00:00:05
[Music] early one morning in a deserted area outside of Phoenix a motorcyclist discovered the body of a young woman she
00:00:15
had been beaten bound strangled and possibly raped the surrounding plants would tell
00:00:23
more about her killer than any other single piece of evidence [Music] [Music] when investigators from the sheriff's
00:01:04
department arrived at the crime scene they gathered every possible piece of evidence the victim was nuded except for
00:01:11
a pulled up tank top and a t-shirt wrapped around her neck which was probably used to strangle her her wrists
00:01:20
and ankles were Loosely bound with shoelaces and what looked like picture hanging wire nearby investigators found
00:01:29
a ringe some articles of clothing then they heard some evidence it was a pager found deep in
00:01:48
the grass a few feet from the body the discovery of the pager triggered a larger search and the
00:01:56
photographer took some aerial photographs there appeared to be a circular area of matted grass where an
00:02:03
altercation possibly took [Music] place police took the victim's remains to the medical examiner for
00:02:17
identification and autopsy a fingerprint search identified the victim as 30-year-old Denise Johnson
00:02:25
a single mother of two young children she was born and raised in an area of Phoenix known as the projects she wasn't
00:02:34
a bad girl she some of her friends I think she got with the wrong friends I ain't going to say they made
00:02:42
her do these things now she hung around with people that like to party drink and I don't really
00:02:50
know what they were doing but she you know she was out there in the world with people that did drugs I'm sure and
00:02:58
sometimes I think she trust it too much Denise made her living on the streets of
00:03:03
Phoenix she had a history of short changing truck drivers in various drug deals at local truck stops which earned
00:03:10
her the nickname twist Mama her friends cautioned her that her lifestyle was probably going to find her in a lot of
00:03:18
trouble someday and eventually it did but who ended Denise Johnson's life the
00:03:26
investigation began with the pager found lying near the body it belonged to this man a local trucker
00:03:32
named Mark Bogan he said that on his way home from work the night before he stopped to make
00:03:40
a phone call that's when he met Denise Johnson for the first time hi how you
00:03:45
doing hello there boken said she asked for a ride to the interstate why not thanks once inside the truck she made
00:03:56
some sexual advances they pulled off the road and had sensual sex in the cab of his
00:04:05
[Music] truck afterwards as he was dropping her off he said she attempted to steal some
00:04:15
of his things off the dashboard oh I had a really good time so did I baby did you
00:04:21
oh always when I'm in the company of a lovely lady I would really love to have my
00:04:27
wallet back after a brief scuffle he retre his wallet she got out and left on foot Lan said that was the last he saw
00:04:36
of her the next morning he noticed his pager was missing assumed he had lost it and called the pager company to report
00:04:44
it missing during the interrogation of Mark Bogan investigators noticed scratch marks on the side of his face if there
00:04:53
were scratches on the suspect's face then you would expect that if those were
00:04:57
in fact inflicted by things fers or fingernails of the victim there should be some residue of either the skin cells
00:05:04
and or maybe even blood under the fingernails the autopsy of Denise Johnson revealed no skin or blood under
00:05:10
any of her fingernails the medical examiner found that Denise Johnson's death was caused
00:05:16
by asphixiation due to strangulation blood test showed cocaine in her system however there were no
00:05:25
signs of any type of sexual activity there was no seen found no foreign hair clothing fibers or saliva found anywhere
00:05:33
on her body the autopsy told investigators how Denise Johnson died but provided no clues about her killer
00:05:44
their one suspect Mark Bogan was apparently a dead end the Sheriff's Office had not only a murder but a
00:05:57
Myster on the day after police discovered Denise Johnson's body homicide detective Charlie Norton was
00:06:03
assigned to the case I decided that it would help me as the investigator to go out and familiarize myself with the
00:06:11
scene where the body was found Denise Johnson's body was discovered in a remote part of Maricopa County about a
00:06:19
half an hour away from Downtown Phoenix Charlie Norton was looking for anything out of place or unusual
00:06:27
anything that might have been overlooked the day before then he saw it something peculiar
00:06:34
on a Palo Verde tree just a few feet from where the body was found I had parked my car on the pavement I noticed
00:06:42
that there was a a branch that was hanging over um and when I looked at that Branch I noticed that there was a
00:06:50
fresh abrasion and I had no idea what it might mean but I took a picture of it then I took some beans off of that
00:07:00
particular tree meanwhile investigators confiscated Mark Ban's truck to look for
00:07:05
possible evidence linking him or his truck to the crime scene it was completely clean no fingerprints semen
00:07:13
blood saliva hair or clothing fibers no evidence at all that Denise Johnson was even in the
00:07:21
truck but when investigators and police photographers looked in the back of the truck they made an interesting discovery
00:07:29
they found two bean pods from a poo Verde tree was it possible that Ban's truck
00:07:38
brushed against the Palo Verde tree at the crime scene causing two bean pods to drop into the back of the truck the
00:07:46
problem was Palo Verde trees are very common in Arizona there are tens of thousands of them in the Phoenix area
00:07:54
alone but Charlie Norton's boss had an idea to see if DNA test Tes in could match the bean pods from Ban's truck to
00:08:03
the tree with the abrasion at the crime scene I suggested to Charley at the time
00:08:08
I said you know I said it'd be a real good idea if we could find someone somewhere as in the United States that
00:08:16
is involved in DNA testing the plant life and I said what the hell have we got to lose you know where are we going
00:08:21
to go from here what's the number for ID Norton started working the phones calling scientists all over the United
00:08:28
States yeah got uh answers like it couldn't be done to maybe it could be done and that if it could be done that
00:08:36
the cost would be prohibitive 15 telephone calls later he found someone who offered some hope ironically just
00:08:44
100 miles away at the University of Arizona in Tucson I saw that as sort of a public service thing that we could do
00:08:51
that we'd show some of this science as relevant to people in May maybe a way
00:08:55
that's not quite as obvious sometimes through agriculture could DNA really showed that one plant or tree was
00:09:02
different from another even though they were the same species DNA is present in all cells of all living things it's a
00:09:09
little like a computer program containing all of the information necessary to create a living thing all
00:09:17
humans have different DNA profiles except for identical twins in the early 1980s Dr Alec Jeff a
00:09:26
British scientist discovered a test that made it possible possible to identify an
00:09:30
individual's DNA profile jeffy's breakthrough technique was first used in
00:09:36
a criminal case in 1986 but plant DNA had never been used in a criminal case And scientists
00:09:45
weren't even sure they could figure out a way to extract DNA from the Palo Verde
00:09:50
seed pods well we certainly use fingerprinting a lot in agriculture but we'd never looked at this particular
00:09:56
species uh this tree nobody has probably ever done in biology on it at all prosecutors had circumstantial evidence
00:10:03
linking Mark Bogan to Denise Johnson's murder but they needed something more
00:10:09
definitive they knew they would have to prove that Bogan was at the crime scene and the Palo Verde pods were their best
00:10:18
chance the scientists had no idea that their research would be the Cornerstone of a murder
00:10:27
case the Arizona Sheriff Department wanted to know if there was any way scientists could match the two seed pods
00:10:34
found in the back of Mark Ban's truck to the Palo Verde tree next to where they
00:10:39
discovered Denise Johnson's body but there were thousands of Palo Verde trees in the Phoenix area alone
00:10:47
and there had never been a DNA test on this type of tree we had to learn how to do the analysis so that we could say do
00:10:55
trees look different from each other in this species because what we wanted to know was not was this a palty tree but
00:11:01
can I match it to that specific tree Dr Helen jarus used what is known as a randomly Amplified polymorphic DNA
00:11:09
technique or rapid this is a less common test than rflp the one used in searches
00:11:16
for human DNA one of the great things about Rapids is is that you're able to know nothing
00:11:22
about an individual species or type of organism you don't have to have any prior knowledge about it all you have to
00:11:28
do is get DNA and the method works the test begins by removing the beans from their hard outer shell or pod the seeds
00:11:36
have DNA both from the mother tree and other trees that would have pollinated it so we need to get rid of those and
00:11:42
just use the pot material which will only have DNA from the mother tree the shells are put into liquid nitrogen
00:11:48
making them brittle and easier to grind into a fine powder a chem chemical solution is added
00:12:00
and the DNA floats free a sticky bundle of complex molecules the sample amount of DNA from
00:12:08
a seed pod is too small for analysis so scientists increase the sample size by copying the DNA strand they use a
00:12:18
technique called polymerase Chain Reaction or PCR the copying process takes place in a
00:12:25
DNA thermal cycler within a few hours this technique multiplies the DNA millions of times the DNA is then placed
00:12:35
into various Lanes of a gel with a Dy added and then subjected to an electrical field under ultraviolet light it's
00:12:45
possible to see how the electrical current draws the negatively charged fragments through the gel to the
00:12:51
positive end at the top the results resemble a bar code the genetic fingerprint of a Pao Verde
00:13:03
tree these fingerprints enabled Helen Jaris to make an important Discovery the two pods found in Mark Ban's truck
00:13:12
matched each other and they also matched the pods taken from the tree at the crime scene the tree next to where
00:13:20
Denise Johnson's body was discovered every other Palo Verde tree tested had a
00:13:26
completely different DNA profile it was the result that investigators and the district attorney had hoped for it
00:13:34
wasn't the criminal itself but it was a particular tree that we had to identify
00:13:37
and in fact they had matched we had matched that up he was able to take the original samples take a part
00:13:46
of the samples from the pickup truck determined that those two pods came from the very same tree then he compared
00:13:56
those with all samples from all 12 Trees in matched it to a tree there at the crime scene not knowing that the tree
00:14:05
had the scrape on it to which he matched it but there were only 12 Trees in the initial test and the prosecution felt
00:14:13
that wasn't a large enough sample they needed to show a potential judge and jury that all of the Palo Verde trees in
00:14:20
Arizona had a different DNA profile so the district attorney sent Helen jarus pods from 100 different
00:14:29
trees asking him to prove that each had a separate and distinct DNA profile and he tried to trick Helen Jaris I did not
00:14:39
tell Dr Helen jarus that I had gone back out to the scene had a deputy take a sample from the same tree which had the
00:14:47
scrape on it Dr Helen jarus proved that each of the pods had a different DNA profile and he also discovered the
00:14:56
prosecution's trick I called him and I was a little concerned because uh you
00:15:00
know well we could tell all these trees apart and so forth but we put the sample
00:15:04
back in and it looked like it matched one of these supposedly random trees that they'd gone out and done it's
00:15:09
almost like a touchdown in the endzone I knew it I knew he had hit on it out of 20 other samples that he had tested on
00:15:16
one Gil he hit and matched perfectly police arrested Mark Bogan and charged him for the murder of Denise Johnson he
00:15:25
entered a plea of not guilty but the question remained would this new DNA evidence be admissible in court no one
00:15:36
had ever introduced plant DNA as evidence in a criminal trial anywhere we held a preliminary hearing before the
00:15:43
judge only to review the scientific evidence to see whether or not it was evidence that was generally accepted in
00:15:51
the scientific Community as both valid and reliable for 3 days without a jury on hand lawyers and scientists argued
00:15:59
whether plant DNA should be admitted into a criminal trial for the first time ever what all of the scientists agreed
00:16:07
about was that plant DNA like human DNA was unique to each plant and if properly
00:16:17
tested could distinguish one palty tree from another palver tree and there seemed to be no dispute about that judge
00:16:26
Bolton denied the defense motion to prohibit Dr Helen Jar's testimony thereby allowing the DNA evidence to be
00:16:34
admitted at the trial in setting a precedent judge Bolton had made DNA history we were the first criminal case
00:16:44
in the country that used a DNA comparison of plant material to uh as a piece of evidence now armed with the
00:16:54
potent weapon of a DNA fingerprint the prosecution went to trial attempting to prove to a jury that Mark
00:17:02
ban murdered Denise Johnson what happened to Denise Johnson on the night of May 2nd
00:17:12
1992 the prosecution believed that Mark Bogan met Denise Johnson at a phone booth hi how you doing they spoke
00:17:21
briefly and Denise asked for a ride sure why not thanks [Music] they drove to a deserted location for
00:17:37
what was going to be a consensual sexual [Music] encounter how would you like to have
00:17:51
some real funan asked Denise if she would agree to some light bondage and tied her wrists and ankles with some
00:17:59
picture frame wire and shoelaces some of Ban's ex-girlfriends would testify that he enjoyed bondage
00:18:08
and another witness told investigators that she saw the same type of wire in the cab of his truck just a few days
00:18:16
earlier no no stop it at some point Denise Johnson objected to what was happening and asked Bogan to stop
00:18:25
Johnson got out of the truck and tried to run with fast behind quickly the situation turned violent the two
00:18:34
struggled in the open field Bogan lost the pager he carried on his waist which fell into the high grass Bogan strangled
00:18:43
Johnson with her own t-shirt then he dragged her body under some nearby bushes and
00:18:50
left as Bogan drove away his truck brushed against a Palo Verde tree leaving the abrasion two seat ODS
00:18:59
dropped into the back of his truck an eyewitness saw a white truck similar to the one Bogen own coming out
00:19:09
of the road leading from the crime scene going through a stop sign and speeding off in the direction of Phoenix the
00:19:16
witness said it was about 1:30 in the morning Bogan lived 18 minutes from the area and his wife told police she awoke
00:19:24
as Mark returned home just after 2: in the morning most of the evidence against Mark Bogan was circumstantial the Lost
00:19:33
beeper the picture frame wire his interest in bondage and the witness who saw a white truck in the vicinity of the
00:19:41
crime scene the night of the murder but the most critical evidence in the case was the plant DNA there wasn't a
00:19:50
fingerprint there wasn't a drop of blood there wasn't a hair there were none of
00:19:55
those things that anybody could say were part of the victim's body found must
00:20:01
have been left by the victim on the defendant or on the defendant's property
00:20:07
or vice versa he had admitted to the detectives that he'd washed his truck the next morning he got rid of all of
00:20:13
the evidence in the truck except for two Pala verti pods they needed evidence that placed Mark at the scene uh cuz he
00:20:21
did have a credible story as a prosecutor I had a mantle of evidence that I wanted to place upon the
00:20:26
shoulders of the defendant the palti pods and took the mantle by the drawring and wrapped it around his neck unable to
00:20:37
challenge Dr Helen Jar's findings themselves the defense challenged the evidence implying the pods were planted
00:20:45
in the back of Mark's truck but investigators said the seed pods were found in Ban's truck before samples were
00:20:52
taken from the crime scene if I was going to plant evidence I would plant something that that I
00:20:59
know that I could match later on and and probably be a little bit more uh assured of a conviction the jury
00:21:10
found Mark Bogan guilty of murder in the first degree he was sentenced to life in
00:21:17
prison without parole for at least 25 years the appell at court upheld the verdict Mark Bogan continues to maintain
00:21:26
his innocence and the appeal process is continuing I'm trying to forget this
00:21:31
case cuz I'm the only person on the planet that lost to a plan it was something that hadn't been
00:21:37
done before uh something that was certainly very different from the routine things that we do every day as
00:21:47
judges but I love my daughter very much I love all my children but it's something we just have
00:21:55
to go through it's done I don't know what in the world that could have tripped him off to to hurt her like that
00:22:04
I don't know but I hope one day we'll find out [Music] a [Music]