Реферат: Forensic Science Essay Research Paper Forensic Science

Forensic Science Essay, Research Paper

Forensic Science, also known as Forensics, is the application of

science to law. It uses highly developed technology to uncover scientific

evidence in a variety of fields. Modern forensic science has a broad range of

applications. It is used in civil cases such as forgeries, fraud or negligence.

The most common use of forensic science is to investigate criminal cases

involving a victim, such as assault, robbery, kidnapping, rape, or murder.

Forensic science is also used in monitoring the compliance of various

countries with such international agreements as the Nuclear Non-Proliferation

Treaty and the Chemical Weapons Convention and to learn whether a country

is developing a secret nuclear weapons program. It can help law enforcement

officials determine whether any laws or regulations have been violated in the

marketing of foods and drinks, the manufacture of medicines, or the use of

pesticides on crops. It can also determine whether drinking water meets legal

purity requirements.

The medical examiner is the most important individual in an

investigation of a crime involving a victim. It is the responsibility of the

medical examiner to visit the crime scene, conduct an autopsy (examination

of the body) in cases of death, examine the medical evidence and lab reports,

study the victims history, and put all the information together in a report to be

turned in to the district attorney.

Medical examiners are usually physicians specializing in forensic

pathology, the study of structural and functional changes in the body as a

result of injury. Their training and qualifications most often include a medical

degree and an apprenticeship in a medical examiners office.

In the field of forensic science, there are many subspecialties. They

include odontology (the study of teeth), anthropology(the study of human

beings), psychiatry, biology, chemistry, physics, toxicology (the study of

poisons), and pathology (the examination of body tissues and fluids). The

medical examiner may call upon forensic scientists who are specialized in

these fields for help in a crime investigation.

Toxicology is a branch of forensic science that deals with the adverse

effects of drugs and poisonous chemicals found in the home, at work or in the

environment. All drugs have toxic effect but the effect is most often minor.

The toxic effect of drugs may produce only a little discomfort or they may be

serious enough to cause death. One of the most common cases of death by

poison is arsenic poison.

Pathology is the branch of forensic science that determines the nature

and course of diseases by analyzing body fluids and tissues. Pathology is

divided into clinical and anatomic pathology. Clinical pathologists contribute

to the diagnosis of diseases by measuring chemicals and cells in blood,

sputum, bone marrow and urine. Anatomic pathologists perform autopsies

and analyze tissues taken from patients during surgery or by biopsy.

The medical examiner investigates many different types of violent

crime to determine whether a violent death was an accident, a suicide, or a

homicide. In cases involving gunshot wounds, the medical examiner looks for

gunpowder residues on the clothing of the victim and around wounds. The

information is used to determine whether the gun was fired by the victim of

by someone else.

In the case of knife wounds, the medical examiner must distinguish

between a cut (an injury that is longer than deep) and a stab wound (an injury

that is deeper than long).He must also be able to identify a defense wound

which is a cut caused when a victim grabs the knife in self-defense. Cuts are

associated with suicide. The body of the victim usually has numerous parallel

cuts which indicate hesitant wounds or repeated hesitant trials before the final

cut is made. Homicides typically consist of one deep gash.

Medical examiners are also called upon to investigate cases of

asphyxiation or death form lack of oxygen in the blood. Asphyxiation may be

caused in a number of different ways, such as hanging, which can be an

accident, homicide or suicide, or strangling which is homicide. Damage to the

victims air passage by an object in the throat or compression of a victims

chest by a person or an objector the replacement of oxygen in the red blood

cells by another gas such as carbon monoxide poisoning. That too can be a

result of an accident, homicide or suicide.

In a death involving carbon monoxide poisoning a closed garage door

and no marks on the body are usually taken as an indication of suicide. The

presence of tools around the car and grease on the victims hands is an

indication of an accidental death. The presence of a wound caused by a blow

to the head or if there is no carbon monoxide in the blood of he victim

indicates a homicide that was made to look like a suicide.

Forensic science uses sophisticated lab techniques to detect the

presence of substances in the victim, the suspected criminal, or at the crime

scene. In determining whether alcohol was involved in a crime, the amount of

alcohol in the blood can be measured in two ways. The first is to measure the

amount of alcohol exhaled in the breath of the person. This reveals the

concentration of alcohol in the person s blood. Blood alcohol level can also

be determined by blood tests, usually through chromatography. In this

method, the blood sample is vaporized by high temperature, and the gas is

sent through a column that separates the different chemical compounds

present in the blood. Gas chromatology also detects the presence of

barbiturates, cocaine, amphetamines, and heroin.

When a body is discovered in a lake, stream, river or ocean, and the

lungs are filled with water, the medical examiner must determine if the

drowning occurred where the body was found or somewhere else. A

standard microscope that can magnify objects to 1500 times their size is used

to look for diatoms. Diatoms are single cell algae that are found in all natural

bodies of water. If there are no diatoms, it can be concluded that the

drowning took place in a bathtub or sink since diatoms are filtered from tap


A scanning electron microscope that can magnify objects 100,000

times is used to detect tiny gunpowder particles present on he hand of a

person who recently fired a gun.

One of the oldest techniques of forensic science is dusting the scene of

a crime for fingerprints. In one method of obtaining a fingerprint, a technician

spreads fine powder over a surface with a brush or magnetic wand. The

powder sticks o proteins secreted by the sweat glands on the skin ridges of

the fingertip When the excess powder is removed, an outline of the contours

of the ridges remains. The print may also be chemically treated to reveal the

contours. Since no two fingerprints are the same, fingerprinting is a positive

way of identifying someone.

Other evidence that may be found at a crime scene is blood, hair, skin,

or semen. Human bite marks can also serve as evidence. Bites can be found

on the victims body or in pieces of food or gum found at the crime scene. A

forensic scientist can fill the impression caused by the bite marks with a liquid

plastic. The cast will form an accurate replica of the assailants teeth which is

then compared with a cast of the suspects teeth.

District attorneys call forensic scientists to give their expert testimony

in a trial concerning what they find from an autopsy and what they write in

the lab reports. Expert testimony is the statement given by a specialist who

has been recognized as having expert knowledge about evidence in the case.

An expert witness is allowed to give an opinion about whether or not the

evidence is valid. An expert witness may also quote the statements of other

experts to support an opinion. Ordinary witnesses are restricted to giving

statements about what they actually saw or heard.

The medical and legal approach to dealing with crimes began in

England during the 12th century. King Richard I established the Office of the

Coroner. The coroners main job was to keep a record of all criminal affairs in

the county and investigate all deaths that were believed to be a homicide or

suicide. The need for more scientific investigation of unnatural deaths became

evident and the coroners began asking doctors for help. Over time medical

schools started to prepare doctors in that specific field. In 1807, the

University of Edinburgh in Scotland instituted a Department of Legal


Early American colonists Bought the coroner system with them. As

medical involvement in investigating violent and unexplained deaths

increased, communities began requiring that coroners have specific academic

training. In 1877, Massachusetts replaced the coroners office with the Office

of the Medical Examiner, which was to be headed by a physician. Soon many

other states followed. In 1915 New York City established a program where

the medical examiner was authorized to investigate all deaths that occurred to

people who appeared to be in good health, that resulted from criminal

violence, accidents, or suicides.

Computer technology now allows law enforcement officers o record

fingerprints digitally and to transmit and receive information for quick

identification. Recent developments in technology allows scientists o examine

the deoxyribonucleic acid (DNA) or genetic material of blood, hair, skin, or

semen to see if they belong to the victim or the suspected criminal. Using

polymerase chain reaction (PCR), a lab can clone the DNA from a very small

sample of one of those substances.

Forensic science as practiced today is a field of science medicine that uses

electron microscopes, lasers, ultraviolet and infrared light, advanced chemical

techniques and computerized databanks to analyze and research evidence.

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