues next on CBS. [Music]

Inside the mind of murderer Mark Twitchell — letters from the man police say wanted to be like fictional serial killer Dexter. "48 Hours" contributor Troy Roberts reports. Watch more full episodes of "48 Hours" on Pluto TV.

True crime. Real justice. "48 Hours" investigates the most intriguing crime and justice cases that touch on all areas of the human experience including greed and passion. "48 Hours," which premiered in 1988, has developed a rich history of original reporting and impact journalism that has helped exonerate wrongly convicted people, caused cold cases to be reopened and solved, and along the way changed lives.

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Brief Summary

Mark Twitchell, the "Dexter Killer," lured victims inspired by the show, leading to his arrest and trial for murder.

Key points

The Unusual Case of Mark Twitchell. Retired FBI agent Julia Cowie discusses the bizarre case of Mark Twitchell, an aspiring filmmaker turned serial killer.
The Kill Room. Twitchell set up a kill room reminiscent of the fictional Dexter Morgan's methods.
The Disappearance of Johnny Alteringer. Johnny Alteringer vanished after a date arranged online, leading to a chilling investigation.
The Shocking Confession. Investigators found hard evidence linking Twitchell to the murder of Johnny Alteringer.
Twitchell's Arrest. On Halloween 2008, police arrested Mark Twitchell while he was preparing his costume.
Trial and Conviction. Mark Twitchell was found guilty of first-degree murder after a brief jury deliberation.

Episode highlights

Episode quotes

It is what it is and I am what I am.

Mark Twitchell's reflection on his identity.

4:24WatchJul 8, 2025

Tension

85/ 100High tension

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