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AUTOMATED VOICE: Thursday 2:19 a.m.

MAN: Minutes before she was kidnapped,

Morton used a cell phone to report

someone had just rear-ended her -- police found her car

running, her purse inside,

but they did not find Morton.

[theme music playing]

MAN: There's this thing inside of me, it's like...

the appetite.

It's like a wolf that's...

filling...the hunger.

♪♪

MAN: Amanda's family contacted news media Thursday morning

and gave them Amanda's picture.

Investigators got their break when a motel owner in

Camden County saw her picture on

the five o'clock news and called police.

He said Amanda and a man in a pickup checked into his motel.

That led police to St. Clair County,

to the home of David Zink.

BERRILL: He can play the easygoing nice guy.

He uses that kind of calm, cool persona to move

his plans along and seems to do so with pretty good success.

SAHNI: Amanda just happened to be in

the wrong place at the wrong time.

I have no doubt that he lulled her

into going with him, because he was charming.

We, as humans, are socialized to believe that people who

are humorous are likeable, and people who are likable

are trustworthy.

So it's a really unfortunate reality that

he was able to exploit as a psychopath

that assumption we make as humans.

DERIGHT: He is not perceiving people as other human beings.

He's seeing them as objects, in this case,

that are in his way -- to me,

the Zink case is all about self-preservation.

He's gonna do whatever it takes

to preserve himself being out of prison.

Assuming this did actually happen,

it gives you the sense that he was not in any way afraid.

He was not in any way unsure about what he was doing.

He was making jokes with the cashier.

He's self-assured, he keeps his cool,

he's got the persona down pat of being, you know, like a good

old boy, and everything is under control,

and that's -- that is spooky.

She's in the office with him, which I find more incredible.

Like, here's this girl, and she doesn't flip out

and say, "Call the police."

So she obviously, on some level, must have

trusted him or didn't see him as a threat.

This just really illustrates how he manipulated her

or, you know, lied to her.

WOMAN: Little did she know, he was a killer.

Zink kidnapped her,

took her to a motel near Camdenton, where he raped her.

He's a psychopath who is lying his way through

this portion of the interrogation.

Zink's DNA was found on Amanda's body.

There is no doubt that there

was some sort of sexual interaction.

BERRILL: It's a little odd -- killing someone's okay,

but don't think about me as a rapist.

There are a lot of crimes you can commit to wind you up

in jail, but sex crimes are seen as sort of the low man on

the totem pole, because sex crimes make you

a target in jail.

If you're a rapist, everyone will say,

"Well, I have a sister or a wife or a mother,

so you're a piece of garbage," and if it's a kid, forget it.

They emerge in prison, at least, as likely targets for sexual

abuse themselves, and he doesn't want to be seen that way.

Zink has a strange disconnect in his thought process

right now, because on the one hand,

he's saying he has no intention of going back

to an incarcerated life.

But on the other hand, he's sort of giving into

the simplest, most obvious solution,

which is also the most ridiculous,

the most anti-social, and the most violent.

But for Zink, it isn't as much of a leap.

He has a problem to solve, and this is a logical solution.

Zink underwent psychological evaluations as part of

his court cases, and they really

give you a sense of how his psychopathy manifested

from an early age.

The report reads, "Zink was afraid of his mother,

"who suffered from depression and was impatient,

"nervous, and irritable.

"She was very harsh with him and often yelled at him,

"grabbed him, and talked down to him.

"She provided little guidance or discipline.

"She would get drunk a lot and would get angry.

Zink hid from her."

And here's what Zink says about his father.

The same report reads, "When Zink was four, his father

"was involuntarily committed to a mental hospital for

"several months -- his father often talked of

"suicide or engaged in suicidal behaviors,

"even in front of Zink and his two sisters.

Zink saw his father take a gun and threaten to shoot himself."

I don't think they're necessarily modeling

psychopathy here,

but they are modeling violent behavior.

So he has whatever genetics are there.

He has this upbringing where he's neglected.

This is the recipe for psychopathy here.

BERRILL: If you're talking nature versus nurture,

I really do think that,

you know, there is some temperament

that you're born with.

For example, if you're a high risk taker, and you're fearless,

maybe you become a firefighter,

or, depending on the environment

you grow up in, you become a bully,

or you become someone that engages in criminal behavior,

but the environment will lead you down a path to

acting that temperament out in some fashion.

We know he's a risk taker.

So if you grow up in a house where there is violence,

it does set the tone, perhaps, for becoming

the kind of person he became.

BERRILL: There's some amusement he takes

in the fact that she's not getting it.

She's essentially being escorted to her death.

He's not telling her the truth about what's gonna happen.

It's all sadistic, uh,

but he doesn't want her to panic,

so he's staying cool.

DERIGHT: To him, it's extremely logical that she

should be using common sense at this point,

when nothing about this invokes

the idea of common sense -- to Zink,

all of these pieces do connect in a very cohesive way,

but they don't.

It's part of the narcissistic tendency to feel like you have

everything under control and figured out.

WOMAN: About six hours later,

at 4 in the morning, investigators recovered Amanda's

body from a shallow grave in this cemetery.

MAN: She'd been strangled and stabbed.

BERRILL: His description of the murder is highly sanitized.

The fact that they found dirt in her mouth or seminal fluid

in her anus would suggest that, uh, there was

a deeper level of psychopathology taking place

that he cared to discuss.

In looking at the court records

and psychological evaluations that were available on Zink,

here's an excerpt that gives us some of that information.

"By the time he was 10, Zink was placed in foster care.

"Within a few weeks, Zink ran away.

"Around that time, his foster mother found

him making a noose out of a rope."

He had an emerging obsession and fixation or focus on

strangulation from a very, very young age.

Clearly, there was a willingness to

start to skirt the idea of death,

the idea of violence,

the idea of strangulation.

BERRILL: The fact that he had rope in his car,

I don't know if that's just a coincidence.

You don't have to tie a dead body to a tree,

but you do have to tie a live body to a tree

so that they can't struggle.

It raises, I guess, deeper concerns

about how savage he really is.

DERIGHT: We'll never know if those were actually

her last words, but in one way or another,

he wanted you to know that there is some connection with

his mom in why he's doing this, too.

The connections between Zink and his mom were

really apparent in the court records, as well.

The court records say, "Although the foster family

"wanted to adopt him, he always

"fantasized about going back home -- at age 14,

"Zink asked to move home, but his mother refused,

devastating him."

The thing that really pops out to me here is this

element of maternal rejection, which in the psychopathy

literature, is very prominent.

And this is not an everyday maternal rejection.

This is mom gave him up,

but it is not inevitable that anyone who is rejected

by their mother is going to be a psychopath.

It is one piece of the very,

very complicated puzzle that goes into creating a psychopath,

and it is not an excuse for

what he turned into and what he did.

DERIGHT: This is the kind of statement that

gives you this icky feeling that you're --

you just shouldn't be hearing something like this.

We see that he was torturing her, he was beating her.

He was playing with her as an object,

and it takes it to a whole other level.

SAHNI: And unlike some other psychopaths,

he doesn't really even make an attempt to pretend

that he feels bad.

He doesn't try to pretend that he has emotions

or that he's even really bothered or disturbed by it.

SAHNI: He's not panicked. This is just a normal day,

like it's no big deal.

And that really I think sums up a lot of how Zink,

as a psychopath, sees his crimes.

He's just really not broken up by them.

One thing that's really notable from Zink's childhood is

that he seemed to have a pretty severe case of meningitis,

and the results of his PET scan were consistent with some

of the brain abnormalities that

we know about psychopaths in the literature.

For example, he had less activation in the amygdala

and the cingulate, both of which

are very important areas in the brain involved in

fear and emotional response.

So the fact that these areas are under-activated

in psychopaths and in Zink is not surprising.

He is not afraid at all of the consequences.

After his arrest, Zink exchanged letters

with a local TV news journalist.

Uh, here are some excerpts from it.

"I've secretly always wanted to be a serial killer.

"Your preconceived idea

"that this is a crime motivated by some type of

"sexual perversion -- you don't even come close.

"There's no sex in the world that can

"give you a pleasure of taking a life,

"watching their eyes, and knowing that I have

"the power to give or take that life.

"I hope that you would just put this letter in the trash.

"Nothing good can come from selling death.

Have a good day, David Zink."

It's almost his manifesto in a way -- he wants to control

the narrative and say, "Hey,

put me on TV, and this is the story I want you to tell."

BERRILL: But you heard none of that kind of talk during

his interview, nothing even remotely like that.

He's kind of a liar, and he's playing games to sidestep

the whole notion that he's driven

by perverse violent sexual fantasies.

There seemed to be a multitude of risk factors here,

where he has these biological variants

and his tumultuous upbringing that all come together here

and really create a recipe for a psychopath.

Mr. Zink, would you please rise?

We, the jury, having found the defendant,

David Stanley Zink guilty of murder in the first degree of

Amanda L. Morton,

now assess and declare the punishment at death.

MAN: The Morton family says they will now move on

and try to come to grips with what's happened.

What will you tell Amanda in your prayers tonight?

We got it for you, baby.

As well as we can do, we got justice for you.