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[music playing]
NARRATOR: To solve a ***, investigators
needed to find the fatal bullet.
But where was it?
Could the laws of physics solve the mystery?
If not, a killer would walk free.
[theme music]
World War II, in the skies over Europe American Airman
fought a deadly and dangerous war.
For every 100 airmen who flew missions over Europe,
70 never came back.
One of the highest casualty rates in the history
of warfare.
Walter Yokum was one of the fortunate ones.
TONY MATTHEWS: He was in the Air Force in World War II.
He was a waist gunner in a B-17 And survived
34 missions over Nazi held territory.
NARRATOR: Yokum risked his life, and almost
lost it countless times.
But only his family and fellow veterans knew it.
DAVID BROBERG: He never talked about it,
so I didn't know what he did in the military.
It kind of surprised me because he's
such a conservative fellow, you just
can't imagine him being behind a machine gun in an airplane.
NARRATOR: 76-year-old Yokum, a widower and retired accountant,
lived by himself on the outskirts
of Boulder County, Colorado.
On a fall day in 1993, his housekeeper
noticed something was wrong.
TONY MATTHEWS: She went and knocked on the door,
got no answer, she said it's very unusual for him
because he's a pretty punctual guy.
Was never late, was always there when
she was supposed to show up.
DAVID BROBERG: She went around the back of the house,
and decided to knock on the back door.
And noticed that there was a broken window.
And she got concerned at that point
and decided to notify the police.
NARRATOR: Investigators from the Boulder Sheriff's Office
discovered Walter Yokum dead at the bottom of the stairs.
He had been fatally shot through the neck.
DAVID BROBERG: I don't think I slept for a couple of days.
It's hard to imagine somebody that you know
has just been violently murdered.
NARRATOR: Outside, detectives noticed
several clear foot impressions in the mud.
Crime scene technicians took plaster
casts for future comparison.
STEVEN AINSWORTH: There was a particularly good set
of footprints that cast from that.
And they were a lug sole type of a boot.
Kind of work boot kind of a sole.
NARRATOR: The point of entry was through a broken bedroom
window on the ground floor.
There were muddy footprints leading to the foyer.
At the stairwell, detectives found gunshot residue.
TRIP DEMUTH: You could see the pattern of the gun powder
on the wall left an outline where the barrel--
the end of the barrel was.
It demonstrated, exactly, where the shooter was standing
at the time that he killed Mr. Yokum.
NARRATOR: There was an empty gun holster
upstairs, on the dining room floor.
TONY MATTHEWS: We called the son who--
and said, did he have again guns?
And what were they?
And he says, oh yeah, my dad had his .45
which he'd kept from World War II.
He says everybody kept their guns when they left the army.
NARRATOR: This was a distinctive gun.
It was a Colt semi-automatic used
by many World War II service men.
Soldiers routinely scraped off the gun's serial numbers
after the war.
But Yokum's gun was missing.
So to was his credit card and some cash.
Adding to the mystery, was the awkward position
of Walter Yokum's body.
He was lying on his back, with his arms
extended, and his knees in the air.
STEVEN AINSWORTH: Someone had come and moved him,
after rigor mortis had set in because he was nearly face up
with both arms somewhat in the air,
and gravity just doesn't allow you to do that.
NARRATOR: This meant the killer was
inside the house at least three hours.
Maybe longer.
TONY MATTHEWS: Our working theory, in the beginning,
was that this was a burglary, it was interrupted.
And what was really bad about that is that burglaries are
one of the hardest crimes to solve.
NARRATOR: The most bizarre clue was found near Yokum's foot.
It was the foil wrapper of a Reese's Peanut Butter Cup.
There was an empty bag of peanut butter
cups in the refrigerator.
TRIP DEMUTH: I would have to say that all we knew about killer
was that he wore boots, and he enjoyed
Reese's Peanut Butter Cup.
STEVEN AINSWORTH: That was a coldblooded killer,
someone that can do that.
Having just murdered somebody then
go through the refrigerator to see what there is to eat.
And then stand there and look at him
while you're eating some of his candy.
NARRATOR: Clues from the crime scene
indicated Walter Yokum most likely heard an intruder,
grabbed his gun, and was heading down
the steps when the intruder shot him.
TONY MATTHEWS: At the beginning of the investigation,
there was an autopsy.
And at that point, we discover that the bullet's
not in the victim's body.
So it's like, the next task for those of us going back out
to the scene is, we've got to find this bullet.
NARRATOR: This was a problem.
Without the bullet, investigators
would know nothing about the *** weapon.
And would have no ballistic evidence
once they identified a suspect.
TONY MATTHEWS: So everything suggested
there was one shot fired and it went
through the victim and out.
Somebody went on the roof, looked around,
couldn't find the bullet.
We looked in the gutter, couldn't find the bullet.
STEVEN AINSWORTH: How are we going to find this bullet?
Because if it exited the house, you got literally acres,
and acres, and acres, of places that bullet could be.
And it's a bullet that big.
NARRATOR: To find it, investigators
turned to the science department at the University of Colorado.
NEIL ASHBY: Once it enters the atmosphere,
then it's not likely to change its configuration,
although it might be tumbling.
So the three things you need to know
are, the initial velocity, the initial angle with respect
to the horizontal, and the amount of air resistance
that you could expect.
TONY MATTHEWS: We knew from the wound
it was probably a .38, .356, 9-millimeter.
That middle sized caliber.
We knew it wasn't the .22, it was too big for that.
And it was too small for a .45.
NARRATOR: A bullet from these caliber weapons
would be traveling at approximately
1,000 feet per second.
But the bullet passed through a human body,
went through the ceiling, and then the roof shingles.
NEIL ASHBY: It's very difficult to determine how much energy is
lost as the bullet passes through those three obstacles.
But in order to determine where the bullet falls,
you need to know the velocity just
after it passes through the roof.
NARRATOR: To study how much velocity was lost,
investigators reassembled everything
the bullet passed through.
A beef roast was used to simulate the victim's neck.
Behind it, was a piece of plaster ceiling
and, and behind that a section from the roof.
When the bullet was fired, its speed
was tracked with the chronometer, a device that
works very much like a radar gun.
NEIL ASHBY: There was a great deal more energy lost
by the bullet in passing through the victim and the ceiling
and the roof, than was originally thought.
NARRATOR: The next step was to determine the angle
at which the bullet left the house.
Gunshot residue told investigators approximately
where the killer was standing.
They knew where the victim was when he was struck.
And the hole in the roof told them where the bullet exited.
Investigators used a rod to approximate the trajectory,
which was 68 degrees.
NEIL ASHBY: If the ball is going almost straight up,
then the horizontal force due to air resistance is small.
And so you can solve the problem of a bullet going straight up
because it's a one-dimensional problem,
and get something that you can work with analytically.
NARRATOR: At a speed of approximately 850 feet
per second, the bullet exited the house at a 68 degree angle.
With gravity and wind resistance factored in,
scientists predicted the bullet would
be fairly close to the house.
TRIP DEMUTH: We asked a local treasure hunting
club to use their metal detectors.
And we marked off the entire yard and field beyond the house
with a grid.
And then we asked people to search
this grid for that bullet.
NARRATOR: And they found it.
Just 90 feet from the house.
It was a .38 caliber bullet.
TONY MATTHEWS: We were very excited.
We had our missing link. We had the bullet.
We really believe this was the bullet
that killed Walter Yokum.
NARRATOR: Unfortunately, it was of little value.
TRIP DEMUTH: Initially, I was pretty excited about it.
But then I was discouraged because the bullet was
so mangled that it wasn't going to give us any ballistics.
STEVEN AINSWORTH: The base was still relatively intact.
And about maybe a 1/4 of an inch up the base was intact.
But other than that, it was pretty mangled.
NARRATOR: Now investigators needed
to identify some suspects.
There probably was no prior relationship
between Walter Yokum and the killer.
So investigators checked police records
for anyone arrested for burglary around the time of the ***.
There was only one, James Dobson.
He'd been released from prison on a burglary conviction,
just a few days before Yokum's ***.
And he had a habit of eating at his crime scenes.
TRIP DEMUTH: He was breaking into houses to steal food.
STEVEN AINSWORTH: The fact that he's
eating food from the house, at the scene of these burglaries,
and you have Reese's Peanut Butter Cup wrappers
on the floor, all kind of point toward Mr. Dobson.
It's just logical you go look at him.
NARRATOR: But eating candy wouldn't be enough.
Investigators would need much more.
Some of Walter Yokum's neighbors told investigators
about some suspicious looking men in the neighborhood
on the night of Yokum's ***.
So they asked the neighbors to view a lineup that included
their prime suspect, James Dobson.
TONY MATTHEWS: Your witness look at them
and decide if any of them are the guy.
And in this case, I believe Mr. Dobson was
familiar to the witness but they couldn't say, that's the guy.
NARRATOR: Dobson denied any involvement in Yokum's ***,
and there was no evidence he owned a weapon capable
of firing of .38 caliber bullet.
And Dobson didn't own boots that matched
the impressions found at the crime scene.
So investigators wanted to know if there were fingerprints
on the peanut butter cup wrapper,
found next to Yokum's body.
DON SOLLARS: On processing that wrapper,
I was not able to obtain any latent
prints off of that surface.
NARRATOR: In fact, there were no foreign prints anywhere
in the house.
In order to identify more potential suspects,
Colorado investigators searched police records
to identify any unusual criminal activity
around the time of Walter Yokum's ***.
And one incident, in particular, stood out.
Two undercover officers noticed a pickup truck
with North Dakota license plates,
leaving the home of a known drug dealer on the day
after Yokum was killed.
The truck was registered to Kevin Dockter.
TRIP DEMUTH: So she called Bismarck, North Dakota,
to ask them about who is this Kevin Dockter guy.
TONY MATTHEWS: They said, well you
know it's funny you should call about him because we
just arrested him yesterday.
NARRATOR: 29-year-old Kevin Dockter was a career criminal
with a history of drugs and weapons offenses.
TONY MATTHEWS: They said he's a convicted felon,
so we arrested him for possession of weapons
by a previous offender.
And one thing led to another, and of course next question
is, well, what kind of guns did he have.
NARRATOR: When arrested, Dockter had a .356 and a World War II
era .45 caliber Colt pistol, like the one
missing from Walter Yokum's holster.
But that wasn't all.
STEVEN AINSWORTH: When Kevin was arrested, in addition to all
the other paraphernalia and things
like that, that were found in the car,
there was coincidentally, or not coincidentally,
a bag of Reese's Peanut Butter Cup miniatures.
The same type that were found at Mr. Yokum's residence.
TONY MATTHEWS: It's not a scientific thing,
but to me, if I was in a jury I would put a lot of stock
in this just because it makes sense.
NARRATOR: The .45 caliber pistol had the serial number scraped
off of it, just like Walter Yokum's gun.
And it had some ammunition in the clip.
Highly distinctive ammunition.
The base of the bullet was stamped
with the letters R-E-M-U-M-C.
TONY MATTHEWS: It's a Remington manufactured ammunition,
and UMC stands for Union Metallic cartridge.
I called up Remington.
And the guy who answers the phone says, oh yeah I've
worked here for 43 years.
That ammunition was made from 1912 to 1961.
NARRATOR: The same type of ammunition
was found in Walter Yokum's house.
He'd kept the gun and the bullets for almost 50 years.
TONY MATTHEWS: It's kind of winning
three numbers on a lottery ticket.
You can't go down to the hardware store or the gun store
and buy that ammunition.
NARRATOR: There were .38 caliber bullets in Dockter's .357,
which were subjected to inductively
coupled plasma emission spectroscopy.
JOHN KILTY: A bullet from the crime scene
was compared to the bullet from a cartridge
in Mr. Dockter's gun.
And three bullets from cartridges
that we recovered from his truck.
And they were found to be analytically
indistinguishable, that is they all
had the same composition of lead.
M. BONNER DENTON: Having two batches of lead that
are similar, the FBI rated that at about 1 in 2,500.
So as far circumstantial evidence, that's pretty good.
NARRATOR: Scientists went one step further.
Kevin Dockter was wearing work boots when he was arrested.
Impressions were made and compared
to plaster casts of bootprints found outside of Yokum's house.
The cast from the crime scene didn't have enough detail
to show any accidental characteristics, which
are marks that result from everyday wear and tear.
The class characteristics-- the size, the tread patterns,
and the manufacturing impressions--
were there for comparison.
DON SOLLARS: The overall characteristics
on the different casts were consistent with what
was present on the boots that were submitted.
NARRATOR: So the evidence against Kevin Dockter
was mounting.
He owned boots like the impressions at the crime scene.
He had the same taste in candy as the killer,
and had no explanation for why he was in possession
of Walter Yokum's gun and ammunition.
Kevin Dockter was the prime suspect
in the *** of Walter Yokum.
And apparently, he was a big talker.
Investigators spoke to Dockter's friends,
who said Dockter bragged about committing
a robbery in Colorado.
And said his friend, 21-year-old Jason Fowler,
acted as a look out.
STEVEN AINSWORTH: We went to Jason Fowler
and said, look we've, got another person
ready to give you guys up.
And you're going to go down do some hard time
in a mainline joint.
And he says, well OK, I think I'm ready to talk.
TRIP DEMUTH: Jason Fowler told us that he and Kevin Dockter
had a drug habit.
That they supported their drug habit by breaking into homes
and stealing items.
NARRATOR: Fowler told investigators
that he and Dockter cased Yokum's house.
Since no lights were on, they assumed no one was home.
Dockter left his boot impressions in the mud
as he broke the downstairs bedroom window.
The noise apparently woke Walter Yokum,
as he grabbed his World War II 45 pistol
and went to see what was going.
Dockter saw him first, and fired one shot
killing Yokum instantly.
Fowler says they left the scene and went to a local bar.
After several drinks, they decided
to return to Yokum's house two rob it.
Dockter ate the peanut butter cups
as he searched for items to steal.
He moved Yokum's body to look through his pockets
after rigor mortis set in.
All they took was $20 in cash, a credit card,
and Yokum's highly distinctive .45 caliber handgun.
JASON FOWLER: He pulled out a green .45--
TRIP DEMUTH: This truly was a senseless killing.
Not that there's any killing that make sense,
but this one was particularly senseless.
NARRATOR: The day after the ***, undercover officers
saw Kevin Dockter's truck leaving
the home of a known drug dealer.
It was the break investigators needed.
TONY MATTHEWS:Had they not gotten that license plate doing
that drug deal, we probably never would have had that name.
Certainly not as directly as we did.
NARRATOR: Kevin Dockter plead guilty to second-degree ***,
and was sentenced to 40 years in prison.
Jason Fowler plead guilty to burglary,
and was sentenced to 25 years in prison.
One final note.
It's easy to see why the neighbors first chose James
Dobson as the man they thought they saw near the crime scene.
Dobson bore a striking resemblance to Jason Fowler.
STEVEN AINSWORTH: Everybody that worked on this case,
are probably, in my opinion, the best there is.
And so it really didn't surprise me
when it went into the solved column,
because of the caliber of people that worked on it.
TRIP DEMUTH: It was just one of those cases
of excellent police work, and some luck,
and they'd all fallen together in a case that
easily could have gone unsolved.
And so, yeah, when I got done with it, and I look back on it,
I was kind of like wow!
I can't believe we actually were able to do that.