This is a dissertation chapter in Science:
As history is remembered, there is a great deal riding on the turn of the twentieth century. Understandably the turn into this new era came to be known as the century of science and for no better reason than the latest growth in our technological advancements. Along with this came a new scientific detection, uncovering and devoting the change in technology to the deterring of crime and the capturing of criminals. This true systematic footing gave way to a new approach in crime identification and the results that followed shocked the world, as the birth of forensic science came about.
Advancements in forensic science are constantly developing through the application of evidence and the growth of technology. The factual scientific evidence that is gathered at each crime scene must be understood as solid evidence, given that a suspect can be granted freedom or confinement because of the applied techniques used for or against his case. Because forensics provides the most accurate point in investigation of a crime scene, we must understand that the best way to identify criminals is through the application of forensic science.
In 1887 the world of crime was given a new detective, a detective who had the ability to solve, and explain why and how crimes were created. A fiction novel produced by Sir Arthur Conan Doyle gave creation to the greatest of all fictional sleuths Sherlock Holmes (Doyle). Holmes discoveries and abilities to rationalize with crime gave exponential growth to the world of criminal investigation. It was an era of trial and tribulation, but in the imagination of Sir Arthur Conan Doyle a fictitious forensic scientist paved the way for criminal investigation. Sherlock Holmes was notorious for setting the prime example for using criminal methods along with tactics such as the well known magnifying glass in the search for “clues”. Even before the ingenious deductive reasoning of Sherlock Holmes, forensic science has grown from its beginnings as early as the 700s. The Chinese were renowned for beginning the work of fingerprints in reference to the identity of documents and clay sculptures (Eckert 45). From this discovery criminal investigation took a dynamic progress towards the application of forensic sciences.
The 1800’s provided substantial growth including the use of questioning criminals in the approach to solving the crime. This decade also saw the development of testing in different methods in an advancement to recognize the presence of blood as well the use of photography to preserve the identification and documentation of the crime scene (History of Forensic). It was not until 1888 when the use of forensic science was actually applied to the corpse of Jack the Ripper in reference to the discovery of wound patterns or the methods used in his murders. Doctors in London were given permission to examine the body to further understand the reasons behind his murders. From the 1800’s into the turn of the next century forensic science revealed its true reasoning’s and recorded an advancement in the field for every year from then on out.
Forensic science over the last hundred years has given insight into the world of crime and has placed a hindrance on crime itself. In the early 1900’s forensic specialists were for the most part self-taught, with the motivation that there were no schools or areas that emphasized the practice of such an application of sciences (Eckert 27). It was not until the 1930’s that such an approach towards forensic investigation actually established an academic discipline. The changing efforts of forensic science lead to an astonishing amount of new discoveries throughout the 1900’s. Establishments of microscopes used for bullet comparison in the 1920’s allowed for investigators to accurately match a bullet to the gun it was released from. Along with this discovery came the development of the absorption-inhibition ABO blood typing technique in 1931 and the long waited invention of the breathalyzer for sobriety test finally arrived “History of Forensic”. The late 80’s saw the biggest change in forensic science history, the birth of DNA testing to accurately solve a crime and vindicate an innocent suspect. DNA testing grew to be the most predominant certification, accreditation and stable testing in the application of forensic sciences in the court of law (History of Forensics). The dawn of a new science was here at last and the problem behind criminals at large would finally come to an end.
Currently as a freshman attending the University of Northern Colorado, I intend to double major in the fields of criminal justice and chemistry, with an emphasis in forensic science. I have always had a desire to work in the field of forensics to develop technologies that will further the study and application of science to the law. Over the past two years I have worked with the Aurora Police Department (APD), and the coroners’ office in furthering my knowledge in the study of medical jurisprudence or forensics. While working with the APD I established the opportunity to collaborate my efforts with the Criminal Scene Investigation unit (CSI). While there I was given the chance to meet many of the officers who worked in that department, including forensic analysis detectives and the crime scene detectives. I was put through a series of tests including a polygraph test (lie detector) and a series of handwriting analysis. While with the CSI unit I spent much of my time in real life scenarios and experienced first hand the initial process of the crime scene. For example, the initial search of the residence is crucial for the safety of the officers at the scene, and as well the importance of maintaining the original structure of the evidence. Maintaining a “clean” crime scene will provide for undisturbed evidence and the protection of the officers arriving first in case of any threatening dangers.
I witnessed many cases, some of which are still pending, and visited a handful of autopsies revealing information dealing with cause of death. In working with those cases I learned that all deaths are treated as murders until proven otherwise. In certain scenarios dealing with death the officer in charge of that scene would remove a hair strand from the victim and take it to the lab for examination. At the lab the forensic scientist would examine the hair follicle for a built up source of protein. This process was used to identify whether or not the victim struggled, because as your body is in a state of helplessness it produces and releases a chemical that causes a bonding agent (protein) to form around hair follicles and if so then the case was usually taken as a murder. I worked along side many of the investigating task forces, including homicide, fraud and white collar crimes. This internship has proved to be invaluable and will continue to enhance my knowledge and interests in the aspect of criminal scene investigation.
Forensic science or medical jurisprudence has an extensive array of applications dealing with crime and law, which prove to be of most value in the developing of technologies to further the scientific gathering and recording of evidence. Forensic science deals with many modern day indecencies in relation to civil cases including forgeries, fraud and negligence. Forensics is also used in everyday scenarios including the determination of any violations in the use of food markets, the production of medicines, the evaluation of drinking water, establishing whether it meets legal purity, and determining that the emissions of automobiles are at acceptable levels (Kenny 23). On an international level forensics will oversee the production of Nuclear Non-Proliferation Treaty and investigations of any establishment or creation behind nuclear weapons. Although forensics does deal with a large variety of applications the most common and well known are those that deal with a victim, including robbery, kidnapping, assault, rape and murder (Forensic Science). Of these futile crimes an examination of the victim or the evidence present is an essential requirement, foreseen as being of utmost importance in the closing stages of the trial.
With each murder the large question at hand is the cause of death. In dealing with the victim the individual who conducts an examination of the corpse or autopsy is the medical examiner (Forensic Science). Also known as a coroner, the medical examiner’s job is to study the body or victim to determine type of death (natural or unnatural), cause of death being gunshot wounds or sever trauma to the skull and relativity of death to argument at trial. After this information is gathered along with the past medical history of the patient, the examiner establishes a report and provides a copy for the district attorney to provide as evidence for the case at trial. The medical examiner starts an examination by taking into account the recent guided expertise or retrieved information that has been established at the crime scene. Because there are an extensive number of ways in which a person can die, it is necessary for the medical examiner to understand the broad study of structural as well as functional alterations that can occur to a body due to injury (Marriner 67). A medical examiner usually specializes in forensic pathology. Along with a certain specialty an examiner tends to acknowledge oneself with an extensive amount of training and attends a credited university in search of a doctorate.
Forensic science includes many investigative areas, including pathology (examination of body tissues and fluids), toxicology (study of drug related substances), and odontology (the examination of teeth). Along with theses three main examination principles come a few areas of natural study including psychiatry, anthropology, biology, chemistry, and physics (Saferstein 67). Although the natural areas of study are not as pertinent to the actual application of forensics they still provide for a strong approach to guided solutions and how certain crimes are committed. Forensic science strongly depends on the contents included at a crime scene, through precise and accurate measures in the discovery of evidence. In addition to the investigating areas of examination, there are a number of other methods used in the approach to solving the crime. They consist of: ballistics, cause of death, disputed documents, DNA typing, explosives and fire, fingerprinting, forensic anthropology, psychological profiling, identification of remains, serology, time of death, trace evidence and voice prints (Evans 14). Although all are important for accurately determining the cause of death, this report will touch base with all, but will provide for more information on some than others. With every applied science come representatives who have acquired a degree of expertise and a broad area of knowledge to each of the related fields. Individuals of this nature are absolutely imperative to the medical examiner and the diagnostics of the body.
Each of the three main areas of study are linked to the initial examination of the body. First of which and most commonly used in the application of forensics is pathology. Used for a variety of different reasons pathology is the general examination of body tissues and fluids. Primarily in association with post-mortem chemical changes and changes in connection with wounding. (Davies 56). For example when a body is found at a crime scene with no known cause of death, different methods will be used in the examination of the body itself and the fluids of that particular body. With an examination of the body pathologists will be able to determine the time of death and will develop suitable evidence pertaining to the cause of death.
Along with the relationship binding the time of death to the cause of death comes a perpetual area that highlights the method used at the crime scene. In the late seventeenth century, a chemist by the name of Johann Metzeger developed a method that would clarify if there was any use of arsenic (a poison used in the late 1700’s into the next century) in any given murder (Evans 230). Prior to this scientist of all types would baffle over a death, uncertain to say whether it was of natural or unnatural causes. Metzeger discovered that if a substance containing arsenic was heated and a cold plate was placed over the heated substance a thin layer of arsenious oxide would form on the plate. Although this discovery led to the detection of arsenic in food, it bore no direct relationship between whether or not the poison had been consumed by the body.
This initial discovery gave way to a detection of arsenic located in the corpse. A Dr. Valentine Rose of the Berlin Medical Facility in 1806 found that if he were to cut up a corpse’s stomach and boiled its contents to filter any remaining flesh, he could treat it with nitric acid which had the effect of converting any presence of arsenic into arsenic acid “Drugs and Firearms”. By doing so allowed for the remains to be subjected to Metzeger’s cold plate phenomenon.
This scientific study was taken one step further when a middle-aged London chemist named James Marsh invented a suitable means of detecting even the smallest amounts of arsenic. His method was similar to the original method of Metzger’s cold plate, but instead required the use of a U-shaped tube which gave way for only the smallest secretion of vapors which exited through a small nozzle. The tested material was dropped onto a zinc plate and then covered with sulfuric acid. If any arsenic gas was detected, then as it passed through the glass tube its residue would form a layer in the circular part of the tube “Drug and Firearm”.
This method invented by James Marsh is still used today in a refined form. Now because arsenic is not the only potent poison in the hands of criminals, others such as strychnine and cyanide need to be made aware of so industrial chemicals can find a relationship between reactions. Although the study put forth in the discovery of toxicology was long and stringent, there were only approximately 28 homicides dealing with toxicology recorded in the united states in 1996 “Drugs and Firearms”. Yet with this discovery there still are individuals who dare test the James Marshes creation of arsenic identification or more appropriately known today as the lab of forensic analysis.
A human corpse can be twisted, tangled, plunged into a raging river and even burned, and not much of its components will outlast the teeth after death. Because of this, scientists have become quite familiar with identification through means of odontology. As a matter of fact many times it is the case that at certain crime scenes the only means of identification consists of the teeth. Arguably it is said that just as fingerprints have no identical match neither do teeth given that there has never been a recorded match, but one may still exist (Bennett 117). As well as fingerprints, teeth tend to wear and distort from the original recorded data that was collected during childhood years. Because of this it is vital to have both ante- and postmortem means of identification for a successful identification to take place (Heras 57).
Throughout the world today over two hundred different tooth charting methods exist. The universal approach used in most developed countries including America includes a count from the upper right molar to the lower left molar totaling 32 teeth (Evans 142). Because a odontogram or dental grid is created by recording five visible surfaces, the likelihood of there ever being exactly two identical matches is slight. As well as serving for identification of a unidentifiable corpse, the recorded odontological features also provide or common ground in identifying criminals if bite marks should exist at a crime scene. In many cases a bite mark may be the apparent evidence linked to the conviction of crimes such as burglary, homicide, child abuse and rape. In fact as the statistics report since 1992 there have been one hundred and ninety three reported cases, dealing with odontology (Weigler 1).
As of the late eighties The American Dental Association (ADA) sought out a means of future identification, by inserting a coded micro disc onto an upper molar. On each of these micro chips a twelve digit code is embedded, which can be read and matched by a computer. This code contains information about an average citizen’s personal traits. Teeth also are used for the recognition of an individual’s age, by measuring the growth of the dental tissue surrounding the tooth. Because teeth wear down from constant use the accuracy in recording the appropriate age lessens once the tested individual reaches age 25.
Of the previous discussed methods used in crime scene investigation, ballistics deals around a broad spectrum of projectiles in motion and what cause will effect that motion. When the term ballistics is brought up in forensic investigation it has created a definition of its own that deals primarily with the study of firearms and bullets (Heard 74). In recorded history it is known that the first hand gun originated in approximately 1200 A.D. Etched into the barrel of each handgun is a spiral grove that improves the aim of the handgun, by placing a spin on the projectile and stabilizing its motion. It is exactly this groove that allows forensic scientists to compare and identify the relationship between each bullet and handgun. This process known as rifling leaves a special mark called striations on the surface of the bullet and allows for this method to be used (Giannelli 195).
Because each barrel is manufactured differently it is possible to identify if a certain bullet was fired from a certain gun. Of course there are numerous numbers of bullets for each gun, but the variations from bullets fired from each gun is immediately apparent. This process of ballistics is manageable because each gun is manufactured separately. Given that each time a new gun is created the same tool that created the last gun would be used for each remaining gun. Because the tools to make the barrels are worn down immediately with each succeeding gun, it would be impossible to exactly in code or etch the same pattern twice (Evans 3). On top of that each gun will hold its pattern allowing for a direct comparison to be made to each bullet fired.
One impartial argument that can be made in determining and matching the gun to the bullet is the fact that when a bullet is fired, generally it is fired with meaning to strike. Because of this if the bullet were to come in contact with a hard bone or other material, this could cause the bullet to become distorted and in turn create a problem in matching the bullet to the gun (Iabinovia 131). But with each fired bullet a casing or shell is released into the crime scene making it more profitable to use for evidence. Just as with each bullet the shell as well is given a marking caused by the firing pin which is released by the trigger embedding its own marking onto the back of each shell. A shell is composed of a casing and a soft metal cap that is struck by the pin to create an internal explosion causing the bullet to release from the shell down the barrel and swirling through the air. Before the discovery of smokeless powder with each firing of a weapon the GSR or gun shot residue was left behind on the shooter’s skin which could be tested through chemical processing. Because an array of household products contain nitrate which is the substance that is left behind after the firing of the weapon, that method has been then since thought over.
With every crime scene that deals with a death whether it be a suicide, or murder, the main question at stake is the cause of death. Along with the first analytical approach in investigating a victims death, there must reside conclusive evidence for three questions. Who is the person? How long has he or she been dead? What was it that caused the death? Even before science took an interest in crime, the puzzling phenomenon that had baffled even the most intellectual forensic detectives was the cause of death (Petschel 82). Determining whether or not the cause of death was an accident out of clumsiness, or a plotted murder establishes whether or not there will be a charge filed and a suspect sought. For example, case dealing with a husband and his wife where the husband claims that his wife fell to her death down a flight of stairs, yet with the autopsy showing that her injuries are inconsistent with that type of fall may lead investigators to believe otherwise.
As talked about earlier, the pathologist now is the sole investigator of determining the cause of death. By examination of body fluids and tissues the medical examiner can narrow down the evidence to what had caused the victims death and answer the three important questions that reside in finding solid scientific evidence. With the knowledge to discover how, why, and for what reasons a person has died, gives science only an extended parameter of detection (Rainio 171).
Throughout the world of forensic detection our differences as individuals are noted by the color of our hair, or our eyes, our height and our weight. Each of these characteristics gives others a guideline to follow when determining how one of us may differ from the other. At the scene of a crime our characteristics must be more identifiable than just a visual concept to follow. There are a handful of ways to determine whether the questioned suspect was at the crime scene. The use of visual aid might come in play, for instance a neighbor may notice an unusual individual entering the house next door, and later hear that a burglary took place at the same residence that she had noticed the suspicious felon. The neighbor can provide the police with the initial evidence pertaining to characteristics of the individual. This is a grand initial step in the process of investigation, but again the solid scientific evidence must be more concrete than the word of one witness.
In 1911, biochemist Phoebus Levene discovered the long waited concrete evidence that will provide for a solid investigation, as will hold up in the court of law as unyielding evidence. It was through the understanding that each individual cell has a nucleus containing nucleic acid. It was also discovered that there are two types of nucleic acid, one known as ribonucleic acid (RNA) and deoxyribonucleic acid or more commonly called DNA (Evans 55). This proposed theory stated that within each nucleus is a set of twenty-three pairs of chromosomes made up of DNA. It was later discovered that this phenomenon was possible given that your genetic code, or DNA strand is embedded by one chromosome of your father’s sperm and one chromosome from your mother’s egg (Gans 168). This breakthrough in technology would soon lead to a grand conclusion and even further established evidence.
In the 1940’s it was determined that a DNA code was a life strand and not only could it identify an individual but it was also the genetic makeup that gives us our personal individual traits. A DNA strand is a lot like a tutorial in a video game or the index of a book. Just as an index or tutorial is unique to its own book or game, a DNA strand is the same for us. It was determined around the 1950’s that there are four isolated chemicals that make up our genetic code, adenie (A), guanine (G), cytosine (C), and thiamine (T). Like rungs of a ladder each are strung together to provide for our genetic makeup. The key to the placement of each individual chemical is mapped out as having (A) always joining with (T) and (C) always attaching with (G). In turn an example of a section of our life line would be as follows:
A-C-T-T-G-A-C
T-G-A-A-C-T-G
Even though the same genetic structure is created to be universal because each of us has the same body parts and organs, the linking section will vary from individual to individual. As a sample of DNA is removed from one individual it can be mixed with a restriction enzyme that will remove a strand or “piece of the code” at a particular sequence. This stand is then placed in a gel and an electrical current is passed through it separating the fragments according to size. Once complete the DNA structure is removed from the gel by a nylon membrane called a blot. This code is then treated with a radioactive genetic probe which will attach the polymorphic DNA fragments (Gans 212). DNA can be retrieved from a large number of samples but the most common are blood, hair, and semen. After a series of comparisons, scientists can tell if the DNA removed from the crime scene is a match with the suspected criminal.
It was once said that “nothing has more greatly enhanced the cause of crime detection than the discovery that no two people have the same fingerprints.” In 1879, a clerk at the Prefecture of Police in Paris, named Alphonse Bertillon produced the first systematic approach of identifying one individual from the next. A simple characteristic, such as an individuals hair color provides for an accurate difference between two individuals. Yet when evidence at a crime scene is discovered the simple characteristic will not hold stable, in proving the suspects guilt in the court of law. Bertillion’s method was based on the measurement of 243 separate lengths of an individuals body (Evans 90). Rather surprising, Bertillion’s method was quite accurate and became well known across the land. But it was sure to be condemned almost at birth by another means of identification, this one foolproof. With such a brilliant discovery, every man began to reason amongst themselves in awe, not understanding how one individuals fingerprint could be dissimilar from the rest. Even before there time fingerprints were used as a means of identification, in fact this individuality had been long recognized in such civilizations as China and Babylon. In the book of Job a passage reads, “He sealeth up the hand of every man that all men may know his work.” The idea of all men being similar by nature and no one could be accurately identified just by their fingerprints, was settled at another man’s curiosity. A Dr. Henry Faulds, published a letter in Nature, a British scientific journal that sparked the identity of fingerprints. Intrigued by finger impressions on fragments of ancient pottery, Faulds became interested in the idea that these so called fingerprints could be used as a method of identification. And so the modern fingerprint analysis began, and the excitement was noticed by the debate in Nature, and the first serious study of fingerprints began.
After scientist discovered that fingerprints were not inherited and that even identical twins have different ridge patterns, the classification of fingerprints were put into three groups; arches, loops, and whorls. Even more so fingerprint impressions fall into three basic types: latent, visible, and the plastic or molded print. By far the most common is the latent print, which is invisible to the eye, but is formed by sweat from the hands themselves or the unnoticed contact between the fingers and the glands located on the other parts of ones body. A latent print is particularly faun of such surfaces as glass or polished wood. The second type of print and the most legible kind is held together with the stained markings of blood or ink. This type of print known as the visible print is a rarity at a crime scene. The last print and also very rare to find is the plastic or molded print. This print is made on a soft surface, such as cheese, soap, or putty (Beavan 74).
Along with the different impressions that can be formed by a fingerprint, comes a variety of methods used to examine the prints. There are a number of ways to inspect a print, but the most common is the use of a black powder or organic substance. With this black powder, the investigating officer can sprinkle some shards over the item that is being examined, and then run a magnet over the powder to remove the excess powder. After the powder has absorbed into the detailed ridges on the fingerprint, the officer can remove the print with an adhesive strip, to later be tested and compared to others (suspect identities). On certain surfaces, such as checks, or security documents an iodine-fuming process is best to use, to lift the print. This new means of identification brought forth a dramatic increase in the criminal apprehension.
With every body discovered, the first question at the crime scene asked is “Who is the person?” This is of great importance given that in most murder cases the victim is normally killed by someone they know. It is exactly this reason why murderers go to great extents to conceal their victims identity. Bodies in general are very difficult to dispose of, bulky and cumbersome, they tend to float in water, resist fire, smell awful, and are usually full of clues as of the persons identity. Of these clues, some such as bones and teeth merit individual consideration and are dealt elsewhere in this paper. In the initial process of discovering a body, putting names to a few scrapes of remains has frequently provided forensic science with its greatest triumphs.
Linking the mystery of a unknown body to the identity of one individual, working with barely a handful of human matter is an astonishing accomplishment. Our bodies are unique to us and do have distinctive characteristics that provide information on our beings. These distinctive characteristics include: fingerprints, odontology (bite marks), voice prints, and serology (blood analysis. Although three of the four listed have traits that are exclusive to each individual, serology alone provides information on our blood types that can be common amongst one another. The average human being has about ten pints of blood gurgling through his or her system at any given time (Bennett 143). As of 1875 scientist realized that there were indeed various types of blood and that even though the visual characteristics looked the same, the genetic makeup was vastly different.
In 1901 an Australian-born biologist named Karl Landsteiner standardized the grouping system and coded our blood to today’s present form. This process was done by separating the serum in red blood cells in a centrifuge, and then mixing the serum with blood cells from different individuals. Landsteiner noticed that if he was to mix different blood cells with one another a different distinctive reaction would occur, rather than if he were to mix the same blood cells from two different individuals. In two separate processes the blood cells of one serum would attract to one another and the blood cells of another serum would repel one another. Or in other words one group of cells agglutinated-or clumped together-the other didn’t. Landsteiner was sure of his conclusion and labeled the two blood variations A and B. Not long after he made his stated position, he discovered a third blood type that as well reacted differently from both A and B. He named this blood type C, which soon became known as O (Bennett 145). One year later Landsteiner’s assistant discovered yet another type of blood that did not agglutinate with either A or B. This new blood variation was labeled AB, and thus the four blood types were identified. The next great advancement in the understanding of blood variations came in 1949, when two British scientist concluded that the nuclei that are found in female blood cells, will generally contain a distinctive structure that is rare in males.
These discoveries have lead the way in criminology and in the understanding of different blood variations. When blood is found at a crime scene, investigators are now able to determine if the presence of this unknown substance can identifiably and accurately be labeled as blood. This process is done by the use of a Kastle-Meyer test, which uses a solution of phenolphthalein that will turn pink if it comes in contact with blood. After it has been established that the substance is blood, another test known as the precipitin test can be preformed to establish weather or not it is human blood and not animal blood. Lastly, with the use of the processes listed above the blood can be grouped into its given classification, A, B, O or AB and then determined weather the sample it came from is male or female. For all of these reasons, blood is one of the most reliable and solid evidence found at a crime scene.
With the discovery of a body it is crucial that investigators determine the time of death. In doing so there are three traditional methods used in determining the length of time that the corpse has been dead: rigor mortis, hypostasis, and body temperature. None of which are completely reliable given that each of with can be hastened by a number of factors. Rigor mortis usually begins to set in approximately three hours after death, causing muscle tension that begins in the face hand slowly works its way down the entire body. The process, once initiated usually takes about twelve hours to travel through the body and approximately thirty six hours for the body to return to its normal state.
Hypostasis will also develop in a regular time sequence, just as rigor mortis. Once the heart stops mixing the plasma and the cell begin to settle like the sediment in a fine glass of wine the skin will begin to change colors in approximately thirty to sixty minuets. This process begins with the cells settling and then releasing from each of there individual capillaries, and enter the body. Depending on the position of the body at time of death, will depend on the area of discoloration. For example if a body is found dead on its back, gravity will take effect and the process of hypostasis will begin the discoloration across the individuals back (Snyder 74). In addition to the information provided by the process, this will also help investigators accurately decide the position of the body at time of death.
The third method used in determining the time of death is body temperature. When oxygen is no longer fueling the body and keeping it warm, the temperature falls at a rate of approximately one degree per hour. There can be a vast significance to the temperature of an obese individual compared to that of a thinner person. As well the temperature of the room where the body is located can create a difference in the average temperature of the body over a lapsed period of time. A universal formula is used when determining the time of death: normal temperature (98.6 °F) – body temperature / 1.5 (Evans 217).
In determining the time of death all factors must be 100% accurate to report an accurate time of death. Generally the approximate time of death will provide for an overall accurate decision on when the body had died. Listed here are then the conventional means of establishing an approximate time of death. Of course science is continually developing new improvements that will further the listed processes.
“Every contact leaves a trace.” So said the great French criminologist Dr. Edmund Locard. Every time a crime occurs involving physical contact, there is sure to be a “clue” or identifiable trace of evidence left behind. Each time a perpetrator commits a crime he will either leave something behind or take something along with him, often it is both. The most common items to be left at a crime scene are things like, hair, fibers, grit, powder, flakes of skin, a button or any other of countless items. With the evidence gathered it is crucial that the investigating officer handles and retrieves the evidence with great care. By its nature trace evidence is very minute and very easy to overlook (Nicekell 122). Only the most precise and meticulous examination will uncover all that there is to be found.
At each crime scene the trace evidence that is worth gathering may be invisible to the naked eye. For this reason, the handheld magnifying glass, although forever linked with images of Sherlock Holmes, still remains to be the single most useful piece of scientific equipment available to an investigator. The magnifying glass began its roots with the birth of criminal investigation, but gave light towards the invention of a compound microscope, which was invented in 1590. With even the newest technology of its time a simple reflected light microscope could only enhance an image up to a factor of one thousand times its size. It was found that even at such a great magnitude there was still need for greater magnification. In 1924 a French physicist Louis de Broglie first suggested the idea of a scanning electron microscope. Although a little ahead of his time Broglie gave substantial research in the process before it finally became fully operational in 1935. This new technological achievement would scan an image with an electronic beam and retrieve information which generates electronic emissions about the sample’s contours (Nickell 132). If that not alone stands above anything of its time, the microscope would produce an image up to 150,000 times its normal size as a three dimensional object. This technique is particularly useful in comparing evidence like paint fragments, fibers, paper, and wood. As well the microscope can enhance the image and provide high resolution photomicrographs as use in court cases.
The next question at stake is what is the unknown sample made of, and with our answer came two German scientist, Robert Wilhelm Bunsen and Gustav Kirchoff, who discovered the principle of spectrometry. The two scientist discovered that with each individual atom came a series of their own signature, providing a method of identification just as our fingerprints do for us. By passing light through a substance it is possible to produce a spectrum, which the spectroscope will reveal a series of dark lines called absorption lines that can be measured at different levels of intensity (Nickell 134). Because of this it is possible to identify all manner of different substances.
Forensic science as applied today is a highly technological field using electron microscopes, lasers, ultraviolet and infrared light, advanced analytical chemical techniques and computerized databanks to analyze and record evidence. The future of forensics is in store for a tremendous amount of change through the approach of investigation and application of evidence. Forensic science has given birth to a new world of technological advancements, through the applications of DNA, the applicability of ballistics, the social structure of fingerprinting and the solid approach of all other investigation methods. It will be understood that as the advancements of forensic science strengthen, the tendency for any given individual to walk free from a crime will weaken. Because forensics provides for the most accurate position in investigation of a crime scene, we must understand that the best way to identify and prove the guilt of a criminal is through the application of forensic science.
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