DNA…the Indispensible Tool
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The time period…19th Century
The stethoscope had not been invented
You are buried alive because you have a weak
heartbeat
As you wake up from passing out, you find a
grave digger above you throwing on the dirt
In the 19th century, there was no definitive way
of determining if a person was dead
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In the late 16th century, a list of tests were
devised to determine if someone was dead:
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Tongue and Nipple Pulling
Tobacco and Smoke Enemas
Insertion of Hot Pokers into Body orifices
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In the 17th Century, a system known as vitae
dubiae asylums
These places of holding bodies thought to be
dead was quite the improvement from having
hot pokers shoved in your orifices
The suspected dead were placed on cots and
watched until decay set in
Although this process was very difficult for
families, there was a huge reduction in the
number of premature burials
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This was the first of many steps in easing the
determination of death
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Electrocardiogram (EKG) – device that records
electrical impulses from the heart, was invented
shortly after the stethoscope
20th Century, the advent of cardiopulmonary
resuscitation (CPR) followed by the use of
ventilators and pacemakers which all promote
heart function after death muddied the water again
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This brought about the concept of Brain Dead, which
simply means that the brain is not functioning, but the
heart is still beating
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Someone who has a heartbeat or a pacemaker
and is on a ventilator requires the absence of
electrical activity in the brain OR determination
of loss of blood flow
Before a doctor “pulls the plug”, he/she must
ensure that there is a 0% chance of survival.
Otherwise the doctor can be held responsible
for the death
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Cause of Death – the reason a person died
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Abnormal physiological changes that lead to death
Examples: heart attack, gunshot wound, skull
fracture
Mechanism of Death- the result of the cause of
death
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Examples: exsanguinations (bleeding to death),
sepsis (infection in the blood stream), cerebral
contusion (direct trauma to the brain), subdural or
epidural hematoma (bleeding around the brain),
asphyxia (stopped breathing)
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One cause can lead to multiple mechanisms
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Example: bleeding to death (cause of death) results
from a gunshot wound, stabbing, bleeding ulcer,
bleeding lung tumor, etc.
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This is grounds for an Autopsy from a medical
examiner or a coroner
It is the job of the medical examiner to
determine which of the four manners of death
are at play:
1.
2.
3.
4.
Natural- natural occurrences, these make up over
50% of all deaths the ME sees
Accidental- occur from unplanned and unforseen
events, example: car accident
Suicidal- caused by the dead person’s own hands
Homicidal- occur as the result of another person
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In the event where the ME can not determine
the cause of death, the death is classified as
undetermined or unclassified
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Pathology is the study of diseases and their
effects on the body
Dates back as far as the 1800s
By the mid-twentieth century, many subbranches of pathology began erupting
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Forensic Pathology became a recognized branch in
1959
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FP is the study of medicine and how it applies to the law,
in particular criminal law
More than 50% of cases seen deal with disease
Performs autopsies that provide evidence to court
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13 years of college, medical school, and on-site
training to become a clinical pathologist
Serve an additional 1 year fellowship in forensic
pathology
If you are interested, see me for more details…
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Forensic Autopsy: performed for legal
documentation and affirmation
Medical Autopsy: performed at the hospital to
determine any unknown diseases associated
with the deceased
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ME will autopsy anyone who dies:
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Traumatically- occurring from accidental, homicidal,
or self-inflicted injury
Unusual- unnatural or suspicious circumstances
Sudden- within a few hours of onset of symptoms
Unexpected- occurring in someone who was not
thought to be ill
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If the physician requests an autopsy, the case
turns into a reportable death or coroner’s case
This usually occurs when death falls into one of
these categories:
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Violent deaths
Deaths in the workplace
Sudden, unexpected, or suspicious
Deaths during incarceration
Deaths unattended by a physician or medical staff
Deaths during medical procedures
Deaths during an abortion
A found body
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Designed to determine how, when , and why
someone died
Everything from debris under fingernails to the
contents of the deceased’s stomach could lend
clues to those three questions
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A decaying body will keep up to five days in a
refrigerated vault without losing valuable
structure and rigidity
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Measuring and weighing- this is the first step of
the autopsy. Consists of height, weight, age, sex,
race, hair color and eye color
Photograph the Body- both clothed and
unclothed, frontal and profile pictures are
taken, every scar, birthmark, tattoo, and
unusual physical feature is noted
Examine clothing- search for trace evidence,
damaged to clothing (may correspond to injury
to the body)
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Establish TOD- determine rigor mortis and
lividity (settling of the blood)
Take X-Ray’s- not used in every autopsy,
especially important in gunshot cases
Look for Trace Evidence- the body is examined
intensely to find any foreign material, this is the
most painstaking step in the autopsy
Examine Injuries- each abrasion or bruise is
documented on a diagram using at least two
reference points
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Lacerations – cuts and slices, these are photographed
and measured both lengthwise and depth, a search for
tool fragments is also conducted
Contusions – bruises, measured and photographed
Widespread lacerations and contusions indicate a
struggle occurred
Multiple wounds on the arm indicate a defensive battle
In some cases, an accurate count of the number of
wounds is impossible to count, in that case the ME will
estimate the minimum number of wounds needed to
make the kill
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Hesitation Wounds – often accompanying a suicide,
these are small nicks around the fatal wound, these are
indicative of someone gathering enough courage to
make the final cut
Gunshot wounds – photographed, measured, and Xrayed, the X-ray plots the path of the bullet and shows
its final resting place
X-ray of Governor
Connally’s Wrist
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Dissection is the step you see in movies and on
TV due to it being the step when the body is
actually cut open, this process follows but is not
limited to these steps:
1.
2.
3.
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6.
Making the Incision
Removing the Heart and Lungs
Examine the Abdomen
Collecting Samples
Assessing the Head and Brain
Returning the Organs and Suturing
Made on the Ventral Side
of the body
Three arms on the
incision –
Two extending from each
clavicle to the sternum
(shoulder to breastbone)
The third follows the midline down to the pubis
The ribs and clavicles are
now cut with a saw or
shears and the breastplate
is removed
May be removed sequentially, but are most
often en bloc (as one unit)
Blood samples used in typing, DNA analysis and
other uses is taken from
Heart
Aorta
Inferior vena cava
Each organ is weighed and measured
Tissue samples are taken from each organ for
testing
Stomach contents are examined for
toxicological evidence, also can determine time
of last meal
Also will take samples of ocular fluid, bile from
the gall bladder, urine, and liver tissue
Look for skull fractures and head trauma before
removing brain
Triangular section of skull removed above eyes
and brain is observed in situ (in place) before
being removed
After removal, ME has a very short time frame
for examining the brain before it turns to mush
After all needed samples are taken, the body is
sutured and returned to the family for burial
Determine if the bones are human
The front paw bones of a bear are very similar to the human
hand
Shell fragments from turtles can be mistaken for human
skull fragments
Sheep ribs are similar to human ribs
Infants are almost impossible to identify since the bones are
much smaller (confused with small animals) and the skull is
not yet fused so a full skull will not be found
A forensic Anthropologist uses the fact that bones have
ridges, indentions, and bumps that are indicative of
particular species and function
These traits are used to identify species
Determine Age
More accurate for younger victims than older victims
Why is this?
Look for:
Teeth – used to identify someone 18 years or younger, since all teeth
are typically in place by that age
Skull – not of any use in adults, but in infants, one can determine age
based on fusing of suture lines in the skull fragments
Legs and Arms – determine age of 25 or younger, bones have
reached max growth by that age
Pelvis – stops growing at age 50
Ribs – can determine age up to 70 years ( ±1.5 years up to 30 years
old and ±5 years up to 70 years old)
Bone Density – less dense means older person
Determine Stature
If a full skeleton is found, this job is easy. Sadly, a
full skeleton is rarely ever found
Height is usually 5 times the length of the humerus
(upper arm bone)
Thickness of bone is proportional to muscle
structure
Also can be indicative of dexterity, right handed people
have thicker bones on the right side of the body
Determine Sex –
In infants this is nearly impossible
In adults or teens, puberty has set bones into
gender specific patterns
In males, the humerus, the radius (the lower bone in the thumb),
and the femur are larger in males
The female pelvis is wider and the pelvic outlet is more open, for
childbirth purposes
The male pelvis is designed only for support and movement, thus it
is thicker and the pelvic outlet is much more narrow
The male mandible ( jaw bone) is slightly curved and in females, it is
straight
The male skull has more prominent crest and ridges and is much
thicker and larger
Determine Race
Skulls
Caucasians – have high rounded skulls, straight faces, and
narrow protruding noses, triangular eye sockets
Negroid – lower and narrower skulls, wider and flatter
noses, prominent and protruding teeth, squared eye
sockets
Mongoloids – broad round skulls, arched face, round eye
sockets, wide facial dimensions
Mixed Race – can not be determined due to mix of
features
Examine artifacts from burial site
Chemical Analysis – measure nitrogen levels in
the bones, Nitrogen decreases as time passes;
Also look for amino acids, bones that are fresh
may yield 15 aminos and old bones give off only
7 aminos
UV Light Test – fresh bones glow when exposed
to UV light, bones 100 years old or older do not
glow at all
Radioactive Dating – Not of any major use in
forensics due to gaps in accuracy
Stiffening of the muscles in the body following
this time scale:
2 hours: small muscles in the face and neck stiffen
and the progress heads to the lower body
8-12 hours: body is completely stiff and in position
at time of death unless body is altered
posthumously
30 hours: the body loosens again as blood begins to
pool, this period of stiffness is called the rigid state
The relaxed state after 30 hours is called flaccid state
A victim who ran from an assailant will show
stiffening in the legs first
Poisoned victims become stiff instantly due to
nervous system reaction to poison
Elevated body temperature prior to death
speeds up the rigor mortis process
Livor Mortis or Postmortem Hypostasis
Stagnation of the blood in the vessels due to the
stopping of blood flow and pooling where gravity
takes it
Any part of the body that presses against a firm
surface is pale and the surrounding areas are livid
Appears about 30 minutes after death and reaches
maximum at 8-12 hours after death
Color indicates condition
Red/Pink – high oxygen levels
Deep purple – severe heart failure
Gray - poison
The takeover of bacteria beginning the
decomposition process
Mummification – occurs when body dries out due
to high temperatures or concentration gradient
(Egyptians using salt)
Adipocere Formation – formation of a waxy
substance due to influx of water (grave wax), it
takes three to six months to form
When sinkers become floaters:
Rise to surface due to gas buildup from decomposition
of body tissues
In warm water the time of flotation takes much less
time than cooler water
Blowflies – show up within the first hour after
death to lay eggs in the nose, armpit, groin,
mouth, and open wounds
Within 24 hours, the eggs hatch and maggots are
present
Within three days, they are ½ inch in length
After 12 days, the maggots have fully developed
and the process continues
Generally, if only eggs are present, ME will
determine TOD to be within the last 24 hours
Exceptions:
Blowflies do not lay eggs at night and are less
abundant during winter months
This as well as maggots being dormant during cold spells
and timing being key makes TOD determination difficult
is the killer has read up on his entomology