Original subtitles

This was definitely a frenzy, this...

Essentially, the person went berserk.

A vicious slaying.

People were terrified.

People need a reason that bad things happen.

A dark mystery with multiple suspects.

They were sisters, but there was no sisterly love.

I'm just thinking, "what do I do if he freaks out?"

There was a lot of hate, there was a lot of discontent

within that family circle.

The truth will be revealed.

What stood out to me is this crime scene is...

There was no rhyme or reason, it just didn't make sense.

If Keith did this, he needs to pay for it.

Every day in North America,

dozens of people are murdered.

The key to solving the toughest of these homicides

lies in the final 24 hours of the victim's life.

To crack the case,

detectives must reconstruct that critical timeline,

the minutes and hours containing evidence

that can help unlock the mystery

and catch the killer.

On the banks of the St. Joseph river

sits niles, Michigan,

a community brimming with civic pride.

So niles is... It's a small town, um,

everybody knows everybody.

It's the kind of community where you could meet

a stranger, and you both know the same person.

And fortunately, we don't have a lot of violent crime here.

If crime happens,

people are more than willing to help you.

People respect police. Yes, sir. No, sir.

Here, people get involved.

But on one cold February afternoon,

something so shocking happens, no one knows what to do.

We received a 911 call from a father who says

that his son and his daughter-in-law

are deceased... He thinks it's a homicide.

I immediately called one of the troopers on a cellphone.

I actually said, "you need to get over here."

The victims are Carolyn and John tarwacki,

two beloved musicians who live with their nephew, kelan.

John and Carolyn met late in life.

They met online.

They were just in a great place in

their life, because they had found each other,

they were happily married.

Carolyn was a good soul, as I put it.

She used to pick up,

old music instruments, and she would repair them

and try to help kids who couldn't afford an instrument.

And John was a Navy veteran.

Hard workers, both of them.

Tasked with investigating their deaths,

are detectives fabian Suarez of the Michigan state police

and local detective Kristen daly,

who has lived in this community for 20 years.

When we arrived there, that's when the lightbulb went

off for me that, these... These people that I know.

My sister-in-law was very

good friends with Carolyn in high school,

so there was an immediate connection there,

and I felt a lot more responsibility.

Detectives begin analyzing the crime scene,

trying to imagine what might have taken place.

We walk into the foyer area of the house.

Obviously, we take a quick moment,

we stand, we scan.

I can see John tarwacki.

He's got stab wounds on his back.

We walk over to the right, there's a living room.

We look in there, and we see Carolyn.

We look to the left, there's a bathroom there.

One of the first things I noticed was there's a towel

on the floor with hair clippings,

and there's a razor on the sink, so to me,

that tells me he was shaving his head.

My gut feeling is the killer is confronted by John.

He takes the first shot.

He hits John right in the jaw, he shoots again,

John throws up his arm, and then he turns,

and he... Like he's trying to escape

and he collapses right there.

So now John is out of the picture.

Now the killer can take his... Focus his attention on Carolyn.

At the time that you first looked at her,

it was almost hard to tell exactly what had happened

to her... She had been badly beaten.

Being beaten is usually very, um, very immediate.

It usually dictates that that's somebody that you know

really well and you're really,

really angry at when you see that level of injury and that

level of violence visited upon somebody.

And later, it was determined that she was both stabbed

and shot,

and that's an extreme level of violence

against the nicest person that you would... literally would

ever meet, made absolutely no sense.

To find out who ruthlessly killed

this loving couple,

police must reconstruct the final 24 hours

of the tarwackis' lives.

The timeline's important in every homicide case.

You have to know where all your players are in any

given moment

to create... either to create an alibi or to break

an alibi, to set your timeline so you can discover,

when was their vulnerability? When did the murder occur?

Investigators start building

John and Carolyn's timeline

by interviewing the person who found them,

John's father.

When I first met John tarwacki, sr.,

obviously her was very distraught.

How else could you be? You just walked in,

you find your son and your daughter-in-law murdered.

He said John and Carolyn had

an 8 A.M. meeting at the high school.

They never showed up. This is not like Carolyn.

She will not miss work.

She will not miss appointments, anything like that.

So the school called quinlan & fabish,

which is where they worked,

and said Carolyn never showed up.

Um, what happened?

John's sister worked for the company, too, so they called

John's father like, "can you go check and see what's going on?"

He, in turn, said he tried calling the house.

He tried calling the cellphones, and nothing happened.

So he decided to get in the car and go knock on the door.

Hoping to flesh out the tarwackis' timeline further,

detectives reach out to Carolyn's mother, Sharon.

Sharon tells me that she talked with

Carolyn on the phone that morning.

She was having some issues with her computer,

so she was just venting some frustration to her mom.

Just a normal touching base with your mom in the morning.

Sharon said there was nothing about that phone call

that made her...

Suspicious.

Detectives pull Sharon's cellphone records

and verify that the call started at 6:10 A.M.

And lasted exactly 12 minutes.

The last time she talks to her mother is 6:22,

um, says goodbye,

not realizing, either one, that it's the last time.

But what happened after she hung up

with her mother is still a mystery.

Knowing that Carolyn was on her computer

that morning gives them something to work with.

Investigators dig into her laptop logs.

Carolyn logged onto the computer at 6:43 A.M.,

and then 7:03, the computer goes dormant, meaning that

there's no longer any interaction, like,

with the keyboard.

Every time you hit a key on any device,

there is a record of that.

And when we see habitual use and ongoing keystrokes and then

a sudden stoppage,

that stoppage point serves as a great start for what happened

next... were they interrupted,

were they pulled away from the computer,

or were they actually murdered at that particular time?

Based on when the computer goes dormant,

Carolyn and John could have been killed any time between

7:03 A.M.

And just before their bodies were found at 12:45 P.M.

The bodies are sent off for autopsy,

and the forensics team starts scouring the house for

potential murder weapons.

We're looking for a knife,

and we're looking for a gun at that point.

We don't know if he used one of kitchen knives.

So we took all the knives

that looked like they could have been used for the murders,

and we sent those to the medical examiner.

As they continue to work their way

through the crime scene, investigators struggle

to come up with a rational theory for the murders.

What stood out to me is this crime scene

is there was no rhyme or reason.

There's no sign of any forced entry whatsoever.

There were valuables laying around.

You could think it was a breaking and entering,

someone had gone in to steal things,

but there was computers, there were laptops, iPads,

cash money laying around.

There was even prescription drugs in the medicine cabinet.

It's not until they make their way to the back of

the house that the first clue into the identity of the killer

reveals itself.

From where we're standing, I can hear a dog going crazy,

and it turns out this is wrigley, a 200-pound master.

The tarwackis had a large dog.

It was ginormous, and it was on the back porch area.

And so in their kitchen, you turned,

and you could either go down in the basement,

or you can go out into a back porch.

Once we get to the back door,

that's when we see footprints.

One set of footprints coming in.

One set of footprints going... coming out.

The footprints showed that somebody had

entered and exited through the back door,

um, which was unusual, because they would

have had to get past that dog,

and that dog was incredibly protective of Carolyn.

So normally, if you are a stranger, and you open

someone's back porch door and you are

greeted by a large mastiff,

you turn around and walk away.

You don't continue to enter the home.

And if it's a stranger, why is

the level of violence on Carolyn so great?

That told US that it was somebody that they knew.

Now, they're hoping this path will

lead them to the killer's doorstep.

You have to work fast.

You gotta work furiously, because if you did it once

and you did it twice,

he can definitely do it again.

Investigators believe that the rage-fueled homicide of

Carolyn and John tarwacki

was an intentional act committed by someone

who knew them.

A crime like this could be really devastating

for a small community.

Word would get out, and it would likely take over

the town within a few hours... There would be

a sense of, "we're all in danger... who's next?"

The only piece of hard evidence investigators have

from the crime scene

is a trail of footprints at the back of the house.

Well, we're pretty sure there's one killer.

There's only one set of footprints.

The stride on the way in was short, like a normal walking

stride, and the straight on the way out was wider,

like a running stride.

It tells US that we know when he approached the house,

he was calm.

And when you left the house, he was agitated

and fleeing, because he had just committed the murders.

Once we get photographs, they are able to get US

a good shoe size and a very good tread pattern.

We could actually look at the picture

and see 12 in the shoe impression,

so we knew it was a size 12 shoe.

And we were able to confirm it was to a route 66 shoe

that was put out by K-Mart but discontinued in 2008.

So this tells me this person

is wearing old shoes that were cheap,

basically, it's not a person that has

a lot of money, that's spending a lot of money.

Using the footprints,

detectives follow the killer's path.

There's the easement.

Nobody really knows... unless you're from that area,

you're not gonna know that easement's there.

It's kind of like a power line easement, so those footprints,

we were able to follow 'em away from the house towards

what's yankee street.

So we do a neighborhood canvass.

It's just as it's called.

We go to every door within a mile

north, west, south, east, every direction,

we knock on the doors.

One of the apartments investigators

canvass belongs to Sherry lintz.

When they knock on her door,

they find her son, Keith, there, as well.

Keith is known to US... He's had many,

many problems with law enforcement.

We know the lintz family.

They just... a lot of... A lot of the family members

have been... unfortunately, been on the wrong side of law.

Detective Suarez consults local detective daly

on whether or not she thinks

Keith could be a person of interest.

I'd heard the name, I knew that he was

in trouble and had been in trouble and had

a criminal history,

but I wasn't familiar with him,

like, being connected to the tarwackis at all.

Investigators question Keith

about whether he knew the tarwackis

and his whereabouts that morning when they were killed.

Keith lintz says he may have walked past the residence

and may have waved at John tarwacki,

but he says "no, he doesn't know 'em."

And Sherry lintz, she's able to confirm to US

that Keith was at the home at 8 A.M.

She said she woke up to go to work

and Keith was asleep on the couch.

She also is able to alibi him,

saying that she actually took Keith the work

on the morning of the homicides.

Satisfied with the lintzes'' accounting of

their whereabouts, police move on,

and it pays off almost right away.

Later on that morning, we found a neighbor

who said, "yep,

"I was outside smoking a cigarette, starting my car up,

and that's when I see a young man running down the alleyway."

She is exact, she is positive that that was,

I believe, at 7:45 A.M.

Those footprints were right by her house, maybe...

30 feet from... from her deck.

She told US, she goes, "you never see anybody

"going through there at this time of the morning.

Nobody ever sees there," and that's what caught

her attention.

This new information is critical.

Assuming the running man is the killer,

investigators are now able to pinpoint when the tarwackis

were murdered.

So as best we can figure, it happened some time

from the time when Carolyn's computer goes dormant

to 7:45, so it's almost a... like

a 40-minute window that this murder

could have occurred in.

It's an unusual time of day

for a double homicide to take place.

It was very brazen... Nobody commits a homicide

when everybody is getting ready to go to work.

You're taking the chance of being seen.

There's too many eyes out, too many people are awake.

Most homicides are gonna involve

the time of darkness

when not many people around or you cannot be seen.

The eyewitness didn't get a good look

at the man's face, but she says he was tall.

She said that she saw a white male,

right around six feet tall, hard to pin down his age,

between 20 and 30 years old, she thought,

wearing a dark...

Whether it was a jacket or a hoodie,

but he had a hood up, and he was running,

um,

past her house out towards the main road.

The description immediately rings a bell

for detective daly.

It sounds like it could be kelan,

Carolyn and John's teenage nephew, who has been

living with them

I was familiar with kelan, um, because his...

His younger brother

had been on the same t-ball team with my son.

So at that point, fabian's like, "well,

you can be the one to go talk to him at the school, then."

Kelan is the son of Carolyn's sister, Katie,

and her husband, David.

Kelan is kind of a combative individual.

One of the reasons he was living with John and Carolyn

was because he didn't get along

with David, and that they had fought

quite a bit.

The fights consisted of a lot of yelling and screaming,

so I'm just thinking, you know,

what do I do if he freaks out, what I do

if he's actually the suspect and he knows, like,

immediately why I'm there?

We know that kelan lives at the house.

He automatically becomes our first suspect,

because he was probably the last people

that saw John and Carolyn alive.

So I had asked Kristen daly to conduct the interview,

because I wanted that female perspective

to talk to him, probably get more information.

We have to determine as quickly as possible,

is he involved? Did he commit the crime?

Does he know who committed the crime?

When I got to the school,

and they brought him out of his classroom,

um, he looked confused.

He knew who I was, but he couldn't really

figure out why I was there.

Kelan's sitting there, and he's looking at US.

I could just see the conflicting play of emotion on his face.

And then fabian tells him exactly why we were there.

He said,

"John and Carolyn, um,

are dead, and we need to talk to you."

And kelan completely melted down.

He just completely had a breakdown right there.

I said, "I need you to go through your morning.

"I need to tell me exactly what you did.

"You need to tell me exactly, as best

you can remember, what time things happened."

He told me that his aunt Carolyn woke

him up in the morning, shortly after six.

He leaves the house about 6:30 in the morning,

and his grandmother lives two doors down

from John and Carolyn.

So at 6:35, he goes to his grandmother's,

talks to her really quick, he grabs some pop

and some beef jerky, he's there for maybe

not even 10 minutes, if that long,

because he catches the bus, then, at 6:45.

Detective daly checks kelan's alibi

with his grandmother, Sharon.

Sharon says she gets off the phone with Carolyn

at 6:22, kelan shows up

within 5, 10 minutes of that phone conversation to

Sharon's home... kelan is calm.

He is clean, so he wouldn't have had time to commit

those murders,

and he would have been a mess, physically.

We follow up with the school

with the times of buses there, cameras in the school.

We know he walked into the school.

We talked to the teachers, we know he walked into

the classroom.

He had a backpack, and there was an empty pop bottle,

like, in the outside of his backpack and also

a bag of jerky,

so that corroborated his story.

Also, there was not a good motive for kelan.

He was in a really good place.

John and Carolyn lost their lives,

but kelan lost his future.

With kelan's whereabouts verified

from 6:22 A.M. to 3:30 P.M., detectives conclude

he couldn't have killed the tarwackis.

According to kelan, he hated living with his mother

and stepfather and wanted to stay with Carolyn

and John permanently.

Once kelan moved out of the home,

his grades picked up, and he really liked it.

Obviously, there was no domestic problems.

There was no fighting, anything like that in the house.

He really liked living there.

Detectives then discover that the tarwackis

had filed for legal guardianship,

so kelan wouldn't have to return

to his parents' home.

In fact, the attorney had served the papers

to kelan's mother, Katie,

just two days before the murders took place.

I knew Katie, so I... I was already familiar

with her temperament.

She, um, doesn't care

what you think about her, and she will

tell you exactly what's on her mind.

She can come across as very aggressive, very combative.

And Katie did not want Carolyn to have guardianship,

and she was angry,

and knowing Katie's personality and knowing that

she could be pretty aggressive,

and just seeing the level of violence visited on Carolyn,

your mind goes to that first person who's angry.

And that circled back to Katie.

The investigation into the brutal double homicide

of Carolyn and John tarwacki

is zeroing in on Carolyn's sister, Katie.

When we interview Katie, basically what she tells US,

growing up, Carolyn was treated better than she was.

They were sisters, but there was no sisterly love.

Katie despised Carolyn.

She tells US, "hey, I didn't kill my sister,

but I'm not gonna miss her."

She told me,

"I've always believed that Carolyn was trying to take

my son because she didn't have kids of her own."

And she really believed this.

So obviously, this raises a flag.

It almost seemed like she didn't care.

A normal person,

you tell them that their brother or sister has died,

it doesn't matter if they fought 20 minutes ago,

they're devastated.

This is their sibling. This is somebody they love.

And she didn't act like your normal...

Sibling to a victim of a horrendous crime.

She was a little detached.

When people don't react as expected

in a police interview, it immediately throws up

a red flag... Why are they acting this way?

Are they potentially involved in this crime?

Um, do they dislike, you know,

a person enough to commit an act of violence?

And in this case, you're wondering, you know,

could this sister have engaged in something violent

towards this couple?

But some things just don't add up with this theory.

The eyewitness said she saw a man between 20

and 30 years old fleeing the scene,

not a 43-year-old woman,

and she said this happened at 7:45 A.M.

Katie actually lived pretty much next door to me.

She is a bus driver for this same school district,

and she drove the bus past my house every morning.

So we were able to confirm with the bus garage that yes,

Katie showed up to work,

she came on time, and she was driving her bus,

and there just wasn't time during a bus route for

her to stop of the house and commit this murder.

Detectives consider a different theory.

I know that she didn't commit this... the homicide,

but maybe the husband decided to do it.

Through police reports,

we know that David drank, we believe he had

a drinking problem.

We know that there's a lot of, you know,

domestic violence in that home.

There was a lot of hate.

There was a lot of discontent within that family circle.

So if you want to keep your wife happy,

you want to keep your family happy,

you're gonna want to do something to help her.

David was quiet to Katie's, you know, more bombastic,

volatile personality, but we had...

Nobody had any doubt that if she'd asked him to do this,

that he would have done that for her.

With David now in their cross hairs,

detectives put the timeline to the test to determine

where he was when the tarwackis were killed.

I believe, from the timeline we built up,

we know that the morning of the homicides,

David had to take the kids to the babysitters.

He says he was there at 7:30 A.M.

Dropping the kids off.

We go to the babysitter,

and we were able to substantiate his whereabouts.

He works in south bend,

so it takes him almost 20 minutes to get to work.

He started work at 8 A.M.

We follow up on his work.

We know that at that work, they actually have palm scanners

to get into the building.

We know that he put his palm there, that he scanned

his palm, and we know that he was at work,

So there was no way that he would

have been the killer, that he was involved.

Having eliminated all three of the people

closest to the tarwackis from the suspect pool,

detectives are stumped.

There are so many things about this case that...

That didn't flow

from a normal investigative standpoint.

We were still really focused, at their point, on

this is somebody that they knew,

somebody that was angry with them,

and we had talked to everybody that we knew that

knew John and Carolyn, um, we talked to John's,

you know, ex-wives.

We dug deep into his past trying to find a motive,

and just nothing was panning out.

Everything was coming up a dead end.

Investigators are forced to consider

whether the murders may have been

more random than they first appeared.

People were terrified.

People need a reason that bad things happen.

When there's no reason that something bad has happened,

then everybody thinks...

Then that can be me,

and that freaks people out, obviously.

We all like to believe that if we just do

the right thing at the right time,

then we're all safe.

But that's not clearly how the world works.

That was the first time that I ever

had trouble sleeping after a case.

It was awful.

It was awful, because it was unsolved,

and...

Just no... no idea at that point.

And the other thing that haunts you is

did you miss something?

As it turns out, they did.

I received a call from the mother, Sharon mcknight,

who was cleaning out the house to sell.

She is cleaning out the refrigerator,

thawing out the freezer, and as she's removing items,

she says she found... She found a bloody knife.

I was actually here at work... I immediately respond to

the location along with one of my troopers.

Sure enough, there's a bloody knife in the freezer.

Investigators have just discovered that they missed

a key piece of evidence

while processing the murder scene of Carolyn

and John tarwacki... A bloody knife.

The sickness feeling that goes over use like, "wow,

how did we miss it?"

We missed it... I mean, I'm the lead investigator.

I have to take responsibility for everything that goes wrong.

So, yeah, it's my responsibly

to make sure everything was done.

It wasn't done properly.

The knife is processed, DNA shows that

it is Carolyn and it is John's blood on the knife,

but unfortunately, there is no third party.

We were hoping maybe to find DNA from our suspect

that could be identified, but there was not.

Having hit yet another roadblock,

the case goes cold.

Then, 2.5 years later, detective Suarez receives

a call that breathes new life into the investigation.

Patricia wilds was a local young lady.

She had a run-in with a local police officer.

She was stopped, she was arrested, I believe,

for driving with a license suspended.

When they brought her in and they booked her,

she told 'em,

"I'd like to talk to the detective who's in charge of

"the tarwacki homicide, because I think

I have information as to who killed them."

This officer obviously calls me right away home.

I believe it was three in the morning or something

like that, so I obviously come to work right away.

I start interviewing Patricia wilds, and she

brings up the name of Keith lintz...

Keith lintz, who we had talked to initially

but was not on the radar.

26-year-old Keith lintz with someone

they interviewed on the very first day of the investigation.

His mother, Sherry, told them

Keith was at home with her at the time of the murder,

and back then, they had no reason to doubt her.

Patricia tells US that she was living with Keith lintz's

brother or half-brother, and on the night

of the homicides, he came to the trailer,

and she said Keith was...

Just bouncing all over the place.

He kept looking out the window, and she... she asked him,

"what are you doing?" She said.

"The cops are after."

"Why are the cops after you?"

And he said, "because I left my effin'

footprints in the yard, and they're gonna find me."

Patricia tells them that Keith was heavily

into crystal meth,

and that night, she was afraid of him.

One of Patricia wilds' big, alarming concerns

was just the way Keith was acting, you know,

it was... he was acting berserk, and she said he had a gun

in one hand, was waving it around,

but she also observed him with a couple

other weapons in his belt line.

That started the ball rolling with Keith lintz,

and we really started to dig in on him as our main suspect.

To confirm Patricia's story,

detective Suarez tracks down the mother of Keith's child.

She's in bad shape.

It turns out that within a month or so,

I believe, of the homicides,

Keith had choked her, beat her, choked her,

and we were able to confirm this through south bend police

department records that he...

We obviously now know, he's got the propensity for violence.

Now that we really got our teeth sunk in to Keith lintz,

we start looking for his inner circle.

We start getting more calls.

The next big break really comes from another

ex-girlfriend.

She had a birthday party for one of her sons,

and the mother told her,

why do you have Keith lintz here?

He killed the tarwackis. Get him out of my home.

I don't want him in my house, so that started a fight,

she said she asked him,

"why do people think you killed the tarwackis?"

And he told her,

"well, because they found my footprints there,

"but I was just taking a shortcut

to my grandparents' house."

It seemed to believable.

If you're gonna make a story up,

why do you make the footprints in the snow up?

Because we never had released that,

and people didn't know we had that as evidence.

Detectives now strongly believe Keith murdered

Carolyn and John tarwacki, but they need proof.

They go back to Sherry lintz, hoping to break his alibi.

She reiterates the Keith was sleeping on the couch at 8 A.M.

And that she drove him to work at nine.

So now we're... We're working on it.

We have to confirm his timeline,

and at that time, he was working at Walmart

in mishawaka, Indiana.

We were able to determine through work records

that was not true.

He never did show up for work.

He didn't call in sick.

He didn't call in at all, so we know that he's not there.

We believe mom's lying.

If only detectives had checked Keith's alibi

back on day one of the investigation,

they would have realized that he had both the means

and the opportunity to kill the tarwackis.

It's not uncommon to see in a lot

of cases go cold... In this case, three years,

it doesn't matter if it's three months, three years,

30 years...

I'll often tell investigators, the name of

the offender is probably already in the file.

He's probably already even been interviewed

and falsely or wrongly screened out or excluded.

And I say always go back to what you did first

and re-examine it with fresh eyes,

and we see in this case, sure enough,

he's spoken to in the canvass and not asked

the right questions and ruled out.

Obviously, Keith is on the radar now.

We tried looking for his whereabouts.

We find out that Keith has fled to Nashville, Tennessee.

The next day, I had to go to the doctor.

My blood pressure was 200 over 195.

We have to track him down.

If Keith did this, he needs to pay for it.

Investigators believe Keith lintz

killed Carolyn and John tarwacki.

After an exhaustive search, they finally track him down

in a Nashville jail,

imprisoned on some minor traffic charges.

So Keith and I have history.

He doesn't like me. I don't like him.

There comes a point in time where you really

have to suck up your ego as an investigator.

As much as I want to go interview Keith,

I know that if I go, he's not gonna say a thing.

So I sent a couple other detectives to talk to him.

They do lengthy interviews with him.

He denies, denies, denies being involved,

but he also thinks that he can beat a polygraph,

and he... he volunteers to take polygraphs.

He failed both tests miserably.

So we know that Keith is our main suspect,

but we don't have that final nail in the coffin.

But then they get a phone call from

a man by the name of Shane Zimmerman.

He says he's got information about the homicide.

Shane Zimmerman is hitting the lotto,

hitting all seven numbers in the powerball.

It's just something that you don't expect

out of the blue to come,

even though we are on the right trail.

Shane Zimmerman describes himself

as a childhood friend

of the prime suspect, Keith lintz,

who just happens to be sharing a cell with him

at this very moment.

Shane says, "Keith told me he did it.

"He can't take it back, but he says he did it.

He was crying... one night, he was in his bunk, crying."

And Shane says, "what's wrong?"

He says, "I killed them. I killed those people."

He goes, "they didn't deserve to die,

but I can't take it back."

In order to secure a conviction,

investigators need Keith's confession on tape.

Shane Zimmerman didn't want anything.

He said, "I've screwed up my entire life."

He goes, "for once in my life, I'm going to do

something right."

Shane agrees to wear a wire

and heads back into the cell.

But we tell them, "don't ask questions.

"You don't interrogate. You don't interview.

"You just act as a listening post.

"If he wants to talk about it, you talk,

you listen."

On their end,

police push Keith in a series of interviews,

keeping the murders at the top of his mind.

They said, "hey, Keith, we know sometimes you can go into

"drug-induced hysteria, and this is what happened

in this case, isn't it?"

And, you know, obviously, he denied it there,

but when he went back into the cell and was talking

to... to Shane, Shane...

He told Shane, he goes, "man, they had it...

They had it right on. That's what happened."

Finally, Keith breaks down and spills

the whole story of the murders to Shane.

Zimmerman was a hammer that we hammered that nail home,

so it was an incredible stroke of luck.

With their informant's help,

investigators are able to piece together

John and Carolyn's final 24 hours.

We find out that Keith and his brother, Brian,

are drinking all night long.

They're doing drugs the entire night.

That morning of the murders,

Keith gets in a fight with the mother,

because he wants more money to go buy drugs.

This is very early in the morning

prior to the homicides.

We believe that after the mother would not give Keith money,

he probably planned on doing a home invasion.

John is finishing getting ready for work.

He is shaving.

Carolyn's on her computer at 7:03.

And sometime between there and 7:45, Keith lintz is

walking down the road and walks down that back alley.

He may have seen this house that looked like

an easy target,

and knowing the area, he walks around to the back.

He then goes in the house.

Keith used to have pit bulls,

so this guy was not scared of dogs.

He lets wrigley the dog into

the back room and closes the door behind him.

I don't think he was expecting

for John and Carolyn to be home.

Especially if the dog was, like, in the back,

maybe he thought, "these people are gone.

Maybe there's nobody home."

I believe that she saw Keith

coming in through the back door.

Keith already had his gun out.

He may have been doing, obviously,

meth and maybe some coke or crack.

I believe that she screams.

John comes out of the bathroom, encounters Keith.

He was just out of his mind.

I don't... I don't think that he went

in there with the intent to murder anyone.

I think he went in there with the intent to Rob,

and all of sudden he'd just been confronted by two people.

It's a fight or flight, and he decided to kill them both.

I think my biggest takeaway from this case

was not to prejudge what you may see at a scene.

This case would suggest that maybe there was emotion here

that had evolved to

a certain level where people got angry

and perpetrated violence,

and really, what it says to me, is... is sometimes, you know,

by sheer happenstance or... or drug use,

it can culminate in explosive violence in a way that seems

personal when really, it's just

disorganized, frantic, unexplainable behavior.

Keith lintz is charged with

two counts of first degree murder.

He's convicted and sentenced to life

without the possibility of parole.

The timeline was incredibly important, because you had

this 35-, 40-minute window

where this crime occurred, and putting together

this timeline

made it absolutely clear, when we caught the guy, who it was.

As the father, John tarwacki, said, there is no closure,

and I also believe there is no closure.

You may get a conviction,

but it's not gonna bring your kid back,

not gonna... It's not gonna change anything.

Every time Christmas comes around, every time a birthday

comes around, they're not gonna be there.

But what sticks with me most about

this case is just how senseless it was.

These were two normal people getting ready for work,

and somebody made up their mind that they wanted something

and was gonna do whatever they could to get it.

It just... it's senseless. It made no sense.

And it still doesn't, even after all this time.

I don't know how you recover from that.