Original subtitles

[reporter] A squad car still guards the home where the bodies of

Richard and Janet Sweet were found by family coming Sunday

for a Mother's Day celebration.

Police set out on a statewide manhunt for the teen since

Sunday when the bodies were first discovered in the home

on Deann Drive.

We're hoping that with the hard work that

everybody's doing, the cooperation among agencies,

that we will have a resolve to this soon.

[reporter] Off camera, neighbors described the teen as

troubled, saying he gave his grandparents a hard time.

The thing inside of me, it's like...

the appetite -- it's like a wolf that's...

feeling... the hunger.

[reporter] Monday night, police found Sweet walking on

railroad tracks in northeast Cedar Rapids,

ending a 36-hour statewide manhunt.

Hours before his capture, police issued a warrant for

the teen's arrest.

Court documents describe phone calls where Sweet admitted

to three people that he killed his grandparents.

The shocking aspect of the first impression is just

his tone, his demeanor.

The glibness, there's a certain lightness to it.

You know, just lack of any gravity.

Like, if you kind of came into this conversation,

you know, not necessarily knowing that it was between

a suspect in a police officer,

I don't think anybody would have any sense that he just

brutally killed his grandparents.

He does present as very theatrical,

and there is a real shallow component to

his emotional expression.

It makes you question, is any of this genuine?

And even though Sweet is painting this picture that

he's a victim of the stress

and his grandfather being a jerk,

what we know from the records is that, actually,

police have been to their house 18 times

for domestic disturbances.

And these were the product of Isaiah threatening

his grandparents or otherwise being behaviorally disruptive.

But in this interview, he's trying to engage in

impression management so that he doesn't seem like a monster.

[Dr. De La Torre] He wanted to live his life at the expense of

his grandfather's life. This was more about hate.

This was more about an offense that Sweet had felt

he had received from his grandfather.

I don't think he ever truly loved them.

I think what they were simply trying to do is just instill

some kind of humanity into someone who clearly didn't

want that. That's not what he wanted.

He wanted to go out and party.

What we see now is the 17-year-old

version of the psychopath.

Sweet is just that burgeoning psychopath who is still trying

to figure things out.

Who is he going to be in his psychopathy?

But what we know is that physical violence

is going to be the thing that he's going to use

if you don't give him what he wants.

Do I think he actually held the bat up

to his grandfather's head and then decided not to?

No, I don't think that happened.

Sometimes the story has to be

about building yourself up to yourself.

Sometimes it's not about building yourself up to

whoever's listening.

It's about getting your narcissism up.

It's about getting your arousal up.

It's about saying these things to say, "Hey, I could have done

all of this, but this is the thing that I did."

The bravado that you need in order to venture into

psychopathy is one in which you have to demonstrate

your own willingness to engage in violent acts and escalate

violent acts and fantasize about violent acts.

And I think that's what we're seeing here with Sweet.

It's hard to imagine a more dehumanizing description of

what he did to his grandparents than what we see here.

You almost get the sense that he's bragging

about some of this.

If anything, he seems to get a little activated as

he's discussing it. At one point, he got up.

He was animated.

It was as if he was telling someone about a scene from

a horror movie rather than the actual scene from

what he had just committed.

That level of emotional detachment from this crime is

really stunning, and I would file that away as

a red flag for psychopathic behavior and traits.

[Dr. Saraiya] Having the attention,

I think he is enjoying that.

You know, "These detectives are listening to me.

"They're adults.

You know, they're taking me seriously."

No stress. No problem with his appetite.

As a psychopath, he does not have the empathy,

the guilt, the remorse, any of that feeling to connect it.

It's all intellectual. It's all up here.

And he's inexperienced.

Remember, at this age, he doesn't have a lot of

precedent to base his decisions on.

So he's just kind of going with his natural reactions,

which are emotionless and very in-the-moment.

And, you know, he's hungry

and this is what he feels like eating.

And that is undiminished by anything that's happened before

and the prospects of what's going to happen later.

So it's not even Isaiah's idea to engage in

the nicotine poisoning.

All of this is just, how can I prove myself to other people?

How can I prove myself to...

my friends? How can I prove myself

to the world that I'm big and bad?

And so everything that you think of when it comes to

Isaiah Sweet is still so nebulous.

It's not crystallized.

He's not -- he's not a formed psychopath as of yet.

He's still very juvenile in his thinking,

so heavily influenced by the thoughts

and ideas of other people.

It's not uncommon for children to want to buck the authority

of their parents, but this is taking it five steps too far.

Brandon Ahlers carries no more valence than the grandparents,

like we think about, like, oh,

this was his accomplice, his friend.

He's just another character to Mr. Sweet, so I don't know that

I would insert this idea that he really cared what

Mr. Ahlers thought.

He doesn't have that emotional line connecting things.

There's that psychopathic instinct of, like,

kind of pausing to think, how am I supposed to be behaving here?

Like, how would a quote-unquote normal person answer

these questions and behave in this situation?

So I think the watch is an interesting component that

just, again, illustrates some of his grandiosity, some of

his callousness, some of just the fact that

he's not taking this very seriously.

The conversation then shifts to his mother, and he states that

she's the only one that he hasn't told about this.

He's just killed his mother's parents, and you don't get

the sense that there's any emotional attachment not only

to his grandparents, but even to his mother,

who he also just violated.

The comment, "I know everything,"

I think sums up a lot of Isaiah Sweet's

presentation and how he seems to perceive himself.

He's grandiose, and believes, you know,

from the very beginning of the interview when he tells

the investigators how intelligent he is,

now here we are, fast forward,

later in the interview where he's saying,

"Look, I know how it works -- when you commit

a felony, you can get my cell records."

That grandiosity has seeped throughout the interview

in many points.

He's very proud of this knowledge,

but at the same time, the reality is

this knowledge is not particularly sophisticated.

The unusual detail is the fact that he, you know,

escalated the violence relatively quickly.

He had the obstacle.

He made a decision, I'm getting rid of the obstacle.

And now he's already planning his life in jail.

You know, I just want to sleep and work out and read books.

I mean, I think it was that control aspect.

Like, he understands where he's headed, and he's gonna make

it seem like, you know, this is just fine with him.

So there's an aspect of it of like, you know,

this was all according to plan.