In this project we were tasked of solving the murder of one Carleton Comet, through means of forensic science and our prior knowledge. We used skills including DNA fingerprinting, dusting for fingerprints, ink chromatography, and reading pedigrees (all of which will be discussed further in the content section). This project was part of our genetics unit and we used a lot of our knowledge and vocabulary from genetics to help us understand the case materials and solve the case. The evidence that we found/were provided was the crime report, family histories, the knife that was used to kill Carelton Comet, a death note, and three pens. In the beginning of our project we were given a crime report of what occured/what the situation was. The goal of this project was for us to ue the information to determine the Carelton Comet killer and their motive. Here was the crime report we were given:
Crime Report
The wind blew and the fog began to roll in on the night of February 14, 2019. A picnic was being held on Chalk Hill at the edge of the San Marin High School campus in honor of an eccentric former student, Carelton Comet and to celebrate Valentine's Day.
Carelton Comet, a mysterious person, was just released from prison and possesses a new name. He decided to have a celebration party with people he considered old friends or acquaintances.
7:00 p.m.:
Carelton Comet escorted Nancy Normal, Theresa Terra, Fred Flimmer, Sam Sophomore and Glen Glee to the picnic site. Although the guests didn’t know it, each of their lives had somehow been affected by Carelton Comet.
7:30 p.m.:
The host and guests sat down to a dinner of tomato soup, fresh garden salad, prime rib, baked potato and small talk.
7:35 p.m.:
The sky suddenly darkened. The picnic blanket rustled, a glass was dropped, people screamed and Carelton Comet groaned loudly.
7:36 p.m.:
The sun returned to show Carelton Comet slumped forward, his face in his bowl and a large steak knife in the back of his neck.
7:40 p.m.:
The police are called.
7:55 p.m.:
The police arrive.
8:00 p.m.:
Carelton Comet is officially pronounced dead at the scene. The knife is bagged and quickly sent to the crime lab. Police interview the guests. Someone attends to Nancy Normal who cut her hand on a bit of broken glass when the sky darkened.
9:30 p.m.:
The police lab determined that there were two types of blood on the knife. One belonged to Carelton Comet
The lab reports are enclosed along with important information about all of the Captain’s dinner guests.
The wind blew and the fog began to roll in on the night of February 14, 2019. A picnic was being held on Chalk Hill at the edge of the San Marin High School campus in honor of an eccentric former student, Carelton Comet and to celebrate Valentine's Day.
Carelton Comet, a mysterious person, was just released from prison and possesses a new name. He decided to have a celebration party with people he considered old friends or acquaintances.
7:00 p.m.:
Carelton Comet escorted Nancy Normal, Theresa Terra, Fred Flimmer, Sam Sophomore and Glen Glee to the picnic site. Although the guests didn’t know it, each of their lives had somehow been affected by Carelton Comet.
7:30 p.m.:
The host and guests sat down to a dinner of tomato soup, fresh garden salad, prime rib, baked potato and small talk.
7:35 p.m.:
The sky suddenly darkened. The picnic blanket rustled, a glass was dropped, people screamed and Carelton Comet groaned loudly.
7:36 p.m.:
The sun returned to show Carelton Comet slumped forward, his face in his bowl and a large steak knife in the back of his neck.
7:40 p.m.:
The police are called.
7:55 p.m.:
The police arrive.
8:00 p.m.:
Carelton Comet is officially pronounced dead at the scene. The knife is bagged and quickly sent to the crime lab. Police interview the guests. Someone attends to Nancy Normal who cut her hand on a bit of broken glass when the sky darkened.
9:30 p.m.:
The police lab determined that there were two types of blood on the knife. One belonged to Carelton Comet
The lab reports are enclosed along with important information about all of the Captain’s dinner guests.
My group and I came to the conclusion that Nancy Normal was the murderer, and Sam Sophomore was an accomplice and had something to do with the murder of Mr. Comet. We created a slideshow presentation of all of our evidence and how it pointed to these two culprits. We presented this slideshow in front of three upper-class judges who are part of San Marin's mock trial team, and asked them for arrest warrants for both Nancy and Sam. In the end, we were given the arrest warrant for Nancy Normal for first degree murder, but we were denied the warrant for Sam Sophomore due to lack of evidence. Below is the slideshow presentation that we created and presented to our class and the judges.
Techniques Used In Our Investigation
Above is an accurate image of the fingerprint that my group and I dusted for; that was found near the body. It matched with the suspect Nancy Normal
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One of the forensic science methods that we used to come to our conclusion, and compile evidence was fingerprinting. Fingerprinting is when there is a set or singular fingerprint found on a surface at a crime scene or piece of evidence, and it is dusted with loose powder to reveal the print(s). The print is then lifted onto a piece of tape or evidence holder of some kind for preservation. There was a fingerprint found near the body on a glass table, and we were tasked to find out who the print most likely belonged to. We were given photos of all the suspect's fingerprints and compared on a glass table, and we were |
tasked to find out who the print most likely belonged to. We were given photos of all the suspect's fingerprints and compared the fingerprint that we dusted for with the photos given to us. We studied the different characteristics of fingerprints and the different patterns they can be including whorls, archs, and loops. We came to the conclusion that the fingerprint most likely belonged to Nancy Normal.
Another forensic science method that we used in this investigation was Ink chromatography. Chromatography is the physical separation of a mixture into its individual components, specifically ink in this case. When ink is exposed to certain solvents the colors dissolve and can be separated out. When we expose a piece of paper with ink on it to a solvent, the ink spreads across the paper when the ink dissolves. It can lead to to a specific pen in this case, because of the specific ink that the pen would have is being
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An image of the note that was found with Mr. Comet's body
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tested. There was a note found at the crime scene and with this method, since different ink pens hold different ink types, we could tell what pen was used to write the note. The note read " you are a dead man" in black ink. We tested three different pens that were found on the suspects, and found that pen #2 was the one used to write the threatening note. This pen was also owned by Nancy Normal and Sam Sophomore, which means that one of them had to have written the note.
Another piece of information that assisted us in convicting Nancy Normal with first degree murder was family histories and pedigrees. Pedigrees are a diagram that shows the occurrence and appearance or phenotypes of a particular gene or organism and its ancestors from one generation to the next. From the information given to us of family histories of the victim and suspects, my group and I created a pedigree for each person in the case. To our surprise, all of the people involved with the crime seemed to have been related and were affected by a man named Thomas Sandstone. With further investigating, we came to the conclusion that Carelton Comet is actually Thomas Sandstone. Both claim to have had many affairs with different women, multiple illegitimate children, and an unclear past and mystery to them. |
Here is a key and simple example of a pedigree and it's symbols for better understanding and organization
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The pedigrees and family history established a clear motive for Nancy Normal, which was her uncontrollable love for Fred Flimmer. Thomas Sandstone (Carleton Comet) was Fred's father and he killed Fred's mother and sister in a complicated love triangle. Nancy would have wanted to kill Carelton Comet out of love, and thought maybe she could get Fred's attention or impress him through the murder. As for Sam Sophomore, Thomas Sandstone (Carelton Comet) murdered Peebles Sandstone who was Fred's sister and Sam's fiance. He would have wanted revenge for the murder of his fiance and to avenge Peebles' untimely death. From the pedigrees we were also able to uncover some information on family diseases that had been passed down to the suspects. It turns out that Nancy and Sam had Huntington's Disease which affects the brain and causes compulsive behavior, fidgeting, irritability, or lack of restraint, mental confusion, and delusion. This would make Nancy and Sam at risk to commit a crime such as murder, and make it seem valid or reasonable in their minds. Although they both had this disease that coulded their judgment, there was still premeditation with the note found at the scene which shows rational thinking so the actions cannot be dismissed for this mental disability.
Another way that we used forensic science in this case was examining blood types. Blood type is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells. The blood types that we looked at for this case included type A,B,O, and AB. Here on the right is the chart that we complied with the suspects and their matching blood type. We found the suspect's blood types through testing and in the lab.
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Evidence wise, and why this is relevant, is because at the crime scene there were two different blood types found on the murder weapon. There was type O and type A. Logically the type O must belong to Carelton Comet, since he was the one who was murdered and had the knife in his neck. Whereas Nancy Normal has type A blood, and the blood on the knife was also type A which ties he to the murder weapon. While there are also other people with type A blood, I will show you why the blood on the knife must be hers in the next technique that we used.
We then looked further into whose blood was really on the knife through examining karyotypes. Karyotype is the number and visual appearance of the chromosomes in an organism's cell. Chromosomes are threadlike structures that are made of nucleic acid and they carry/protect genetic information. Examining the karyotypes allowed us to determine of the suspects had any sort of chromosomal disease, which is a disease caused by chromosomes that are partially or completely missing, altered, or duplicated. We found that Carelton Comet had Jacob's Syndrome, which is only found in males and can lead to learning disabilities, and was the only person to have this chromosomal disorder. One of the blood samples found on the knife showed to have Jacob's Syndrome; so we know that one of the blood samples was Carelton's. Nancy Normal also had a chromosomal disease which is called Triple X Syndrome, it is a random mutation found in women that can affect the brain. She is the only person to have Triple X Syndrome out of the suspects, and the second blood sample from the knife showed that the person had Triple X Syndrome; in short Nancy also had her blood on the knife.
An image of the DNA fingerprinting after completion
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We also used a technique called DNA fingerprinting which is when you look at and compare DNA. It shows individual's DNA traits, matches unknown DNA to a suspect, and can be used to identify diseases and relatives. This helped in our case, because we were able to match an unknown piece of DNA to one of our suspects. Crime scene number one ended up matching with Carelton Comet's DNA (the colors matched), while crime scene number two matched with none other than Nancy Normal. In other words, her blood was found on the knife along with her DNA.
It's not surprising that Mr. Comet's blood and DNA were on the knife seeing as he was the one killed with it. |
In conclusion, we were able to charge Nancy Normal with an arrest warrant for first degree murder with this evidence:
For Sam Sophomore we complied the evidence as best we could for him to get an arrest warrant, but there just wasn't enough. While we did not get the arrest warrant for him at the moment, we are still going to look into his involvement with the murder further. Here is the evidence that we found against Sam:
- She was one of the owners of the pen that was used to write the threatening note
- Writing the note shows that this was a premeditated murder
- Her blood type was found on the knife that was used to kill Carleton and Karyotypes match
- Likely there because she cut herself while stabbing Mr. Comet
- Shows she would have been the one to physically murder him
- She was in love with Fred Flimmer, whose father was Thomas Sandstone (Carleton Comet)
- He killed two people in a wild love triangle
- Nancy figured it out and killed Carleton in a way to get Fred’s attention or impress him
- Had Huntington’s disease (mentally unstable)
- Match for DNA fingerprinting
For Sam Sophomore we complied the evidence as best we could for him to get an arrest warrant, but there just wasn't enough. While we did not get the arrest warrant for him at the moment, we are still going to look into his involvement with the murder further. Here is the evidence that we found against Sam:
- One of the owners of the pen that was used to write the threatening note
- Had Huntington’s disease, was also mentally unstable and at risk to commit something like murder
- Sam was engaged to Peebles Sandstone
- Who was murdered by Thomas Sandstone (Carleton Comet)
- Wants to kill him out of vengeance for killing his fiancé
- Also has been seen with Nancy Normal recently
- Conspiring?
- Since Nancy’s blood was on the knife she physically murdered Carleton
- Sam assisted or helped her carry it out
To Better Understand
The following is some helpful genetics vocabulary that we learned during this project that was useful in understanding how to interpret or describe the evidence we found.
The following is some helpful genetics vocabulary that we learned during this project that was useful in understanding how to interpret or describe the evidence we found.
Heterozygous- when genotype is different alleles
Dominant- trait will always be expressed if present Recessive- trait needs to be homozygous to be expressed Codominant- one trait is not dominant over the other so the phenotype is both (ex AB blood) Incomplete Dominance- when neither trait is dominant so phenotype is a mixture of both (ex pink flowers) Inheritance- traits that are passed down from parents to offspring Variation- differences within the same trait Haploid- a cell that has one set of genetic material |
Gene- DNA code for a specific trait
Allele- variation of a gene (genetic code) Chromosome- all genetic information stored in a safe way Phenotype- how traits are expressed physically Genotype- genetic makeup/alleles Central Dogma- protein synthesis (DNA to mRNA to Protein) Homologous- when genotype is same alleles Diploid- a cell that has two sets of the same genetic material Punnett Square- diagram showing possible offspring genetic genotype and phenotype |
DNA Replication- the process of producing two identical replicas of DNA from one original DNA molecule. This process occurs in all living organisms and is vital for life and maintaining functions.
DNA Mutations- an irreversible change in a living organism's DNA that can affect it physically or genetically, and mutations allow for genetic variation (differences within the same trait or gene). Mutations can lead to diseases such as Huntington's disease, which was a disease that both Nancy Normal and Sam Sophomore had in this case.
DNA Mutations- an irreversible change in a living organism's DNA that can affect it physically or genetically, and mutations allow for genetic variation (differences within the same trait or gene). Mutations can lead to diseases such as Huntington's disease, which was a disease that both Nancy Normal and Sam Sophomore had in this case.
DNA Structure- DNA is composed of a molecules known as nucleotides, has a sugar phosphate backbone, nitrogen base, and is in a double helix form. The nitrogen base pairs are adenine (A), thymine (T), guanine (G) and cytosine (C). These base pairs and their order determine the DNA's function and instructions. The image to the left is an example of a DNA's structure and what it looks like.
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All of these terms were important to our project and applied to it, because they related to genetics which was the focal point of all our science in this unit. With this vocabulary we were able to describe and analyze information that we found about the case to construct our presentation or synthesise a conclusion as to who was capable of the murder.
Reflection
Two skills that I performed well in this project was leadership and organization. The first skill that I utilized well was leadership. A specific example of when this skill was showcased, was toward the end of our project. My group and I were working on our presentation for the judges, when I realized that I was the only one working on the doc and everyone else was distracted. I told them that I needed their help, and to get back to work so we could finish and get a good grade on the project. The listened to me, got back on their chromebooks and asked me what I wanted/needed them to do to get the project done. This showed me that they saw me as the leader and the person that they are supposed to be listening or taking directions from, and it helped us stay on target. The second skill that I utilized well was organization. A specific example of when I used this skill well was the first day of the project. We were given a lot of documents and a folder to keep all of our information in and our conclusive packet in. I made sure that everything was in the right place, and continuously kept our packet up to date by adding all the necessary information to it when we collected new evidence. This helped us out in the long run, because we were able to easily look back at all of our data collected and knew where everything was for when we needed it.
Two skills that I still need to work on for future projects is communication and time management. The first skill that I still need to work on is communication. This proved to be an issue specifically when we it came time to present our information to the judges. I had added some new slide and points to bring up to strengthen our argument, so I mentioned it to my group and asked them to look over the edited slides. When we presented it was clear that some of my teammates had not read or been prepared for the changes/edits, and that was probably because there was not enough communication between us to finalize our thoughts. In the future I will make sure that my groups are clear on what we need to look over at home so our arguments and presentations will be more strong and cohesive. The second skill that I still need to work on is time management. A specific example of when this proved to be an issue was the last work day we had on this project. My group and I were working on the presentation, and we were close to the end of the period when I realized that we were not going to be ready to present the next day. We had been so worried about finishing the slideshow that we ad not finished our notecards or even practiced yet. In the future I will be sure that we carve more time out to get everything done in a timely manner, so this kind of situation won't happen again where we are presenting but not really prepared to do so.
All in all, this project was my favorite so far this year! I was very interested in seeing how science is used in real life for something as serious, yet fascinating, as a murder. I was able to experience a kind of profession that I had always wondered about doing in the future, and I was not disappointed. I really hope that we are able to experience more science based profession in more projects in the future!
Two skills that I performed well in this project was leadership and organization. The first skill that I utilized well was leadership. A specific example of when this skill was showcased, was toward the end of our project. My group and I were working on our presentation for the judges, when I realized that I was the only one working on the doc and everyone else was distracted. I told them that I needed their help, and to get back to work so we could finish and get a good grade on the project. The listened to me, got back on their chromebooks and asked me what I wanted/needed them to do to get the project done. This showed me that they saw me as the leader and the person that they are supposed to be listening or taking directions from, and it helped us stay on target. The second skill that I utilized well was organization. A specific example of when I used this skill well was the first day of the project. We were given a lot of documents and a folder to keep all of our information in and our conclusive packet in. I made sure that everything was in the right place, and continuously kept our packet up to date by adding all the necessary information to it when we collected new evidence. This helped us out in the long run, because we were able to easily look back at all of our data collected and knew where everything was for when we needed it.
Two skills that I still need to work on for future projects is communication and time management. The first skill that I still need to work on is communication. This proved to be an issue specifically when we it came time to present our information to the judges. I had added some new slide and points to bring up to strengthen our argument, so I mentioned it to my group and asked them to look over the edited slides. When we presented it was clear that some of my teammates had not read or been prepared for the changes/edits, and that was probably because there was not enough communication between us to finalize our thoughts. In the future I will make sure that my groups are clear on what we need to look over at home so our arguments and presentations will be more strong and cohesive. The second skill that I still need to work on is time management. A specific example of when this proved to be an issue was the last work day we had on this project. My group and I were working on the presentation, and we were close to the end of the period when I realized that we were not going to be ready to present the next day. We had been so worried about finishing the slideshow that we ad not finished our notecards or even practiced yet. In the future I will be sure that we carve more time out to get everything done in a timely manner, so this kind of situation won't happen again where we are presenting but not really prepared to do so.
All in all, this project was my favorite so far this year! I was very interested in seeing how science is used in real life for something as serious, yet fascinating, as a murder. I was able to experience a kind of profession that I had always wondered about doing in the future, and I was not disappointed. I really hope that we are able to experience more science based profession in more projects in the future!