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[Music] most homeowners would prefer grass to a lawn full of weeds but the forensic scientists weeds can
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tell a story with the help of a plant biologist and a new high-tech computer program
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investigators solved the mystery of a young girl's murder [Music] weekends were typically busy in the
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mauser household one saturday morning in 1995 as kathy mouser was leaving for work she reminded
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her 14 year old daughter jenna that she was grounded for the weekend and wasn't
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allowed to use the telephone either jenna was having some behavioral issues a lot of 14 year olds 15 year olds might
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have those kinds of issues when they're growing up lots of pressure social pressures problems within the family
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she was having such trouble that the family was taking her to counseling kathy returned home from work around 1pm
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and as soon as she tried to open the door she knew something was wrong mrs mauser found the front door lock
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which she said was unusual because usually there's there's somebody there
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and she was expecting jenna to be there so the front door would have been unlocked
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jenna wasn't home and she hadn't left the note saying where she went they just figured she was upset and she
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would basically just walked away you know or she was just with one of her friends or
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yeah none of the neighbors saw jenna leave or noticed anything suspicious when jenna's stepfather and brother
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arrived home several hours later they searched the neighborhood and called all her friends
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but no one knew where jenna was later that night the mousers called police to report their daughter missing
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the next morning the mousers learned that the nude body of a teenaged girl was discovered in a ditch about 20 miles
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outside of town the family identified jenna's body at the morgue the reality of
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her being murdered rather than an accident or it didn't hit me i didn't understand
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really that that something like that could happen in my life it was it was hard to deal with
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and and to it was just such an unfair act and i couldn't couldn't understand it
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for a long time the coroner identified the cause of death as strangulation there were other injuries as well
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in addition to the ligature strangulation marks she also had evidence of blunt force injury to the
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head she had received a blow to the head in the left forehead area and the left temple
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there were no defensive wounds and no signs of sexual assault the scalp here is brown about 14 inches in length
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well the soles of the feet were clean in this case and that indicates to me that
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she certainly was not standing up at the scene where she was found and she certainly did not walk
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there the only other findings were some unusual marks on jenna's thigh indentations that were made
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after death on a living person these fade very quickly in this case these are postmortem
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pressure marks they don't tend to fade because the the color comes as the blood leaks out
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of the vessels by gravity after death and it more or less outlines the area of pressure and then it stays that way
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indefinitely until the body decomposes the mouser's telephone records yielded
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the first clue despite the fact jenna was told not to use the telephone she called several
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friends that morning yeah you should talk to him really senior well you'll see on monday
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around 11 30 jenna's conversation with her friend ended abruptly hello jenna
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jenna one of the last people that she speaks with says that the phone goes dead jenna
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doesn't call back the friend pages her a couple of times jenna never calls back
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police found jenna's diary in her bedroom which had an entry from the morning of
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her murder dear journal sorry i haven't written you but i've been pretty busy
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things have been going pretty good at school except for the fact that guys don't even know i'm alive half the time
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the diary expressed a specific interest in two boys one was considerably older than jenna a
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boy she met at a local amusement park he was a young man about 18 or 19 years old
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who was preying on children that were not age appropriate he was older than us um
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not not the best kind of person that you'd probably want to want to be with but
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he there was something that she saw on him that attracted her to him investigators needed to start checking
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alibis and there was one that almost defied belief [Music] the mauser family had planned a
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traditional funeral service for their fourteen-year-old daughter jenna until her friend sarah hollander told
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them about a conversation the two once had about funerals we got on the topic of funerals and she did not want her
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funeral to be a sad thing she doesn't like it when people are sad she loves to make people happy
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she loves to make people laugh and so she definitely did not want her funeral to
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to portray something that she wasn't about so the mousers allowed sarah to help
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plan the funeral service one that was closer to jenna's wishes doug mouser took his stepdaughter's
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death particularly hard he had raised jenna since she was two years old and treated her like his own
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she truly did have a great relationship with him and loved him and he loved her he was very active in her life
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in the search for jenna's killer investigators looked inside the mousers home
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but found no clues everything was basically in its place nothing knocked over or anything to
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indicate that that jenna was fighting and screaming as she went out the door this raised the possibility that jenna
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left home voluntarily what the sheriff's department did was try and identify any boys she might have
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known or maybe if um boy she might have left the house with even though she was grounded maybe she'd get in a car with
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them and drive away police were able to identify the two boys jenna mentioned in her diary both
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had alibis for the day of the murder so police turned their attention to the whereabouts of janna's family members
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jenna's 18-year-old brother jaron had a solid alibi neighbors have him placed there for an
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hour hour and a half or so and that's the time period where jenna disappears
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jenna's mother kathy was teaching an aerobics class at the local gym so her alibi checked out too
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jenna's stepfather doug said he went to work for a few hours when police tried to verify his alibi
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they discovered the security cameras at doug's office were turned off that day
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when he went into the lab he's got to go through a security gate where all the
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cars that are coming in are cleared initially the person who was in the booth at the time said they didn't
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remember seeing him or his car come through doug mauser could give no description of the security guard and
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for a man who'd worked at the lab for a number of years you would think he would
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know the security guards remember them be able to give some description he could not so doug provided a second
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alibi that he bought lunch at a local fast food restaurant coincidentally the restaurant's security cameras
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weren't working either if he didn't have bad luck he would have no luck at all
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i can't really imagine you going into places that are supposed to have video cameras and none of them
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record you it was sort of exasperating because of snafu's if you will you know
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we didn't have any tapes we didn't have any solid stuff to show that he was
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there when police looked in doug's car they found no blood or any evidence suggesting foul play
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and there was no evidence the car had recently been cleaned but underneath the car
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investigators found something trapped in the undercarriage there was a significant quantity of this
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dried plant material some of it very large pieces and those were removed and analyzed later but
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had this plant material been there for weeks it you certainly wouldn't expect
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to find such large pieces of it still attached to the undercarriage could these dried weeds tell
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investigators anything about jenna's murder doug mouser told police he was the last
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person to leave the house on the morning his stepdaughter went missing he claimed jenna was cleaning her
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bedroom and he left there was no physical evidence that linked him you know like hair samples or dna or
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anything like that there were no physical evidence none there was zippo zero nil nada
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nothing yet investigators found some suspicious plant material underneath doug's car
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which they sent to forensic botanist dr fred ruscha he identified the usual specimens you'd expect to find
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underneath the car grass dirt and debris but he also found large quantities of yellow star thistle
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a weed i saw the yellow star thistle and then i saw the small scraps that had been taken
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off the body and i was able to compare that to material that had been collected from the area around the body and also
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from the trees that were in the overstory above the canyon where the body was found
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dr russia was looking for what botanists call diagnostic characteristics unique aspects of the plant that differentiate
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it from others of the same species every plant has a life cycle and a life sequence
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early in the season they look different than they do late in the season and prior to
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death plant materials all species go through a sequence of developmental events dr ruscha discovered the star thistle
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under doug mauser's car was identical in development to the star thistle found near janna's body
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while this was significant it wasn't enough to tie doug mouser to the murder
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yellow star thistle is not a rare plant it is an extremely common plant so in any given area of especially of northern
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california you in low elevations a yellow star thistle could be there you can't show that the evidence that
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was found underneath his car came from the crime scene it's too common in california and that
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with the other flora under the car it shows that he's been off-road so he could have picked it up anywhere
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investigators agreed so they turned their attention to the linear marks found on jenna's
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thigh the marks were made by a man-made object they were clearly of a shape and appearance that would not
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be normally found in nature while looking inside doug mauser's car detective bosma thought he found what
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caused them the hair on the back of your neck stands up and you're going this could be the
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mark of one of the marks on her leg but he didn't tell anyone about his discovery instead he sent photographs of
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jenna's skin marks to gary robertson a pioneer in the field of photogrammetry
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to see what he thought might have caused them robertson wanted to identify the exact size of the marks down to the
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micro millimeter so he scanned every autopsy photograph of the marks which enabled him to create
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a three-dimensional model we're extracting a measurement say from the left photograph extracting it from
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the right photograph and the computer software merges that into a three-dimensional measurement or a model
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that we can extract and do later judging from the size and shape robertson suspected that at least one of
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the marks was caused by the top part of a seat belt buckle this was precisely what hans bosma
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thought too but he wanted robertson's independent analysis well normally i don't have any
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information so i wasn't aware of anything about the vehicle next robertson flew to modesto
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california to conduct an experiment in doug mauser's car he wanted to try to
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recreate the same skin pattern that was on jenna's thigh he placed a live model the same height
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and weight as jenna in the back seat of the vehicle over the rear seat belt buckle
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it was a hatchback and one of the back seats was broken and was kept flat the model remained in the same position
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for 15 minutes the time it would have taken to drive from jenna's house to the dump site
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when the model was photographed robertson and bosma discovered what caused the other mark on jenna's
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leg when he placed her in there the there's carpet on the back of that that seat back because it lays flat so you
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have a nice carpeted area the carpet bead folds over as he pulls or pushes her over that particular area
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and that carpet bead was what one of the indentations were on on her leg just to make sure
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robertson put the model's pictures into his computer and compared them to the
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marks on jenna's leg it was a virtual match the beating which would cause the imprint on the
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model and on the victim's leg match precisely down to microns the width of the carpet
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and the orientation in that matched as well also the length matched interestingly
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the ripped carpet in the back seat of doug's car was unusual something you wouldn't find in other cars when he came
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back and said you know it's a match boy we were just ecstatic we finally gonna be able to nail this guy now we
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got him because now we can put jen in that car all the pieces fit together only one way and that's
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showing doug mouser guilty of killing jenna they didn't feel right excuse me
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they didn't theorize i'll say that on the screen i'd even say it in a courtroom they didn't have
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any theory other than he threw the body he killed her and threw it over the side
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and that she was in his car because of the mark on her leg that's all there was
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based on the forensic botany and photogrammetry doug mouser was arrested and charged
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with his step-daughter's murder prosecutors wondered what motivated doug mouser to kill his
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fourteen-year-old step-daughter jenna how can you possibly imagine someone doing something so horrible
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i can't imagine it but it happens unfortunately all the time prosecutors found evidence that jenna
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didn't always do what her parents asked she saw a counselor with some regularity
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she had oppositional defiant disorder that she was very defiant very aggressive very
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confrontational with family with parents the mousers telephone records provided a possible clue
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hey what are you doing i just got back from the mall with annie on the morning of her death
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jenna was on the telephone violating her parents rules his name's scott riley is
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a senior prosecutors believe doug caught jenna on the phone lost his temper and struck her
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hello jenna prosecutors believe doug's impulsive act of violence threatened his
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career he couldn't risk an allegation that he had hit her struck her he was working at lawrence livermore lab and he
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had a security clearance so any kind of a criminal conviction on his record would have been very difficult for him
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and put his job in jeopardy with jenna unconscious and not sure what to do prosecutors think doug panicked
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and strangled her to death he removed jenna's clothing to eliminate possible trace evidence
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when doug pushed jenna's body into the back seat of his car he displaced the carpet
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the underside of the carpet and the seat belt buckle left signature marks on her
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skin that wouldn't disappear since there was no blood flow doug chose a dump site 15 minutes away
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pulled his car off the road which picked up the bits of star thistle the same stage of development that was
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found on jenna's body [Applause] [Music] prosecutors think doug simply got lucky
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when the security cameras at both his office and the fast food restaurant weren't working
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but doug made a crucial mistake during his interrogation he said he used his computer that
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saturday at the office but his employer found no evidence that doug logged in they couldn't find any evidence
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whatsoever that he had done to his computers what he said he did basically we caught him
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we caught him in a lie doug mouser was tried and convicted of second-degree murder and sentenced to 15
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years to life in prison he continues to maintain his innocence ice for me this is the greatest failure
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of my life the only way i live with this situation is that i did the best that i could
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i did everything that i could think possible definitely uh jekyll and hyde personality there yeah one moment he's
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he's mr calm and cool and the next moment he's seen something totally different
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i think she would be really happy to know that that people love her so much to to fight
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to find the real answers to really what happened to her and she would be happy to know that we
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haven't forgotten about her the case against mouser was largely circumstantial
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but the photogrammetry helped convince the jury photogrammetry was the key element
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and it was used to solve the case and without photogrammetry this case would have gone unsolved
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