Crime Scene Investigation
November 3, 2014- December 2, 2014
Throughout the course of a month, a portion of our class time was dedicated to 'solving' a crime case. Several different pieces of evidence was presented and each group of detectives had the task of using scientific means to gather enough correct data to obtain an arrest warrant for the subject that we found guilty. We used chromatography tests, blood type samples, karyotypes, pedigrees, DNA, fingerprints, and family relations to draw connections between the crime, victim, and suspects. During the time period, our class studied the meticulous process forensic scientist go through for each investigation and the methods of solving for the unknown variable through several different mediums. It opened my mind to a unique possibility for a future profession and introduced me to new options of study.
Karyotype: A karyotype is the layout of a person's chromosomes to find any genetic related disorders. There were seven sets of DNA in total: one from each suspect and two different traces from the crime scene. The crime scene patterns were unknown and matched up to two of the dinner party attendees. The chromosome sets of one person was scattered on a piece of paper, completely randomly. In order to be able to comprehend the data, our group needed to cut out all the single chromosomes and pair them with by the corresponding number and size. These separated papers were then glued into order so any abnormalities could easily be recognized. Several people had matching chromosomal layouts, some matched the crime scenes, and some people had mental or physical genetic disorders. *See the chart in the forensic report at the bottom for a more detailed compilation of the data and research.
Chromatography: The purpose of using chromatography is to separate mixtures by placing it in a substance. In this case[literally a crime case:)], we used an alcohol solution to move spots of ink. In our set of evidence, there was a threatening message that plotted the murder of the victim, but the type of pen used was unknown. In this section of our project, we were able to compare the ink used in the message to three different types of typical pens that included a sharpie, ball point, and Crayola marker. By comparing the height the ink rose and the coloring and stains of each pen type we were able to deduce the type of pen. Then, we found the suspects that were in possession of the pen type and it corresponded with our existing suspicions. *See the chart in the forensic report at the bottom for a more detailed compilation of the data and research.
DNA Analysis: On of the tests to match the suspects and the crime scene evidence was to complete an analysis of DNA. In our project, we used gel electrophoresis to compare the lengths of each person's DNA strands. Gel electrophoresis works by sending electricity through an agarose gel that is submerged in a buffer. This makes the loaded dyes move along the gel. Each substance is separated by size because it takes longer for the larger particles to move so they will be located closer to the loading wells. This means the smaller particles that travel faster move closer to the bottom of the sample. From the coloring of the stains and the size of the particles, we were able to determine which two people had DNA found at the crime scene. *See the chart in the forensic report at the bottom for a more detailed compilation of the data and research.
Fingerprint: Prior to actually taking data from the crime scene, we learned about identifying different varieties of fingerprints. The ridges in people's fingers are intended for providing better haptic and allowing texture to be felt; however, each person on the planet has a unique set of fingerprints due to the shifts in genetics while developing. As a project, we first tested our own fingerprints to determine if each finger had the same type of ridges. The shape of each design varies between an arch, a loop, and a whorl depending on the dominant and recessive genes. We used tape and florescent dusting powder to take fingerprints of the knife found at the crime scene. This print was then compared to the already known prints of the suspects. *See the chart in the forensic report at the bottom for a more detailed compilation of the data and research.
Blood Types: Another project we completed to gather more evidence was testing the blood types of each suspect and comparing it to the traces of blood found at the crime scene. We mixed solutions together and if the mixture clotted then it means it combined with the same antigen. Depending no the solutions that clotted it showed the blood type of the person. *See the chart in the forensic report at the bottom for a more detailed compilation of the data and research.
Pedigree and Family Connections: In the crime report, we received background information on all of the suspects and the victim. Family information was provided and we constructed a pedigree for each suspect that links relationships, gender, genetic diseases, and blood type throughout generations. This made it easier to track the suspects information and possible motives caused by previous accidents or situations. The victim was related to many of the suspects and ruined several families because of his choices; this may have resulted in his preplanned death. It turns out that most of the suspects were interconnected. *See the chart in the forensic report at the bottom for a more detailed compilation of the data and research.
Reflection: Throughout this project, I learned many things concerning both the genetic research and the legal formatting of a court case. In order to gather evidence, our group needed to perform several experiments using genetics. I especially enjoyed these two aspects because I could apply them to myself and look at my own fingerprint of blood type. Overall we learned about DNA sequences, blooding clotting, pedigrees, fingerprinting, chromotography, different types of genetic diseases, and karyotypes(See other sections for more information[not yet though- when I finish this website update this note will be deleted]). In the science aspect, I would want to learn more about how karyotypes are actually made(not just cutting out and gluing pieces of paper) and I would want to learn more about the DNA sequences that we ran through the gels. I also grasped concepts concerning the legal applications that take place in a court room; this includes researching the different levels of murder and I learned that an excessive amount of evidence is needed in order to just obtain an arrest warrant. In this field, I would want to learn more about how an actual court process would be like. I would like to try presenting with a cross-examination and responding to more questions from the jury, judge, or defendant.
Next year, I think this project would run better if the experiments seemed more realistic. Many times, it felt like some experiments such as the karyotyping was an art project at elementary school level. I also think this project could be improved next year by providing more diverse evidence with a more structured crime story. During this investigation, there were many holes between the crime scene photos, background information, crime report, and actual evidence.
I believe that my group was very time efficient and was constantly working studiously on this project. This hard work was displayed in our presentation because each member was aware of their speaking parts, proper attire, and explanation of ideas. Each group member was able to contribute to all the aspects of this project including the experiments, PowerPoint, posters, and crime report script. Personally, I stayed on task throughout the project during both the evidence gathering and construction of our presentation. I think I presented well because I learned the material ahead of time and didn't need to rely on the prewritten outline of our script. If I were to do this project again, I would probably want to present second so our group was not as rushed in the morning and we could review the PowerPoint; however, the actual preparation for the presentation was faultless. An In-vest--igator.
Next year, I think this project would run better if the experiments seemed more realistic. Many times, it felt like some experiments such as the karyotyping was an art project at elementary school level. I also think this project could be improved next year by providing more diverse evidence with a more structured crime story. During this investigation, there were many holes between the crime scene photos, background information, crime report, and actual evidence.
I believe that my group was very time efficient and was constantly working studiously on this project. This hard work was displayed in our presentation because each member was aware of their speaking parts, proper attire, and explanation of ideas. Each group member was able to contribute to all the aspects of this project including the experiments, PowerPoint, posters, and crime report script. Personally, I stayed on task throughout the project during both the evidence gathering and construction of our presentation. I think I presented well because I learned the material ahead of time and didn't need to rely on the prewritten outline of our script. If I were to do this project again, I would probably want to present second so our group was not as rushed in the morning and we could review the PowerPoint; however, the actual preparation for the presentation was faultless. An In-vest--igator.
Recorded Data and Background Information
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PowerPoint Presentation
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