Trace Evidence Essay, Research Paper
Trace evidence is very important in forensic investigations. This category of evidence encompasses many
diverse types of microscopic materials as well as some examples that are easily visible to the naked eye.
The subject is broad and diverse because of the number of different types of evidence that are commonly
encountered. Trace evidence can be thought of as evidence occuring in sizes so small that it can be
transferred or exchanged between two surfaces without being noticed. Varieties of trace evidence can
include, but are not limited to: metal filings, glass fragments, feathers, food stains, building materials,
lubricants, fingernail scrapings, pollens and spores, cosmetics, plastic fragments, gunshot residue,
chemicals, paper fibers and sawdust, human and animal hairs, plant and vegetable fibers, blood and other
body fluids, asphalt or tar, vegetable fats and oils, dusts and other airborne particles, insulation, textile
fibers, soot, soils and mineral grains, and e!
xplosive residues.
Forensic scientists routinely come into contact with a relatively few number of these. They are: hair, glass,
paint, fibers, fingerprints, and flamable liquids. These will be covered more in-depth in this paper.
Edmond Locard, a French scientist and one of the early pioneers in forensic science believed strongly that
individuals could not enter an area without taking dust particles with them from the scene. This became
known as what is now called “Locard’s Exchange Principle.” This principle states that when two objects
come into contact with each other, each of the objects will leave particles of one on the other. It is this
principle that is the foundation of the forensic study of trace evidence.
Trace evidence examination is the examination and analysis of small particles in order to help establish a
link between a suspect and a crime scene or a suspect and the victim of a crime. These small particles
usually include such items as hair, paint, glass, and fibers. Although not considered “trace” items by
definition the many Crime Labs also examine and analyze such important evidence as flammables (in arson
investigations), fingerprints, footwear (shoeprints), and “fracture matches.” Many also perform
examinations of automobile headlamps, taillights and speedometers.
The first category of trace evidence I will discuss is hair. Hair is examined grossly (with the naked eye),
and with both low power and high power microscopes to determine if questioned hairs, found at the scene
or on the clothing of an individual are consistent in characteristics to known hair collected from the suspect
and/or victim. Some of these characteristics include more obvious traits such as color, length, and
morphological shape and also microscopic aspects of the cuticle, cortex and medulla, which are the three
basic components of a hair. A hair cannot be linked specifically to an individual through these methods but
vital information developed as to who the suspect may be and significant elimination of other suspects can
often be done. It is possible to tell the race, sex, and region of the body that a hair comes from. A relative
idea as to the time since the last haircut can also be made.
The second type of trace evidence is glass. When larger samples are available glass can be useful in linking
a suspect with the crime scene through “fracture matches”. This is when a larger piece of glass, found
associated with the suspect, can be physically fitted with one or more pieces from the crime scene. More
often when an individual gains access to a business or dwelling by breaking glass the perpetrator will
acquire very tiny pieces of glass on his/her clothing. These cannot be physically matched due to their tiny
size. However, these pieces, though smaller than a pinhead, can be characterized under the microscope.
After proper gross and low power microscopic examinations are performed the Forensic Scientists use
microscopic “refractive index” determination to further characterize the samples. Refractive index is a
measurement of how light is “refracted” (bent) as it passes through the microscopic glass sample. Glasses
having different formulations and used for differe!
nt purposes have different RI’s. Therefore samples can be compared to determine if the glass from the
crime scene could be the source of the glass removed from the suspect’s clothes.
The third type of trace evidence is paint. When perpetrators break into businesses or dwellings they have
the potential of acquiring small paint samples during their illegal visit. And usually when cars and/or trucks
collide there is a significant chance that paint from either vehicle will transfer to the other. Many Forensic
Scientists will perform tests on these samples even though they may be pinhead in size. These initial tests
include low power magnification (macroscopic) to determine color, paint layer sequence, thickness, and
overall texture. If the questioned and known paint samples appear the same they then perform analytical
chemical examinations including solubility test, and analytical instrumental examinations. These later tests
give further characterization to the paints in order to determine if they could share a common origin.
The next kind of trace evidence is fibers. Fiber examination usually concerns itself with the potential
transfer of clothing fibers between individuals who have come into contact with each other or fiber
transfers between a suspect and carpet and/or other environmental fiber donors at a crime scene.
Questioned and known fibers are examined and compared using microscopic and analytical instrumental
techniques much like paint is analyzed. As with most trace evidence, individual fibers cannot be said to
come from a particular item of clothing or fabric. However, finding fibers with the same generic
composition (e.g. polyester), color, shade, and morphology(shape) on the suspect with known fibers from
the scene can be of significant value in both investigation and prosecution of a criminal case. Fiber analysis
has often demonstrated that the body of an individual was likely transported in the trunk of an automobile.
Flammable liqiuds are also a type of trace evidence. When arson investigators are called to the scene of a
fire one of their foremost methods to determine that a suspicious fire was deliberately started is by taking
samples from the burned scene and submitting them to Arson examinations. Burned debris samples are
taken by the investigator in airtight cans. The labs then perform careful extractions on the contents of the
cans. These extracts are analyzed using sophisticated and very sensitive instrumental techniques. In some
cases, petroleum residues less than one microliter (0.00004 ounces) can be found in the debris from the
scene. Since most of these are not naturally ocurring in nature the prosecutors can argue that it was put
there.
The last type of trace evidence covered in this paper is fingerprint evidence. Some Forensic Scientists
perform examinations on various items submitted to them, as well as processing crime scenes, to determine
if usable fingerprints are present. The labs use classical fingerprint processes such as dusting powders,
ninhydrin solutions and “Superglue” techniques. They also use the latest advances in detection technology
such as laser lighting and computer enhanced imaging. These later techniques are valuable in examining
very faint latent prints, smeared/smudged prints, and prints on multicolored surfaces. They are also
extremely useful in the examination of blurred surveillance photos and other photos that may be otherwise
deemed useless.
Trace evidence is a very important part of forensic science and plays a large role in identifying perpetrators
of crime. One of the best values of trace evidence is that its deposition is almost always unnoticed. Its
importance can not be minimized however, as the article clearly shows. Many different scientific
techniques are utilized to analyze trace evidence as hopefully, I’ve shown.
Другие работы по теме:
The Tradition Challenged
– Alfred Dreyfus And Emile Zola Essay, Research Paper Captain Alfred Dreyfus was arrested in 1894 for treason. He was charged with giving military secrets to Germany. However his conviction was based on circumstantial evidence. Dreyfus was framed. While he suffered on Devils Island new evidence came about that indicated his innocence and nothing was done about it.
Cognition Essay Research Paper 10 What are
Cognition Essay, Research Paper 10) What are some other key biases that influence judgement? Judgement seems to be influenced by a variety of things each have their own implication on judgement. Overconfidence serves as a bias on judgement. Fischhoff, Slovic, and Lichtenstein, in 1997, tested this idea.
Defense On Behalf Of Palamedes Essay Research
Paper In “Defense on Behalf of Palamedes”, Gorgias attempts to prove Palamedes is innocent by making his defense in every possible way. He does this by using evidence about Palamedes, evidence that has direct relation to the
Mad City Essay Research Paper The movie
Mad City Essay, Research Paper The movie Mad City demonstrates to us how the media can control our lives. The media is willing to go to any length for the money a story can bring. Max portrays the role of humanity in this film. Max represents the humanity of the media. He seems to be the only trace of humanity in all of the media.
Innocently Executed Essay Research Paper Innicent men
Innocently Executed Essay, Research Paper Innicent men have been executed in the United States. According to a report published by the National Coalition to Abolish the Death Penalty, or the NCADP, 23 innocent men have been executed in the U.S. this century. About 4.5 people are wrongly convicted of capital crimes each year.
Eyewitness Testimony Essay Research Paper Eyewitness TestimonyEyewitness
Eyewitness Testimony Essay, Research Paper Eyewitness Testimony Eyewitness testimony is a controversial issue that separates people into two groups, those that support eyewitness testimony and those that do not. When an eyewitness identifies an individual as the person who committed the crime, the evidence can be very convincing.
Washburn V State Essay Research Paper The
Washburn V. State Essay, Research Paper The evidence presented to myself and the other juror?s proves that Tyrone Washburn is guilty beyond a reasonable doubt of the murder of his wife, Elena Washburn. On March 12, 1979 Elena Washburn was strangled in the living room of her family?s home. Her body was then dragged to the garage, leaving a trail of blood from the living room to the place it was found.
Archaeologists Essay Research Paper Archaeologists must question
Archaeologists Essay, Research Paper Archaeologists must question their sources in order to gain appropriate knowledge from them. Some questions archaeologist may ask include; What is it? What is it made from? What size is it? Where did it come from? When was it made and by whom? What was its function? Does this source contain evidence about the topic? What is its significance? How has this source been interpreted by others? What else was found with it? What does this source tell us about its society? Once these questions have been answered, and all data collected an archaeologist can begin to formulate a conclusion about his or her find.
Twelve Angry Men Essay Research Paper In
Twelve Angry Men Essay, Research Paper In the story “Twelve Angry Men”, Reginald Rose shows how making one’s own decisions is one very important aspect in life. He also showed that one’s decisions should
Analyzing An Argument Essay Research Paper Analysis
Analyzing An Argument Essay, Research Paper Analysis of an Argument In Attacking Faulty Reasoning, T. Edward Damer defines an argument as a group of statements, one or more of which (the premises) support or provide evidence for another (the conclusion). The premises of an argument are those statements that together constitute the grounds for affirming the conclusion.
Twelve Angry Men Essay Research Paper 1
Twelve Angry Men Essay, Research Paper 1. The evidence presented in court was pretty strong. A woman said she saw the boy kill his father from across the train tracks through a window. A man in the apartment below the boys said he heard the boy say ” I am going to kill you, ” and then hear a body hit the ground. After that the man ran to the door and said that he saw the boy running down the stairs.
Philosophy Truth Essay Research Paper Truth That
Philosophy: Truth Essay, Research Paper Truth! That is a word that philosophers have been arguing about for a good while! Truth is a state of mind free of error, a state of mind, which is an accurate reflection of things in existence, of the things about you. Truth is unchangeable; it is ageless and constant.
Acculturation And Assimilation Essay Research Paper Acculturation
Acculturation And Assimilation Essay, Research Paper Acculturation and Assimilation Culture deals with thoughts, norms, and productions of a certain people. These modes are communicated among humans and not passed down genetically. Therefore, culture is the base from which the study of acculturation and assimilation use to trace similarities with other cultures.
OJ Simpson Guilty Essay Research Paper OJ
O.J. Simpson: Guilty Essay, Research Paper O.J. Simpson: Guilty This paper attempts to prove that O.J. Simpson is guilty by giving evidence from both sides, and statements made by witnesses.
12 Angry Men Essay Research Paper Every
12 Angry Men Essay, Research Paper Every man put on trial is considered innocent until proven guilty. In 12 Angry Men this theory can almost be considered false to the jurors involved in this murder case. But one man can be credited with sticking to the innocent until proven guilty theory that most likely saved a man?s life.
Modern Science Is Bullshit Essay Research Paper
Note: Less of an essay, more a branching statement. Recent medical experiments by some distiguished doctor person reveals that sun-light is actually good for your skin, despite medical evidence
Ufology Essay Research Paper In our discussions
Ufology Essay, Research Paper In our discussions about UFOs and in browsing the web, IUFOS encounters, again and again, the same fallacious lines of reasoning being used to justify a belief that aliens are visiting the Earth. In this column I will discuss the errors in these arguments.
Logic
– Features Of Argumentation Essay, Research Paper Features of Argumentation The logic of everyday argumentation should be based upon common data or information that is accepted by everyone. A warrant need to be used in order to relate the evidence that is presented in an argument to the claim that is being made.
Kate Essay Research Paper 2 Trace Edna
Kate Essay, Research Paper 2. Trace Edna Pontellier’s awakening. Edna awakening comes very soon in the story, because first of all Edna never feels connect to the wealthy Creoles of New Orleans. The whole life style of the Creoles just never fits to her and the type of person she is. Then on vacation, Edna starts to fall for a man named, Robert Lebrun.
Pacific Vortex Essay Research Paper Pacific VortexBy
Pacific Vortex Essay, Research Paper Pacific Vortex! By Clive Cussler Interviewer: Hello. I am here with Dirk Pitt, the death defying adventurer and deep-sea expert. He has just been into the depths of the Pacific Vortex and-
Beowulf An Epic Essay Research Paper Beowulf
Beowulf: An Epic Essay, Research Paper Beowulf: An Epic Numerous characteristics of this poem validate claims that it is an epic. Obviously indicative of this poem s epic nature are its boasts and battles. Beowulf s boasts begin as soon as he arrives on the Danish shore when he justifies his presence there by giving evidence of his worthiness to fight Grendel.
Role Of Faith Essay Research Paper Role
Role Of Faith Essay, Research Paper Role of Faith Society’s investigation for adequate evidence to sustain rational belief in God may seem unsatisfactory. Throughout history, people have been appealing to reason and looking for evidence to substantiate these beliefs. However, we have not yet taken into consideration the role of faith.
David Hume Essay Research Paper In reading
David Hume Essay, Research Paper In reading the ideas of David Hume, I have came to believe that he was telling us the miracles don?t exist. They are sort of a ?Mission impossible.? We
Proposal For Reparations Of African Americans Essay
, Research Paper Proposal for Reparations of African Americans Teresa Burk Due to the fact that many African-Americans cannot trace their genealogy back more than three generations, It would be extremely difficult to distinguish
Spiritual Journeys Essay Research Paper The Tale
Spiritual Journeys Essay, Research Paper The Tale of Saigyo and The Inferno both trace the unique journeys of two interesting figures, Saigyo and Dante. The two journeys are differing in that one is a journey through the life of a Buddhist monk, and the other is a journey through the different circles of hell.
Young Hunting Essay Research Paper I finally
Young Hunting Essay, Research Paper ?I finally shot my first bird!? I said after I got the bird in my hands. I was very excited. I hunted almost all my life and finally shot something. I hunted and still hunt because I enjoy going out in nature, to relax, and learn new skills like finding the trace of an animal. Going out hunting is exciting because it is one of my favorite hobbies.
Silas Deane Essay Research Paper Mysterious Death
Silas Deane Essay, Research Paper Mysterious Death of Silas Deane The authors of “The Strange Death of Silas Deane: The Problem of Selecting Evidence.”, James West Davidson and Mark Hamilton Lytle explore the skill of
Criminal Justice Essay Research Paper The criminal
Criminal Justice Essay, Research Paper 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.
Memory Essay Research Paper Memory is the
Memory Essay, Research Paper Memory is the process of storing and retrieving information in the brain. Memory is viewed as a three-step process, which include sensory memory, short-term memory, and long-term memory. Along with memory there is also forgetting. There are two types of forgetting, availability and accessibility.
The Cycle Of Never Ending Cause And
Effect Essay, Research Paper The Cycle of Never Ending Cause and Effect There is no such thing as first or second, or as cause and effect. Humanity has constantly searched for the beginning of things asking questions
Adam
’s Song Essay, Research Paper Adam’s Song I never thought I?d die alone I laughed the loudest who?d have known? I trace the cord back to the wall No wonder it was never plugged in at all
Origins Of Tennis Essay Research Paper Historians
Origins Of Tennis Essay, Research Paper Historians trace the origins of tennis back to the Stone Age, when humans first used clubs to hit rocks back and forth over barricades of dirt and stone. The next sign of tennis development was in the form of handball played in ancient world of Greece, Rome, and Egypt. However, these Herculean atheletes did not have a name for this pastime.