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Forensic science chapter 3 review hair
Forensic science chapter 3 review hair
Forensic science chapter 3 review hair
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Hello, I am Anthony Estevez. I perform forensic hair analysis for the Crime Scene Investigation Unit in New York City. I am here to provide evidence against the defendant, based upon microscopic hair analysis. Here, you can see a close-up view of a hair shaft. First, there is the cuticle. The cuticle is the outermost layer of the hair shaft. It is colorless, and it provides protection to the cortex and other internal structures of the hair. The cortex is the middle layer of the hair shaft, and it provides the color, texture, and strength of hair. The medulla is the innermost layer of the hair shaft. There are 4 different types of medulla, and they all play a part in the coloration of the hair. When analyzing hair macroscopically, you can distinguish many characteristics, such as color, racial difference, texture, damage, and curl pattern. When analyzing hair microscopically, you can find distinguish both the previous characteristics, but you can also analyze the patterns of the medulla, and the impurities that the hair absorbs through exposure to drugs and other substances. …show more content…
Hair is considered class evidence, meaning that it is not specific to one person, but pertains to a group of people. This may seem like bad evidence; however, it is very useful in narrowing down suspects. Because people tend to drop hair wherever they go, it is very easy to find hair evidence. With a strand of hair, we can determine the race, hair color, if the hair has been dyed, and the types of medulla the suspect can have. If the hair was forcefully removed, it can provide the blood type and even the Nuclear DNA of the suspect if the hair bulb was
Just because a hair is found at the scene doesn’t mean that it belongs to the perpetrator. It is important to take Locard’s Principle into account, “The microscopic debris that cover our bodies are the mute witnesses... of all our movements and all our encounters.” (Robertson, 7.2) When you come into contact with something or someone, there is always a transfer, even if it isn’t noticeable. There are different types of transferring, primary and secondary. Primary transfer is when something transfers from you to another source. When someone comes into contact with that source, there is a chance that your hair or fiber transfers onto the other person. This is secondary transfer. Because humans shed hair frequently, it is easy for hair to go through secondary transfer and end up somewhere that the individual had never been. Hair can remain on a source for a couple hours without being transferred and it does not break down very easily, so this can remain in place for a long time. (Robertson,
The hair of the scalp is longer and more flexible, while the hair of the eyebrows tends to be short and stiff. Oval shaped hair shafts produce wavy hair, flat hair shafts create curly hair and hair shafts that are perfectly round create straight hair. There are also different types of melanin, a natural compound responsible for the production of color in the eyes, skin and hair. There is yellow, brown and black melanin, each produced by melanocytes located at the follicle base. With age, melanin production decreases, causing greying of hair. (Applegate & Saunders, 2001, pp
. DNA can be left or collected from the hair, saliva, blood, mucus, semen, urine, fecal matter, and even the bones. DNA analysis has been the most recent technique employed by the forensic science community to identify a suspect or victim since the use of fingerprinting. Moreover, since the introduction of this new technique, there has been a large number of individuals released or convicted of crimes based on DNA left at the crime scene. DNA is the abbreviation for deoxyribonucleic acid.
The blood of the unknown person became apparent through comparing the blood type found at the crime scene with the contrasting blood types of the suspects. The blood identified at the crime scene could have possibly belonged to Anna Garcia or Erica Piedmont. This observation was based on the information that the blood type found at the crime scene was type A and these two individuals are the only ones that carry that specific type. In similarity, a microscopic photography was taken of the unknown hair follicle found at the crime scene. Then hair samples were taken from the potential suspects, and the victim. These findings were then compared. This was done by looking at each individuals hair follicles and comparing it with the unknown one. By looking at the similarities and differences in medulla diameter, the discovery of the unknown hair follicle became established that it belonged to Anna Garcia. Further examination resulted in the analyzation of a shoe print found at the crime scene. Shoe patterns and sizes were taken from each suspect, including the victims. They were then identified and compared to the one found at the crime scene. By looking at the distinct pattern, size, and the fact that both shoes were a Columbia brand sneaker it became obvious that the shoe print was extremely similar to Anna’s shoe design. Through this found evidence it became
These hairs may be of evidentiary value to show contact between two people. With an adequate hair standard, a trace chemist will be able to microscopically compare an unknown hair to a standard collection and determine if the unknown hair could have come from the individual under investigation. Hair comparisons can not identify hair as coming from one individual to the exclusion of anyone else. DNA testing can strengthen any possible association with the hairs." - Locard.... ... middle of paper ... ...
piece of hair, a spot of blood, or skin tissue and make a positive identification on a
The most important type of evidence is DNA. When DNA testing takes place, the samples are collected from the suspect and the crime scene. These evidences include hair, fingerprint, human secretions, blood, semen and other bodily fluids, are collected and sent to the lab for further investigation.
The criminal justice system has changed a lot since the good old days of the Wild West when pretty much anything was legal. Criminals were dealt with in any fashion the law enforcement saw fit. The science of catching criminals has evolved since these days. We are better at catching criminals than ever and we owe this advancement to forensic science. The development of forensic science has given us the important techniques of fingerprinting and DNA analysis. We can use these techniques to catch criminals, prove people's innocence, and keep track of inmates after they have been paroled. There are many different ways of solving crimes using forensic evidence. One of these ways is using blood spatter analysis; this is where the distribution and pattern of bloodstains is studied to find the nature of the event that caused the blood spatter. Many things go into the determination of the cause including: the effects of various types of physical forces on blood, the interaction between blood and the surfaces on which it falls, the location of the person shedding the blood, the location and actions of the assailant, and the movement of them both during the incident. Another common type of forensic evidence is trace evidence. This is commonly recovered from any number of items at a crime scene. These items can include carpet fibers, clothing fibers, or hair found in or around the crime scene. Hairs recovered from crime scenes can be used as an important source of DNA. Examination of material recovered from a victim's or suspect's clothing can allow association to be made between the victim and other people, places, or things involved in the investigation. DNA analysis is the most important part of forensic science. DNA evidence can come in many forms at the crime scene. Some of these forms include hair; bodily fluids recovered at the crime scene or on the victim's body, skin under the victim's fingernails, blood, and many others. This DNA can be the basis of someone's guilt or innocence; it has decided many cases in the twentieth century. As the times continue to change and the criminals get smarter we will always need to find new ways to catch them. Forensic science is the most advanced method yet, but is only the beginning. As the field of science grows so will the abilities of the
Once a crime has been committed the most important item to recover is any type of evidence left at the scene. If the suspect left any Deoxyribonucleic acid (DNA) at the crime scene, he could then be linked to the crime and eventually charged. A suspect’s DNA can be recovered if the suspect leaves a sample of his or her DNA at the crime scene. However, this method was not always used to track down a suspect. Not too long ago, detectives used to use bite marks, blood stain detection, blood grouping as the primary tool to identify a suspect. DNA can be left or collected from the hair, saliva, blood, mucus, semen, urine, fecal matter, and even the bones. DNA analysis has been the most recent technique employed by the forensic science community to identify a suspect or victim since the use of fingerprinting. Moreover, since the introduction of this new technique it has been a la...
Whereas the real picture of forensic evidence is unlike what is represented in movies and television shows where a fingerprint or a trace of hair is found, then it’s game over for the criminal. Reality is not as straightforward. As more people are exposed to the unreal forensic world through television and media the likeliness for a wrong conviction increases with juries assuming the evidence involves more science than what it really does, this is known as the CSI Effect. Further education and training is needed for the people of the court, the forensic specialists, and so called experts. The people in courts do not question any of the ‘professionals’ and just trust in their expertise. The court could overcome this perception by requiring explanation of error rates in a forensic field. To do this, testing examiner error rates will be necessary which means further research. Forensic science has such a large effect on the prosecution of suspects, experts have been known to provide questionable and at times incorrect evidence. When a false conviction occurs the true perpetrator is set free. Once realized, the public doubts the justice system and the reliability of the forensic evidence even more. At this point in time, forensic is an inexact
Throughout the semester we have studied the black vernacular tradition and its attributes of competition, group interaction, the in- group, and pattern of call and response and we have learned to take those attributes and apply then to the complex subject of Black Hair. Black Hair is a complex subject not only because so little is known about it but because of the aesthetic, political, and interpersonal context through which Black hair can be studied and interpreted. Hair is honestly in just about every text and it is used to not only add insight to characters identity but to also give context to time. Many of the black vernacular tenets are seen throughout Margo Jefferson’s chapter in Negroland, in particular the first section called “The
It has often been said that hair weaves are typically thought to be used by African Americans. Weaving is a technique that consist of sewing artificial or human hair that has been sewn onto a weft onto braids or a weaving net. A weaving net helps to protect your hair from damage caused by the tension of the thread while pulling it to secure the wefts.
Forensic Science, recognized as Forensics, is the solicitation of science to law to understand evidences for crime investigation. Forensic scientists are investigators that collect evidences at the crime scene and analyse it uses technology to reveal scientific evidence in a range of fields. Physical evidence are included things that can be seen, whether with the naked eye or through the use of magnification or other analytical tools. Some of this evidence is categorized as impression evidence2.In this report I’ll determine the areas of forensic science that are relevant to particular investigation and setting out in what method the forensic science procedures I have recognized that would be useful for the particular crime scene.
Hair is an important part of our body. It can be found anywhere and can be a useful evidence in forensic science. It consists of three layers, namely cuticle, cortex and medulla. Cuticle- is a covering that consists of hard scales made of keratin, which is a protein approaching tip ends of the hair. There are three types of cuticle: coronal, imbricated and spinous types. Cortex consists of stretched out beam shaped cells, buried with pigment granules for hair to cede with color and is the main body of the hair shaft. It may also contain pigment granula, ovoid bodies and cortical fusi (Wright, 2008). Furthermore, medulla can be categorized into continuous, fragmental, absent and interrupted types. If medulla
They have several different factors that determine hair color such as melanin containing iron and sulfur. If there is a lack of melanin, the hair will be white or gray. Stem cells located in the dermis are responsible for the production of hair. The shape and texture of the hair follicle determine an individual’s hair. The growth process of hair goes through the following three phases. The anagen phase which takes approximately twenty eight days and grows about one centimeter. The catagen phase lasts for approximately two to three weeks and the blood supply to the hair is cut off. The telogen phase is the final phase also known as the resting phase, lasting approximately three