EVIDENCE REPORT
Eli Cooper
9/24/14
INTRODUCTION
On August 14, 2012, Anna Garcia, age 38, was found dead in her home at 9:56 a.m. The manner
of her death was unknown. The police located no witnesses. A neighbor of Anna called the
police to report that she did not respond to phone calls or the doorbell that morning and her dog
was barking very loudly for two hours. He reported that he had spoken to Anna the previous
morning around 6:30 a.m. and noted that while it was extremely hot outside, Anna was wearing a
sweater. The police found Garcia lying face down in the hallway. Authorities observed a pool of
blood around her head and some vomit beside her. It was 73 degrees inside Anna’s house, while
it was 92 degrees outside. Garcia was last seen alive by her former husband, Alex Garcia the
night before her death. The police identified four potential suspects: Alex Garcia, Anna’s exhusband; Erica Piedmont, Alex’s new wife; Lucy Leffingwell, Anna’s partner in business; and
Doug Greene, Anna’s neighbor and ex-boyfriend. The police contacted the team to aid in
determining the cause of Anna’s death and if any of the suspects were involved in her death. The
main question before the team is whether Anna Garcia’s death is a homicide, an accident,
suicide, or due to natural causes.
SUMMARY OF FINDINGS
A crime scene investigator collected evidence at the scene including fingerprints, blood samples,
shoeprint, hair, unknown substances, pills, and diameters of blood spatter. The team then
examined the information to determine if Anna Garcia’s death was a homicide, an accident,
suicide, or due to natural causes. The team processed the following evidence in an effort to
determine Anna’s cause of death and whether or not one or more of the potential suspects were
involved in her death. Analysis of each piece of evidence took the team one step closer to
figuring out how Anna died.
Blood
The crime scene investigator collected blood samples from the scene. The team compared the
type of the blood found at the scene with the blood of the suspects and victim to determine
whose blood was at the scene. The team examined the blood type by using Anti-A, Anti-B, and
Anti-Rh serum. We took samples of blood from the suspects and the deceased and mixed the
blood with these serums. If the blood clumps with the serum, then it is positive for that type of
blood. (PBS 2014) If Anti-A clumps then the blood was type A, if Anti-B clumps then the blood
was type B, if both clump then it was type AB, if neither clumped then it was type O, and if the
Anti-Rh clump then the blood type was positive. (PBS 2014) The team took each blood sample
and mixed it with each serum. We found that Anna’s blood clumped with the Anti-A and AntiRh serum. This means that she was A+. We also discovered that the blood at the scene clumped
the same way. None of the suspect’s blood clumped with just the Anti-A and Anti-Rh serum;
therefore, the blood found at the scene was Anna’s blood. The limitation of this method of
analysis of blood found at a crime scene is that many people have the same type of blood, so if
two of the people the team tested had the same blood type as the blood found at the crime scene,
this method would have been inconclusive.
Hair, Fingerprints, And Shoeprints
The team examined the hair, fingerprints, and shoeprints found at the scene. In analyzing the
hair found at the scene, the team compared the recovered hair from the scene to the hair of the
suspects and Anna. Upon examination, Anna Garcia’s hair matched the hair found at the scene.
An examination of the shoeprints required a comparison of the indentations and patterns of the
shoes. The pattern of Anna Garcia’s shoe matched the shoeprint located at the scene. Finally,
the fingerprint examination required an examination of the ridge pattern and the minutiae of each
person’s fingerprint. (PBS 2014) The fingerprint found at the crime scene was a plain type of
fingerprint and matched Alex Garcia’s fingerprint. Police initially reported that Alex Garcia went
to Anna Garcia’s house the night before her death to discuss some paperwork. Thus, the
fingerprint recovered was most likely from the night before when Alex was visiting Anna. So,
the identification of the other fingerprint at the scene did not conclusively point to foul play. In
fact, the team ultimately disregarded the fact his fingerprint was at the crime scene because of his
appointment with Anna the night before her death.
Pills
The team analyzed two unknown pills recovered from the crime scene to determine what type of
drug they were. It could have been Cocaine, Acetaminophen, Acetylsalicylic Acid (Aspirin),
Methamphetamine, or Ecstasy. To determine the identity of the two unknown pills, the team
crushed the unknown substance and the five possible substances into a powder and then mixed
each specific substance with three different indicators. (PBS 2014) These indicators reacted in
different ways with each of the different substances. The team observed the chemical reactions
with each indicator and compared the chemical reaction of the unknown pills to the reactions of
the known substances. The unknown pills and the aspirin had the same reactions with the three
indicators, so the unknown pills found in Anna Garcia’s home were aspirin. This method of
determining the unknown pills at the scene does have a potential limitation. Many substances can
have the same, or very similar, chemical makeup. If two substances had the same reactions as
the pills found at the crime scene, the team wouldn’t have been able to identify the unknown
pills. Also, there are many external factors that could have changed the reactions between the
indicators and the substances, so if a different team performed the same experiment with
different external factors the data would be inconsistent.
Time Of Death
Anna was found dead at 9:56 am, but most likely died earlier than that. To determine the time of
death, the team set up an experiment. We used logger-pro to measure the temperature of a body
clock in two different temperatures of water: really cold ice water to simulate a cold room and
regular room temperature water to
simulate a normal room. The team
determined that the colder the
room was the faster body
temperature decreased. As you can
see in Figure 1, the cold
temperature (the bottom line)
decreased more rapidly than the
room temperature (the top line).
The limitation of this experiment is
that the experiment is greatly
Figure 1. Body Temperature
affected by temperature. If the body clock, room temperature, or water temperature was
different, then the data could be altered or inconsistent.
The team then used an equation called the Glaister equation to determine the exact time of
Anna’s death. The Glaister equation is 98.4 minus the measured rectal temperature divided by
1.5. (PBS 2014) A deceased individual’s body loses heat at a rate of 1.5 degrees per hour until
the body reaches the temperature of the environment, in our case the room. We then determined
that Anna died at 7:00 a.m. the morning of August 14, 2012.
Blood Spatter
The blood also provided the team with a determination of whether Anna fell and what height she
fell. (PBS 2014) Blood spatter analysis pattern can also assist the team in determining whether
Anna’s death was an accident or a product of foul play. (PBS 2014) The team conducted an
experiment to determine the effect of height on blood spatter diameter. We dropped small
amounts of fake blood from different heights and measured the diameter. We dropped it from
height between 1 cm and 200 cm. We determined that as the height increased the diameter
increased, but not by much. The differences were very small. After analyzing the data obtained
from the experiment and comparing it to the size of the blood spatters found at the scene, the
team determined that Anna was sitting when she fell and hit her head on the table. (PBS 2014)
The limitation of this method is that even a small error can cause the results to be inaccurate. If
you make a mistake in the procedure at any time, the data could be different. For example, at the
end of our individual blood spatter experiment, the team compiled the graphs of all the data from
the different groups, and we had two lines of best fit. The results from the different teams
demonstrate that there were a few groups that made a mistake and that means this data could be
inconsistent from group to group.
DNA Fingerprinting
DNA fingerprinting is utilized to determine who was at a crime or who the victim was. You have
to do everything very carefully because if you mess up at the beginning you won’t get results in
the end. There are six steps. (PBS 2014) The first step is obtaining a genetic sample. (PBS 2014)
Your sample has to be well preserved and not damaged. This ensures that the results are valid.
(PBS 2014) Step two is extracting the DNA from the sample. (PBS 2014) This is where
following directions is crucial. To extract DNA you first have to “crush” up the sample until it is
in liquid form (unless already in liquid form). Then you add cold ethanol to the top of the sample
and look for the DNA. The ethanol works because ethanol is positively charged, but the DNA is
negatively charged. This means the DNA is
attracted to the ethanol. (PBS 2014) Step three is
amplifying your newly extracted DNA. (PBS
2014) You do this by using a process called
Polymerase Chain Reaction (PCR). PCR happens
in three steps. First is denaturing which is where
the double helix shaped DNA is “unzipped.”
Second is annealing, which is where different
primers match up to their corresponding parts of
DNA. Third is extension where the rest of the
DNA is filled in. (PBS 2014) After PCR you
have enough DNA to get some answers. Step 4 is
to “cut” the DNA using Restriction Enzymes.
The Restriction Enzymes cut the DNA in certain
places to create Restriction Fragment Length
Polymorphisms (RFLP’s) which are used in the
next step. (PBS 2014) Step 5 is Gel
Electrophoresis. This is where the DNA is placed
Figure 2. Gel Electrophoresis
into a gel and then a current is run through that gel. The RFLP’s move down the gel at different
speeds. The longer the RFLP the slower it moves, and the shorter it is the faster it moves. This
difference in speed causes the RFLPs to move different distances. (PBS 2014) Then step 6 is to
analyze the results.
The team utilized DNA fingerprinting because we found blood and other genetic containing
samples at the scene. The team examined DNA from the scene and DNA from the victim and
suspects and put them through this process. What happens is that the RFLPs of the DNA found at
the scene and one of the other five people we were testing should end up traveling the same
distance because the DNA would be the same. As you can see in Figure 2, Anna’s DNA ended
up being the same as the DNA found at the scene.
Autopsy
An autopsy is an examination of a body after death to determine the cause of death. An autopsy
of Anna’s body was conducted. The team was provided a partial autopsy report for Anna. This
autopsy told us some things we already knew and some things that change our hypothesis. The
team learned that Anna was taking aspirin, but that it was not an over dosage. The blood that was
found at the scene had come from an open wound on her right temple. We also confirmed that
she threw up on herself before death. The autopsy report revealed that Anna’s ankles and
abdomen were swollen. Also, her fingernails were gray which hinted of oxygen deprivation
before death. Furthermore, she had recently healed broken bones. Lastly, she had inflamed
injection sites on her left thigh.
CONCLUSION
The question presented to the team is whether Anna Garcia’s death was a homicide, accident,
suicide, of natural causes, or undetermined. A review of the evidence suggests that Anna Garcia
died of natural causes. The blood found at the scene matched that of Anna Garcia. The hair and
shoeprint located at the scene was also that of Anna Garcia. While the fingerprint of Alex Garcia
was located at the scene, the record reflects that he had been in the home the night prior to her
death to go over some paperwork. The pills located at the scene were aspirin. The approximate
time of death of Anna Garcia was 7:00 a.m. The time of death is corroborated by the fact that
the neighbor had heard the dog barking for approximately two hours. The blood spatter analysis
indicated that Anna Garcia was sitting in a chair when she fell and hit her head. The blood and
other genetic material found at the scene matched Anna Garcia and none of the other suspects.
Considering the fact that the blood, DNA, hair, and shoeprint matched Anna Garcia, the evidence
points to Anna being the only person in the house. Thus, the evidence rules out homicide.
Additionally, suicide has also been ruled out. The autopsy does not reflect any means of suicide
either ingested or external. Instead, the evidence shows that she was sitting down, perhaps lost
consciousness, fell, and hit her head.
I believe that Anna died naturally. She most likely had a headache because she was taking
aspirin. She also threw up on herself before she died. She was suffering from oxygen deprivation
as well, which showed in the grayness of her fingernails. She could have died because of a fatal
illness like MRSA or another bacterial infection. The injection site and the water retention could
also suggest that she was suffering from a long-term illness as well.