[ominous music playing]
This was an unplanned attack.
She had suffered severe trauma.
[Det. Everett] This complete innocent person
is now taken from her family
[Jennifer] She was an amazin mom to her kids.
Her family was her world.
The killer would be someone familiar with this facility.
And the odds of them being there are still high.
[Linda] He was a dark personality.
He's someone who might commit or thrill kill
for the pure excitement.
[Det. Everett] Life insurance is a motive.
Is this something that he concocted
to get this massive payout?
He had an issue with not liking women.
He was prepared to take this rage out on her
and make sure she didn't liv
to tell whatever she saw them doing.
[narrator] Every day in North America,
dozens of people are murdere
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.
Florence, a thriving industrial center
in the heart of Kentucky.
[Det. Brian] Florence is a suburban community.
It is very close to Cincinnati.
We are just south.
We have a lot of industry
that chooses to be headquartered
and distribute in our region.
[Linda] Florence, Kentucky is considered one
of the safest places in the entire state.
We have a very large law enforcement presence
and so the crime rate is extremely low.
[narrator] But, the morning after Memorial Day,
global pharmaceutical conglomerate,
Thermo Fisher Scientific becomes the site
of a real-life murder myster
At 7:18,
Boone County dispatch receives a 911 call from Ed Yuska.
[man speaking]
[Ed speaking]
[Det. Everett] They had foun the body of a woman
and they felt like she was dead.
[Ed speaking]
[wailing]
I arrived there at 7:26 AM.
When you walk into the front door
of Thermo Fisher Scientific
you can either look out over at the warehouse
or go to the office area
where the supervisors had their offices.
The victim was laying around the corner
by the door that goes into the office area.
[Linda] A plastic trash bag had been tied over her head
It was a very bloody scene.
Her hands were bound behind her back
with tape around her wrists.
That would definitely lead us to the initial conclusion
that this is a homicide.
[narrator] The victim is 42-year-old Michelle Mockbee
a loyal and trusted employe of Thermo Fisher.
Michelle worked at Thermo Fisher Scientific
for 16 years.
She loved her job. It was like a big family
and she fit right in.
Everybody loved her there.
[screaming]
[Jennifer] Michelle was an amazing mom to her kids.
They were her world and her family was her world
And she also just loved baseball
and loved the Cincinnati Red
I miss her laugh, her smile
I just miss her being there
being there for all of us.
[narrator] Heading up the investigation
into the murder of Michelle Mockbee
is Detective Everett Stahl
of the Boone County Sheriff's Office.
Assisting him is Detective Brian Cochran.
I think the thing that made it infinitely differen
was the potential scope for evidence
and the size of the warehous
The building where this event took place
is actually about the size of four football fields.
With the security in the building,
they had a key pass system,
so they did have monitoring of who came
and went from that facility
We suspect the killer would be someone
that would be familiar with this facility.
And the odds of them being there
are still relatively high.
And so everyone that was there was containe
and not allowed to leave at that time.
[narrator] To find Michelle Mockbee's killer,
detectives will need to unravel the final 24 hours
of her life.
[Linda] Michelle's body had not been there that long
Rigor mortis had not set in.
She was still warm,
and the blood itself looked fresh.
Michelle had wounds all over her body.
It was obvious that she had suffered
severe, severe trauma.
Michelle had a gash in her throat
and some odd-looking cuts on her fingers,
maybe defensive wounds
from trying to defend her head.
Her eyes were beginning to turn black and blue
which a lot of times is associated with a wound
where a person is struck in the nose.
[Det. Everett] This appeare to be an unplanned attack
and typically the weapon in this kind of case
is a weapon of opportunity.
What could cause this?
It was pretty evident that the gash in her neck
and the gash in her wrist were one sharp item.
And we were looking for something heavy
that could've caused the serrated cuts
on her fingers.
[Michael] The use of a makeshift weapon
can complicate an investigation.
Number one, police don't know who they're dealing with
in terms of motive.
When you have an offender for instance
who brings a firearm to a scene,
that lays out a certain set of circumstances
that can lead you one way or another.
The second challenge is,
experts can match bullets removed from bodies
to specific firearms
or wounds on a body to specific blades.
But when you're dealing with something
really idiosyncratic,
there's no way to necessarily quantify
how those injuries were caused by that weapon.
[narrator] Having examined the body,
investigators turn their attention
to the rest of the crime scene,
discovering Michelle's purs and other personal items.
The fact that Michelle was still carrying
all of her personal items,
told officers that she had not actually made I
into her office yet.
So it seemed as though
Michelle was attacked closely in time to arriving
Michelle's shoes were in her pursue, which was odd.
So when we went back and we looked
at the bottoms of her feet,
they were clean.
That would lead us to believe that the killer dragged her
out on to that mezzanine are
and that she did not walk out there
under her own power.
[narrator] Investigators now believe
that Michelle was killed in another area
of the second floor.
And then her body was dumpe in the mezzanine.
The body was moved approximately 75 to 100 ft.
The path where we believe Michelle was dragged
leads us from the storage area of the mezzanine
into the office areas.
In front of Michelle's offic
there was a larger pool of blood.
When that blood pool was treated with luminol,
the trace pattern of someon wiping back and forth
through that pool was revealed.
It appeared that the killer was trying
to manipulate the crime scen
and clean it up.
The detectives discovered
that there were fresh pry marks
on the door of Michelle's office
and it appeared as though something sharp
and blunt had been used on the door.
Our theory is that,
as she reached the top of the steps,
Michelle has a confrontation
She's punched,
knocked to the ground, semi-unconscious,
she's beaten in the head,
her arms are taped behind her back,
and then she is dragged out into the mezzanine.
The severity of the violenc suggests that
this was very much an impulsive impromptu crime.
As though the victim had interrupted the offende
or caught him doing something red-handed
and that they were prepared
to take this rage out on Michelle
and make sure she didn't liv
to tell whatever she saw them doing.
[narrator] In the brutal murder of 42-year-old
long-time Thermo Fisher employee, Michelle Mockbee,
detectives have locked down
the distribution center in Florence, Kentucky.
Believing someone at the facility is her killer.
[Linda] When Ed Yuska who ma the 911 call was interviewed
he described, having a basically two decad
or more long relationship with Michelle.
They both worked in the second floor office spac
in the building.
And so the ones who worked up there
were very close to each other.
While Ed Yuska reported that Michelle normally arriv
for work at 8:00,
one day a month, she would be there at 7:00 A
to collect time cards and do payroll.
On the day of this offense,
Michelle was coming in at about 7:00.
Ed tells police, when he arrives
at Thermo Fisher Scientific
right around 7:00 AM
and swipes his employee car which creates a record,
when he arrived on the second level though,
the lights are all out
and so he has to walk down the hallway
and around the corner to actually flip
the lights on for that level
So he flips on one of the lights
and he sees the red stain on the carpet
and he thought, "Well, that's kind of weird,
it kind of looks like blood.
I wonder if somebody got hurt."
And they find Michelle's bod in the mezzanine area.
Ed then calls 911 at 7:18.
[narrator] Looking to confir Ed's story,
police turned to the distribution center
security footage.
When officers review the surveillance video,
they were able to confirm Ed Yuska's story
that he had arrived right around 7:00 AM.
However, Michelle had arrived in the parking lot
at 5:53 AM.
Backing off from the time
that the 911 call came in at 7:18,
we're looking at a window of time
of basically about an hour and a half
for this to have occurred.
However, because she was still carrying all
of her personal affects and it didn't appear as though
she'd actually even made it to her office,
officers believe that she was attacked
literally within minutes of entering the building,
probably in the neighborhoo of 6:00 AM.
[narrator] Having narrowed down
Michelle's time of death,
detectives continue with their investigation.
And then a man arrives at Thermo Fisher,
begging to speak to Michelle
Dan Mockbee who was Michelle's husband
arrived at Thermo Fisher at about 9:30 that morning.
We made notification that Michelle was deceased.
He had almost no control over himself
when I gave him the news.
He just seemed destroyed.
I gave him a minute to kind of absorb the information.
But obviously we were lookin at him as a suspect
because you always look at the husband as a suspect
in something like this.
And I hate to say it,
but sometimes people are really good at acting,
like they're upset.
Besides the fact that he was Michelle's husband
because he was a supervisor,
Dan had all of the keys and codes necessary
to be able to enter the building
and bypass the security system.
[narrator] Police escort Dan Mockbee
into Thermo Fisher to be interviewed.
I'd ask Dan, you know, "What was Michelle doing?
Why was she coming in so early?"
And he said that it was the start
of summer break for their ki
and so she wanted to come in early,
she wanted to get her paperwork done,
and send off
so she could come home
and take the girls to the po
and start enjoying this first day of summer
with the kids.
Dan said that Michelle had taken the kids
to her mom's house to spend the night,
and then it was date night for him and Michelle.
They went to Applebee's for dinner.
When they got home, it was around 11:00 PM
and they went to bed.
Michelle slept upstairs and Dan slept on the couch.
Michelle got up and she got ready
and she left at 5:30
and Dan knows it was 5:30 because when she was leaving
she stopped by, gave him a kiss on the cheek
and headed out and that woke him up.
Because Dan Mockbee reports being home alone
between the time Michelle left at 5:30 AM
and the time he shows up at Thermo Fisher Scientific
at 9:30,
there's no one that can vouc
for the fact that Dan was home alone
or the alibi that he was providing the detectives.
And then also it really bothered me a little bit
that Dan and Michelle would not sleep together.
In my role as a detective,
I've seen people who are on their way
to either divorce
or some kind of domestic dispute
typically sleeping separate
And that means there's trouble in the relationship
there's something going on inside their marriage
that is causing them to want to sleep separate.
We needed to work real hard on figuring out,
was Dan telling us the truth
We did also discover
that Dan and Michelle were in some debt.
So that was something that was very important to look at.
Michelle also had life insurance.
I see life insurance as a potential motive.
It's a lot of money.
And the beneficiary is Dan.
And so, is this something
that he would've potentially concocted
to try get this massive payout?
[narrator] Having establishe a motive,
investigators need to determine
whether Dan had the opportunity
to commit the crime.
[Linda] There is no evidenc that Dan had been on
the premises of Thermo Fisher Scientific
or entered the building in any way on that morning.
Prior to 9:30,
he was not on surveillance video
and his swipe card was not used
on any of the doors in the building that morning
So he was eliminated as a person of interest.
Not for one minute did I ever think
that Dan had anything to do with Michelle's murder.
He just lost the love of his life.
[narrator] Investigators asked Dan
if he knows of anyone at Thermo Fisher
with a grudge against Michelle.
Dan says that someone had tried to break
into Michelle's office months prior.
After that happened,
Thermo Fisher secured the door to her office.
She had kept like petty cash and maybe some valuables.
But after the break in,
Thermo Fisher removed all of that from her office
Dan was not able to provide
any more information about who it was
that would've broken into the office
because they weren't able to determine who it was.
[narrator] Investigators now wonder,
could Michelle have been killed
in a robbery gone wrong?
If Michelle was to exit that stairwell
and someone was attempting to break into that office,
Michelle would have been nearly face to face with the
and there's a strong likelihood
that the person would've been surprised by Michelle.
[Linda] The question in min would be,
what in the world could be located in Michelle's offic
that was important enough
that somebody would be willing to break in
to get to it.
[narrator] Working the theor that dedicated
Thermo Fisher employee Michelle Mockbee
was the victim of a robbery gone wrong.
Investigators shift their focus
to the employees working at the distribution center
the morning of her murder.
I mean, this conjures images of the board game clue
or Murder on the Orient Express
where you have a handful of people
in an enclosed space
and you have to figure out
which one of them did it and why.
Detectives were able to eliminate eight employee
who were on scene
before the 911 call was made
simply because of productivity reports
that identified everything they were doing
in the building
as well as their indication
that they saw each other in the warehouse.
We did a criminal history check
with the other employees.
This guy, Doug Tungate had some issues with alcohol
he was on probation from an alcohol arrest.
And so certainly that starts piquing interes
in Doug Tungate.
Doug is a temporary employee
assigned to this morning cre
as someone who would put product away.
He had been convicted several years earlier
of receiving stolen property.
There were indications that someone attempted
to break into Michelle's office
and so someone who had a criminal history
for theft-related defenses
would be someone investigato
look at more closely.
The fact that Michelle had petty cash accessible,
could Doug have been desperate enough
to go in with the intent of stealing
and been interrupted
and reacted the way he did?
[thuds]
We learned that Doug Tungate arrived
at Thermo Fisher Scientific at 5:40 in the morning.
Sat in his car for a few minutes
and then went in and clocked in at 5:45.
And so he arrived just minut
before Michelle was murdered.
[narrator] With Doug in their crosshairs,
investigators interview him on the premises.
[Det. Everett] Doug seemed very nervous
but he was very upset by the whole thing
at the same time.
When he arrived, he entered the building
but he wasn't permitted to clock in until 5:45.
And so he just hung out for a couple of minutes
by the timecard machine.
Warehouse supervisor, Joe Siegert,
pulls up on his forklift
and they start having a chat.
And Doug has his coffee sitting on the time clock.
He said he looked up and he saw Michelle
walking in towards the time clock
and he just said, "Oh, I apologize."
She said, "No, that's fine. Good morning."
And she grabbed the time cards
and then went through the door right next to the time clock.
So after he saw Michelle, he went into the break room
he sat down for a minute.
And then once it was 6:00, he went out
and he started doing his jo for the day.
[narrator] While there are no witnesses to Doug's work
investigators find another w
to confirm his alibi.
Thermo Fisher Scientific employed
a computer-generated system
to scan in items
as they are being removed from trucks
and then scanned again
once they're placed where they ultimately will be.
The program itself is done
to basically keep track of inventory
and ensure productivity
as far as the employees are concerned.
But upon examining Doug Tungate's record,
there is a gap of about 20 minutes
right when he began his shif
which was in the 6:00 hour.
[Det. Everett] That was concerning to us
that there were zero scans in that time frame
that Michelle was killed.
So Doug Tungate did have that opportunity
to commit the murder.
Doug explains to us that,
"Yes, I clocked in at 6:00
but I have this paperwork I have to fill out
with the equipment that I'm gonna use"
and that's the reason behind that gap
in his activity.
Other employees, they rememb
seeing Doug out on the floor
And so we have corroboration.
[narrator] Based on the workers' statements,
investigators conclude
that Doug likely didn't have the opportunity
to kill Michelle.
They move on to the other worker
who saw her arrived at Thermo Fisher,
Joe Siegert.
[Linda] Joe Siegert was one of the last people
to see Michelle alive.
So he was a person
that detectives definitely wanted
to take a closer look at.
[Det. Everett] So, when we are conducting interviews
Joe speaks to the location manager.
And Joe's only question was
"Am I getting paid for the rest of the day?"
I kind of stopped in my tracks.
And I thought,
"This is the question you're asking
when your co-worker's been murdered upstairs?"
Joe's known Michelle since she started.
And so, we start questionin
whether or not there is something
between and he and Michelle that caused him
to have an issue with her.
[narrator] Detectives question Joe,
digging into his lack of emotion
around Michelle's death.
[Linda] Joe is just sort of an odd person.
He didn't congregate
with the other employees in the break room.
He would always go out to the parking lot by himself.
He was just kind of a loner
And then Joe told us that he had gone upstairs
to the area of the crime sce
and he had gotten bags of rubber bands.
Joe was in the area of the crime scene
at the time of the murder,
so we looked at Joe as one of the people
that we really needed to sink our teeth into.
[narrator] Investigators ask Joe about his whereabouts
during the window of time that Michelle was murdered.
Joe Siegert arrived on
Thermo Fisher Scientific property about 4:50 AM.
[Det. Everett] Joe was one of the four supervisors.
So he was one of the folks
that actually had a key to the door
and he had the alarm code.
Then Joe had scanned his car got clocked in at 5:00 AM.
And then he started unloading a truck at 5:30.
He says that he went upstair at some point,
he got these rubber bands.
And then he unloaded the trucks straight up until 7:0
which was the time that all of the employees went on break.
Upon reviewing the employee productivity records,
it did appear that there was a large gap
in Joe Siegert's timeline
right around the time that Michelle would have arrived
So we collected DNA,
fingerprints, shoe impressions,
and Joe Siegert's cell phone
[narrator] When investigator examined Joe's phone,
they make a surprising discovery.
Detectives did take a close look
at Joe Siegert's social media related activity
and Joe was sort of a dark personality.
He liked horror movies
and often posted things about different horror films
And so detectives obviously were a little concerned.
When investigators see
that Joseph's reaction is very flat,
he has a blunted affect when talking
about Michelle and the homicide, that's a red flag.
And then when they find that he has this penchant
for watching gore or horror movies,
that could also be another indicator that perhaps...
he's someone who might commit a thrill kill
for the pure excitement of that act
and what that would feel lik to have that kind of power
over another human being.
[narrator] With suspicion swirling around Joe,
police have him take a polygraph.
Joe passed the polygraph.
He was also witnessed by employees doing his work
And so, we were able to eliminate Joe Siegert.
[narrator] Having eliminate Joe Siegert as a suspect,
detectives find themselves at a crossroads.
But then, Ed Yuska comes forward
with new information
that shifts the direction of the investigation.
Ed immediately told them that he was missing
an industrial tape gun
that he kept on his shelf in his office.
These tape guns are unique,
and that they have a serrated edge,
sharp metal edges,
as well as a big blunt force trauma
of the tape roll.
We brought the tape gun to the medical examiner.
He was able to match the angles of the tape gun
up to the injuries on her head.
That was a light bulb moment
This was our murder weapon.
[narrator] In the vicious homicide of Michelle Mockbee
detectives have identified the murder weapon,
an industrial tape gun.
Finding it could put them one step closer
to catching the killer.
Every available unit
was involved in searching the entire facility
for the missing tape gun.
[Det. Brian] We did not fin the tape gun.
It has somehow gotten out of the building.
We have to come to the conclusion
that someone took the evidence away
from the scene intentionally.
[Linda] There were two outside security cameras.
Upon reviewing the surveillance videos,
officers were able to determine
that there was a red pickup truck
that actually left
the Thermo Fisher Scientific property
right at 6:30 AM.
That same pickup truck is seen returning
to the Thermo Fisher Scientific parking lot
at 7:05 AM.
My partner on the case says that's the janitor,
David Dooley, that's his truck.
David actually left on the backside of the building
which is a route not many people take.
The fact that he took that other route out
was something that really caused us
a lot of suspicion.
David Dooley served as the janitor
for the entire facility.
He had within his cleaning closet
literally all of the materia
that you would need to try to clean up
your crime scene.
[narrator] Looking for more informatio
about their latest suspect,
detectives run David Dooley's name
through the police database
David Dooley had a criminal history
that included multiple convictions
for burglary and theft,
and he had spent considerable amount of time
in the penitentiary.
David has been in and out of jail a lot.
That tells me he's got major issues with authority.
Combine that with the fact
that David has the criminal attitude
of wanting to get ahead
without doing the work.
You have a recipe for disaster.
[narrator] Armed with this new information
about David's criminal recor
investigators sit him down for questioning.
When David Dooley was interviewed,
he indicated that he had been working
as a contract employee
at Thermo Fisher Scientific
for a period of about six years.
His duties involved cleaning the office area
and the warehouse.
Dave and Michelle would communicate
from time to time via email,
talking about the need for certain supplies
to complete his job.
[narrator] Detectives take a closer look
at David's timeline,
to see if he had the opportunity
to commit the murder.
David arrived at the building about 20 minutes
before his shift would've started at 5:00 AM
He started his work in the break room
and went up to the second level
using the elevator.
At about 5:30, emptied the trash,
and indicated that he was back down
on the first level cleaning by 5:35.
[Linda] He then laid out a timeline
of working his way through the building,
right up until the time
that the 911 call came in at 7:18 AM.
David said that he is typically not seen
in the office area
because no one is there at that point.
And it's hard for anybody to corroborate the fact
that he was in there cleanin
because everybody else is out in the warehouse working.
[narrator] When detectives confront David with the fac
that he left the facility following Michelle's murder
he claims there's an easy explanation for that.
He brushed it off as, "Oh, I forgot to tell you."
He said he'd left that morning
because his wife had taken an Ambien the night prior
and he was concerned that she was not feeling wel
"So, I needed to go home and check on her."
[David speaking]
- [man speaking] - [David speaking]
[man speaking]
[David speaking]
With the nature of Michelle's injuries
and the biological evidence that we had upstairs,
we made a point to look at everybody's shoes
We did a visual inspection of their clothes.
The one thing that was noticed about Davi
was how clean he was.
Detectives also were aware
from walking around the building themself,
that the building itself was filthy.
And so, it was unusual that David did not appear
to have any dirt on him anywhere.
[narrator] Now, believing th David may have gone home
when he left Thermo Fisher from 6:30 to 7:05 AM,
detectives turned to David's wife Janet,
who also works at the compan to check his alibi.
When asked if she had seen David that morning,
she indicated that she knew
that he had left around 5:1 or before then,
and that she did not see him again after that.
He hadn't returned home, which contradicted his story
So, obviously, there are huge problems.
[narrator] Unable to corroborate
David's version of events,
investigators returned
to the company surveillance video
looking for evidence that could link him
to Michelle's murder.
One of my responsibilities in this investigation
was to review 30 days' wort
of Thermo Fisher surveillance footage.
And what we found was that every other day,
David Dooley comes in one way and goes out the same way.
Except this one day, where he left
around the back side of the building.
It was completely out of routine for him.
The question is why would David go out
and then, back in at an entrance
that he's never used before?
The most plausible explanati
is that he wanted to skulk around unnoticed
as he disposed of the weapo he used to murder Michelle.
[narrator] In the murder of beloved 42-year-old,
HR professional and mom of two, Michelle Mockbee,
detectives have zeroed in on a prime suspect,
the only person to leave Thermo Fisher
after the murder,
janitor David Dooley.
The employees reported walking
into the building with David Dooley,
and then nobody reports seeing him again
until he returns on the property at 7:05 AM,
after Michelle had been brutally murdered.
At 7:05, Joe Siegert is sitting in his car
taking a break
and he said that he saw David pull in.
David actually walked over to him, to his car
and pointed out that,
"Oh, I had to run home and change my pants
because I ripped my pants."
Joe thought that it was very odd
that he would come over to make a point to tell him
about why it was that he lef the property.
But another reason why it was odd to Joe Siegert
is because all persons who work
at Thermo Fisher Scientific
are required to be wearing steel toe boots
while they're on the propert
And at that point, David Dooley
was wearing white tennis shoes.
The other employees saw him come in earlier in the day
and he was wearing boots at that time.
Detectives believed that he had
taken the boots with him and disposed of them
after he left Thermo Fisher Scientific.
Following up on the work
David had been assigned that morning,
it turns out that a number of these tasks
had been shirked and never completed.
Specifically, he had failed to clean out
a number of garbage cans,
which suggested that he was doing something else
between 6:00 and 7:00 AM.
More than enough time to commit Michelle's murder
and try to cover his tracks
We never found the actual weapon.
Nor did we find the clothes that Mr. Dooley was wearing
But what we did find was screwdrivers.
This one specific screwdrive
kind of matched the marks on Michelle's door.
That screwdriver was sent
to the Kentucky State Polic crime lab
and they find that it was a match.
[narrator] The evidence against David is mounting.
But there's still the question of motive.
The question still remained,
why would David feel the need
to break into Michelle's office to begin with?
[Det. Everett] Part of the struggle with figuring out
what the motive might be is what was in it for David
Was he looking for something
specific inside Michelle's office?
Joe Siegert tells investigators months before,
suspicions had arose about the hours
that were being put in
by Janet and David at the facility.
And David and Janet were recently admonished
that they needed to be a lot more careful
with their use of the time clock.
[narrator] Investigators question
if there was more to the matter,
than just David and Janet not being careful
about when they punched in and out.
When detectives searched Michelle Mockbee's office,
they'd found all of the timecards
that David and Janet Dooley had turned in
over a period of months, if not years.
It was clear from those timecards
that Janet was clocked in every day
over and above what her contract called for
That was something pretty interesting
because through the surveillance video,
on multiple days,
I just see David's truck entering
and I don't see Janet's car entering.
I thought, "Well, let me start looking
at Janet's text messages."
She is actually talking about being at home
while she's clocked in at Thermo Fisher.
They were bilking the compan getting double, triple paid
Light bulb that goes off is
David was going into Michelle's office
to collect his and Janet's timecards to remove those,
and to prevent them
from getting caught by the company.
Michelle had discovered that Janet and David
were stealing from the company.
[narrator] Continuing to build their case,
detectives questioned David again
about the inconsistencies in his timeline.
[Det. Everett] Initially, he said that he was
in a back hallway cleaning.
Well, then, he said he was never
in the back hallway cleaning.
[Everett] When we continued to confront him,
he got very defensive.
[Linda] One of the detectives came I
with another industrial tape gun...
that was similar to the one that would've been used
as the murder weapon in this case.
And you could see David's demeanor visibly changed
and immediately, he terminated the interview
and said that he wanted an attorney.
[Det. Brian] It was kind of his "Oh, no" moment.
That told me that he knows that a tape gun
was used to kill Michelle.
[narrator] With this final piece of the puzzle,
detectives are now able to reconstruct
Michelle Mockbee's final 24-hours.
Michelle Mockbee leaves the house
at 5:30 on May 29th, 2012.
Michelle arrives at Thermo Fisher Scientific
at 5:53 AM.
She had a brief interaction with some employees
and proceeds up the back stairwell to her office.
So, Michelle enters the office area at 6:00 AM.
She catches David Dooley
trying to break in to her office
to get the timecards from the past
that proved the theft from the company.
David Dooley was surprised
by Michelle arriving much earlier
than she was expected.
Michelle said something to h
about why are you breaking into my office.
And David had an issue
with not liking women, basically.
And so, for a woman to talk to him like that,
that wouldn't sit well with him.
[Linda] He coldcocked her and she was knocked out.
David Dooley decided that Michelle Mockbee
could not be alive to tell the tale
of what happened to her that day.
And so, he took the industrial tape gun,
proceeded to bludgeon Michelle in the head,
he restrains her with tape from the industrial tape gun
[Everett] David drags Michelle to the mezzanine,
collects her belongings,
and places them out by the body.
And then, David leaves Thermo Fisher
in his red truck at 6:30 that morning.
[Keira] It may seem that this is a black swan event.
It's completely rare and random.
But actually, he's driven himself to this behavior.
Each of the decisions he makes to commit fraud
and try to cover his tracks
is an essence a psychopathic snowball
that continues to build until he's forced
to kill Michelle to save himself,
and so this is a fraud detection homicide.
[Linda] In many ways, this investigation
was like the game Clue.
Because you knew the where and you knew the when,
but the who and the what were the main things
that detectives needed to focused on.
And so, you know, peeling away the layers
of this investigation
was much like playing one of those games
where it's a process of elimination
until it left us with only one man standing.
[narrator] David Dooley is convicted of murder
and tampering with evidence
He is sentenced to life in prison.
The hard part is you look at this mother
who just was wanting to get her job done early
so she could spend the day with the kids,
and that's the shame of it,
was that Michelle was so devoted
to her husband and her kids
And this completely innocent person
who's done nothing wrong to anybody
is now taken from her family.
[Jennifer] I want people to remember
how kind Michelle was
and just how loving she was
We think about her a lot.
She'll always be in our hear
and she'll just always be remembered.
On the year anniversary of her murder,
we all went to the Reds game,
and we all wore these red wristbands in her memory
So, we know she'll be smiling down at that.
We definitely still celebrate Michelle
as if she was still here.