Evidence report

Download 19.03 Kb.
Size19.03 Kb.

Eli Cooper


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 ex-husband; 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.

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.


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 Anti-Rh 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.


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

Figure . Body Temperature
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 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

Figure . Gel Electrophoresis
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 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.


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.


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.

Share with your friends:

The database is protected by copyright ©essaydocs.org 2020
send message

    Main page