Download administration of justice ? ? forensic science

ADMINISTRATION
OF
JUSTICE
FORENSIC SCIENCE
I.
INTRODUCTION
A.
Forensic science is the application
of scientific knowledge and
technology to criminal and civil law
enforcement as it pertains to the
framework of our justice system.
1.
Forensic science has two
principle applications.
a.
First, is to supply accurate
and objective information
that reflects the events that
have occurred at a
particular incident.
(1)
This includes crimes
against the person or
property
b.
Second, forensic science monitors and
enforces compliance with existing
legislation. This includes monitoring:
(1)
food and water quality.
(2)
the nature, potency and
purity of pharmaceuticals.
(3)
the production and release
of industrial pollutants and
motor vehicle emissions.
(4)
the manufacture and use of
agricultural - chemicals.
B.
Forensic science is the scientific
study that is specifically designed
to assist the law enforcement
community and the judicial
system by applying science to
the law.
1.
Forensic science uses highly
developed technologies to
uncover scientific evidence
in a variety of fields.
2.
Forensics helps in crime
detection and investigation by:
a.
systematically examining
a crime scene.
b.
identifying evidence at
the crime scene.
c.
evaluating and interpreting
of physical evidence found
at the crime scene.
C.
When crimes are committed, the
person who commits the crime
often leaves behind a record
of himself or his actions in the
form of physical evidence.
1.
Forensic science is most
commonly used to investigate
criminal cases involving a victim,
such as assault, robbery,
kidnapping, rape, or murder.
D.
The forensic scientist makes use
of a wide spectrum of scientific
knowledge and skills he/she has
developed through formal
education and on-the-job training.
1.
A forensic scientist is called upon to
examine a variety of exhibits since
almost any material found at a crime
scene may be potential physical evidence.
2.
Examination may be as simple as
matching pieces of broken glass
found at the scene of a
hit-and-run traffic accident.
3.
Examinations may involve the
use of very complex instruments
of technology.
a.
For example, in the analysis
of a suspected cocaine
sample or blood sample.
II.
HISTORY OF FORENSIC SCIENCE
A.
Combining the medical and legal
approach to investigating crimes
currently practiced in the United
States today originated in 12th
century England.
1.
King Richard I established the
Office of the Coroner.
a.
Main duty was to maintain
a record of all criminal
matters in the county.
b.
Responsible for investigating
all deaths regardless of
whether it was the result of
a suicide or homicide.
2.
Over time, the need for a more
scientific investigation of deaths
became apparent.
a.
Coroners began calling
on physicians for help.
b.
Medical schools began to prepare
doctors for this added responsibility.
(1)
1807 - the University of Edinburgh
in Scotland established the
Department of Legal Medicine.
B.
The early British colonists
brought the coroner system
with them to the America’s in
the fifteenth century.
1.
Coroners were appointed by
a representative of the
crown to investigate violent
and unexplained deaths.
2.
After the American Revolution
elected officials appointed
coroners.
a.
As medical involvement in
the investigations of deaths
increased, it became a
requirement that investigators
have a specific academic
background.
b.
1877 – Massachusetts adopted a
statewide system called the Office
of the Medical Examiner, to be
headed by a physician.
c.
1915 - New York City established
a medical examiner who was specifically
authorized to investigate all:
(1)
deaths resulting from
criminal violence.
(2)
accidental deaths and
suicides.
(3)
deaths that occurred
suddenly to people
who appeared to be in
good physical health.
C.
The field of forensic science today is
one of high-technology using the most
advanced and sophisticated equipment.
Some examples of these modern
devices and techniques are:
1.
the electron
microscope.
2.
the use of lasers.
3.
the use of ultraviolet and infrared light.
4.
the use of advanced analytical
chemical techniques.
5.
the use of computerized databanks to
analyze and research evidence.
III.
FORENSIC SCIENCE AND THE
LEGAL SYSTEM
A.
Modern forensic science has a
broad range of applications in
our criminal justice system.
1.
It is used to settle issues
in civil cases such as fraud,
forgery, or damages that
are attributed to negligence.
2.
It can help law-enforcement
officials determine whether a law
or regulation has been violated in:
a.
the marketing of foods
and drinks.
b.
the manufacture of medicines.
c.
the use of pesticides on crops.
3.
It can also determine whether
automobile emissions are within
a permissible level and whether
drinking water meets legal
purity requirements.
B.
Medical examiners are requested to give
expert testimony in court proceedings
on a regular basis.
1.
Expert testimony is information
provided by a specialist who has been
recognized by the court as having
expert knowledge about evidence in
the case.
a.
Expert testimony is governed by
different rules.
2.
The average citizen is considered an
“ordinary” witness and their testimony is
restricted to statements about what they
actually saw or heard.
a.
Ordinary witnesses may not state
opinions about the facts of a case.
b.
Ordinary witnesses may not quote
statements made by other people to
support their testimony.
3.
The expert witness on the other
hand is allowed to express an
opinion about the validity of the
evidence and may quote the
statements of other experts that
support their opinion.
IV.
THE MEDICAL EXAMINER
A.
The central figure in the forensic
investigation of crimes involving
a victim is the medical examiner.
1.
It is the medical examiner’s
responsibility to:
a.
go to the crime scene
b.
conduct an autopsy of the
body in cases of death
c.
examine available medical
evidence and appropriate
laboratory reports
d.
examine the victim's
previous medical history
e.
prepare a report for the
district attorney outlining
all pertinent information
B.
Medical examiners are usually
physicians who specialize in
forensic pathology - the study
of structural and functional
changes in the body as a
resulting from injury.
1.
Their training and qualifications
generally include having a medical
degree and they have completed
an apprenticeship in a medical
examiner's office.
V.
FORENSIC SCIENTISTS
A.
Within the field of forensic science
there are many areas in which
forensic scientists chose to
specialize. Some examples of
those specialty areas are:
1.
anthropology: (the study
of human beings)
2.
forensic biology: chemistry,
and physics
3.
odontology: (the study of teeth)
4.
pathology: (the examination of
body tissues and fluids)
5.
psychiatry: (the study of the human
mind)
6.
forensic toxicology: (the study of
poisons, including drugs)
7.
toolmarks: (consists of striations
or impressions left by tools on objects)
8.
documents: (relationships
between documents and inscription)
9.
firearms: (characteristics between
firearm and projectile, projectile and
target)
10.
forensic imaging: (image fraud
detection – image analysis)
11.
latent fingerprints: (processing
latent finger prints on evidence
from crime scenes)
12.
microscopy: (pertaining to the use
of microscopes and microscopic
evidence)
13.
polygraph: (recording variations
in the heartbeat and respiratory
movements)
B.
Law enforcement agencies often
call upon forensic scientists who
are specialists in these various
fields for help in the investigation
of a crime.
1.
Forensic anthropologists
determine the sex, height, weight,
and ethnic group of a deceased
person from an incomplete body.
a.
Marks on the bones often
indicate past injuries, diseases,
and occupational stresses
suffered by the individual.
b.
Investigators can identify a body by
comparing old X-rays and the medical
history of a missing person
with the findings
of the forensic
anthropologist.
2.
Forensic odontologist’s examine
and characterize the teeth of
unidentified bodies when
fingerprints or other
identification is not available.
a.
Dental charts of missing
individuals can then be
compared with the forensic
odontologist's report to
help identify the body.
3.
Forensic pathology deals with
the postmortem investigation
of sudden and unexpected death.
a.
Proximate cause of death.
The initial injury that led
to a sequence of events
which caused the death
of the victim.
b.
Immediate cause of death.
The injury or disease that
finally killed the individual.
4.
Psychiatry, (the study of the
human mind)
a.
Involves mental illness
and disorder.
b.
Causes of mental illness
and disorder.
c.
The diagnosis and treatment of
disorders.
d.
May also be used in profiling.
(1)
Investigators can examine
certain evidence found at
crime scenes to come up
with a personality profile
of the offender.
5.
Whenever drugs or poisons
are involved in a crime, the
investigating agency may obtain
the services of a toxicologist.
a.
Toxicologists detect and
identify any drugs or poisons
present in a person's body
fluids, tissues, and organs.
b.
This type of investigation is
conducted on both the victim and,
the suspected perpetrator of the
crime when possible.
VI.
EXAMINING EVIDENCE
A.
The medical expert investigates
many different types of violent
crimes.
1.
The medical examiner must
try to determine whether a
violent death was an
accident, a suicide, or an
unlawful homicide (murder).
2.
The medical examiner must
conduct an investigation of the
crime scene and perform an
autopsy to determine cause of
death.
B.
Cases involving firearms.
1.
In cases involving gunshot
wounds, the medical examiner
will look for gunpowder residues
that may be left on:
a.
b.
the clothing of the victim.
the area around any
wounds on the victim.
2.
This information will be used to
estimate how far away the gun
was when the victim was shot.
3.
This may also help determine
whether the gun was fired by
the victim or another person.
C.
Cases involving knives.
1.
When knife wounds are involved,
the medical examiner must
distinguish between a cut and
a stab wound.
a.
A cut is an injury that
is longer than it is deep.
b.
A stab wound is an injury
that is deeper than it is long.
2.
The examiner also looks for self-defense
wounds, cuts that are caused when an
intended victim grabs the knife of an
assailant.
3.
Cuts, are commonly involved with suicide.
a.
There are usually numerous
superficial parallel cuts visible
on the body.
b.
These type of cuts indicate
repeated attempts, before
the individual was able
to make the final deep cut.
(1)
These cuts are called
hesitation wounds.
(2)
They indicate a suicide
rather than a homicide.
D.
Investigations involving asphyxiation.
1.
Medical examiners are
also called upon to
investigate cases of death
from lack of oxygen in the
blood.
a.
Asphyxiation may be the result of:
(1)
hanging, which may be an
accident, suicide, or a
homicide that could be
lawful or unlawful.
(2)
death by strangulation at
the hands of another.
(3)
obstruction of the victim's
air passage by an object
in the throat.
(4)
suffocation caused by a
gas such as in carbon
monoxide poisoning.
2.
Deaths involving carbon
monoxide poisoning in a closed
garage with no marks found on
the body usually indicate a
suicide.
a.
The presence of tools
around the car and grease
found on the victim's hands
suggests an accidental death.
b.
A wound caused by a blow
to the head and the absence
of carbon monoxide in the
blood would indicate an
attempt to make a homicide
look as if it where a suicide.
VII.
TECHNIQUES OF FORENSIC SCIENCE
A.
Forensic science uses the
most sophisticated laboratory
equipment and techniques.
1.
Forensic technology is used to
detect the presence of substances
in victims, suspected criminals,
and at the crime scene.
a.
Alcohol breath-testing
instruments are so accurate
that their results are capable
of providing evidence in
court.
b.
Gas chromatography permits
detection of alcohol and
other drugs, such as
barbiturates, cocaine,
amphetamines, and heroin.
Ion Chromatography System
2. When a body is discovered in a lake, or
river and the lungs are filled with water
the medical examiner must determine if
the drowning occurred where the body
was found or at some other location.
a.
A microscope is used to look for
the presence or absence of
diatoms, single-celled algae found
in all natural bodies of water.
b.
An absence of diatoms raises the
possibility the drowning took
place in a sink or bathtub since
diatoms are filtered from
household water.
3.
Microscopes that can magnify
objects 100,000 times are used to
detect the minute gunpowder
particles left on the hand of a
person who has recently fired
a gun.
a.
Chemical analysis of these
particles can help identify
their origin from a particular
type of bullet.
B.
Forensic examination of substances
found at the scene of a crime often
establish the presence of the suspect
at the scene.
1.
One of the oldest techniques
of forensic science is dusting the
crime scene for fingerprints.
a.
In one method of obtaining a
fingerprint, a fine powder is
spread over a surface with a
brush or magnetic wand.
(1)
The powder sticks to
proteins secreted by the
sweat glands on the skin
ridges of the fingertips.
(2)
When the excess powder
is removed, an outline of
the contours of the ridges
remains.
2.
Another method of obtaining a
fingerprint is to chemically treat
the print to reveal the contours.
a.
Since no two fingerprints
are the same, fingerprinting
provides a positive means
of identifying someone.
3.
Computer technology now allows
fingerprints to be recorded digitally
and transmitted electronically for
rapid identification.
4.
Other types of evidence often
found at a crime scene includes
blood, hair, skin, or semen.
a.
Technology now allow
scientists to examine a
persons (DNA), or genetic
material, to establish whether
they belong to the victim or
to a suspected assailant.
b.
The use of DNA for such identification
purposes is commonly referred to as
DNA fingerprinting.
5.
Human bite marks can also be
used as circumstantial evidence.
a.
Bites may be found on the body
of a homicide victim or other
objects found at the crime scene.
b.
Forensic scientists may fill
impressions caused by human
bites with liquid plastic.
(1)
The hardened cast formed
is a very accurate replica
of the assailant's teeth.
(2)
This replica can be compared
with a cast made from the
teeth of the suspect.
VIII. FIREARMS AND TOOLMARK
IDENTIFICATION
A.
Firearms examination involves
the identifying characteristics
between firearm and projectile,
projectile and target.
1.
Ballistics Microscope
This generally includes
matching bullets to the
gun that is believed to
have fired them.
B.
Toolmark identification involves
the identifying characteristics
between tools, such as a pry bar,
and objects such as a door frame
it was used to pry open.
C.
Included in this category would
be explosives and imprint evidence.
1.
The majority of physical evidence
collected concerns itself with two
types of characteristics.
a.
Class characteristics that
are common to a group of
similar objects.
(1)
All Air Jordan sneakers
have the same shape
and same tread design
on the bottom.
b.
Individual characteristics are
unique to a given object and set
it apart from similar objects.
(1)
Air Jordans worn over time
cause the treads wear to
down.
They get little pits and
gouges in them.
(2)
These little pits and gouges
are individual to a specific
shoe since no one has
walked over the exact same
surfaces in the exact same
way in their Air Jordans.
D.
The concepts of class and individual
characteristics are most important in
firearms examination.
1.
The purpose of the firearms
examination is to match a
bullet to the gun that fired it
and exclude all others.
Test Fire for Comparison
E.
Bullet Matching.
1.
Rifling gives the bullet a
signature marking that is
unique to the weapon that
fired it.
a. Rifling is the result of the manufacturing
process of the firearm and serves to put
spin on the bullet.
(1)
Rifling improves accuracy.
Probably the most common method used today to rifle barrels
is button rifling. Button rifling uses a different approach to
forming the grooves in the barrel. A button as seen above is a
very hard steel plug that is forced down an unrifled barrel.
2.
Rifling consists of lands and
groves that spiral down the gun
barrel.
a.
As the bullet passes down
the barrel, microscopic
scratches from the lands
and grooves mark the bullet.
b.
These microscopic scratches
are the result of the
manufacturing process
and are totally unique to
a particular firearm.
Hammer Forged 6-Right
Polygonal Rifling Pattern
Hill
Valley
3.
Comparison tests are made in
the lab by test firing a bullet
through the suspect weapon.
a.
The test fired bullet is
then compared under a
comparison microscope,
side by side, to the bullet
recovered from the
crime scene.
b.
The bullets are rotated until
the striations can be made
to line up, showing a match.
(1)
If the striations cannot
be lined up, the result
is negative.
F. Imprint Evidence.
1.
There are two basic types of
imprint evidence.
a.
Three dimensional impressions,
in which an object is pressed into
something soft that will retain the
impression of that object.
(1)
Stepping into mud and
leaving a shoe print
would be an example.
b.
Two dimensional impressions,
in which objects transfer an
image from one surface to another.
(1)
Paint coats the bottom of
the shoe when a person
steps into spilled paint.
(2)
It is then transferred to another surface
when the person steps in an area free of
paint.
(3)
When the shoe is removed from the
paint the paint removed by the shoe
creates a negative image of the bottom
of the shoe in the paint spill.
2.
Impression evidence is not just
used for shoes, impression
evidence can also be used with
tire impressions and toolmarks.
a.
Wheel base may help to
narrow down the make of
the car.
b.
The tread design itself can
narrow down the list of
possible cars.
(1)
Individual tire wear
will show up in the
impression.
G.
Toolmark Evidence (three types
of toolmark impressions).
1.
Compression, in which a
tool surface presses into
a softer material;
2.
Sliding, in which a tool
(such as a knife) scrapes
across a surface causing
parallel striations;
3.
Cutting, which is a
combination of the above
two types (such as a
scissor cut).
4.
All three types can yield class
and individual characteristics.
a.
Marks left on a window
frame from a pry bar
can be matched back
to that specific pry bar.
H.
Explosives.
1.
Explosives residue can be
analyzed to determine the
type of explosive used in a
particular detonation.
2.
Many manufacturers are now
putting chemical tags in their
explosives that will allow for
tracking of specific batches
by chemical composition.
IX.
FORENSIC PSYCHIATRY AND PROFILING
A.
Forensic Psychiatry defines mental
illness and disorders, what creates
them, how they are diagnosed and
how they are treated.
1.
Mental illness cases: the
individual does not function well
in reality because of emotional
fluctuations or distorted point of
view interpretation.
2.
Mental disorder cases: a clinically
significant behavior or pattern
associated with distress,
disability or significant risk
of suffering death.
B.
Diagnosis is a medical
classification that allows
for communication between
professionals, allows for
prediction of illness and
indicates the best course
of treatment.
C.
The issue of incompetency
is fitness to stand trial.
1.
The accused must
understand what is going
on in order to help in their
own defense.
2.
The three grounds for incompetency
are:
a.
emotional/psychological
factors,
b.
cognitive or intellectual
factors,
c.
and physical factors.
3.
An individual must undergo a
competency evaluation if this
assertion is made.
D.
The issue of insanity applies to
the mental state of the defendant
at the time the crime was
committed.
1.
The defendant must
concede guilt when
entering the insanity plea.
2.
The defendant claims to have
committed the crime while
mentally impaired and did not
know right from wrong or what
they were doing.
3.
The defendant must prove they
have a profound defect of mental
ability.
E.
Profiling is the process by which
a trained forensic psychologist
examines the aspects of a crime
scene to develop a description of
the personality of the perpetrator.
1.
This profile can include:
a.
age, sex, occupation,
upbringing,
b.
behavioral disorders,
marital status,
c.
the type of place the
perpetrator would live in,
d.
what type of car he drives,
e.
if he has a speech
impediment,
f.
or some other type of
disability.
2.
Profiles can tell you how
the crime was committed.
a.
Information can be learned
about the perpetrator of a
serial crime just by looking
at how that crime was
committed.
F.
Profiling works because countless
hours have been spent interviewing
hundreds of convicted criminals,
learning about their crimes, motives,
methods and personalities.
1.
These databases help investigators
in making conclusions from what
they view at a crime scene.
2.
Databases draw on thousands
of man-hours of research and
interviews and has proven to
be extremely accurate.
G. Profiling does not produce a name.
1.
It does produce a detailed
personality profile of a
perpetrator that investigators
can use to focus an investigation.
X.
QUESTIONED DOCUMENT
EXAMINATION
A.
This area of forensics involves
all special relationships that may
exist between document and
inscription and how it relates to
a person or sequence of events.
1.
This includes forgery, counterfeiting,
and handwriting analysis.
B.
Questioned document
examination involves many
areas of expertise.
1.
Included are the following
disciplines:
a.
handwriting, typewriting,
b.
photocopying and
computer printers,
c.
forgery, paper and inks,
writing instruments,
d.
computer disks,
gambling machinery,
e.
stamps (as in the rubber
pad kind)
f.
and the dating of
documents.
C. Handwriting analysis
1.
Handwriting analysis involves
detailed examination of the
design, shape and structure of
handwriting to determine
authorship of a given
handwriting sample.
2. The basic principle underlying
handwriting analysis is that no two
people write the exact same thing
the exact same way.
a.
Each individual develops unique
peculiarities and characteristics
in their handwriting.
3.
Handwriting analysis looks at:
a.
letter formations,
b.
connecting strokes between
the letters,
c.
upstrokes, retraces, down
strokes, spacing,
d.
curves, size, distortions,
hesitations,
e.
and a number of other
characteristics of
handwriting.
4.
By careful examination a
determination can be made as
to whether or not the authorship
of a handwritten document is
genuine.
D.
Typewriting
1.
Individual characteristics
are either inherent in the
machining process of a
manufactured item, or
come about through the
wear and tear in the use
of an object.
a.
All typewriters of a particular make and
model are pretty much the same.
(1)
(2)
Through use, typewriters will
develop defects that translate to
paper when the machine is used.
The defects left on the typed page
can be matched back to the
typewriter that was used to
create it.
b.
Defects in the type face can
be identified by:
(1)
letter misalignment
(2)
a letter failing to print evenly
c.
Ribbons are a major
evidentiary component.
(1)
It is possible to read a
ribbon to see what it has
been used to type.
E.
Photocopiers and Laser Printers.
1.
Photocopiers and laser
printers use the same type
of process to print a page.
2.
With a photocopier, the original
document is placed on the glass platen.
a.
By use of a reflected light the
document is exposed to a drum
covered with a photosensitive
material.
b.
The document image exists on the
drum as an invisible positive
photoelectric charge.
c.
Negatively charged toner
(a powder), is sprinkled onto
the drum, where it sticks to only
the positively charged areas to
create a visible image.
d.
Paper, with a positive charge,
passes the drum resulting in
the negatively charged
toner being transferred to
the paper.
e.
The toner is heat sealed
to the paper, creating
the printed copy.
3.
With a laser printer, the image of
the original document is held by
a computer in its memory.
a.
The document is then
sent to the photosensitive
drum by use of a laser
creating a printed copy.
4.
There are several ways to match a page
back to a photocopier or laser printer:
a.
The paper itself can yield many
clues.
(1)
Look for marks from the
belts, pinchers, rollers and
gears that physically move
the paper through a machine.
b.
How the toner was placed on and
fused to the paper may leave unique
characteristics.
(1)
Toner may clump up on the drum,
transferring smears or splotches
of toner at atime to the printed
page.
c.
Marks on the optics (glass platen,
lenses, mirrors) used to transfer
or create an image on paper might
contain unique defects like
scratches that will leave tell tale
marks on the printed page.
F.
Forgery
1.
Forgery is the false making
or material altering of any
written document with
intent to defraud.
2.
There are four basic types of forgery.
a.
Traced
(1)
There are several ways
to make a traced
forgery:
(a)
by use of overlays
(tracing paper),
(b)
by the use of transmitted
light (as with a light board),
(c)
by tracing the indentations
left in the page underneath
the original writing
b.
Simulation
(1)
Copying of writing from a
genuine article; trying to
imitate the handwriting
of the original.
(2)
Simulation forgeries are easy
to detect.
(a)
It is very difficult to copy
someone else’s handwriting.
(b)
The style will not be as fluid.
(c)
The forged writing will show
tremors, and hesitations in
letter quality.
c.
Freehand
(1)
Forgeries written with no
knowledge of the appearance of
the original; just writing off the
top of your head and passing it
off as something else.
(2)
Freehand forgeries are the
easiest to detect.
d.
Lifted
(1)
In this type forgery, tape
is used to lift off a signature,
then place it on another
document.
this concludes
Crime Scene Investigation