1. The Process of
death
Chapter 13
Forensic Science
Mrs. Morgan

2. Confirming Death
• Although it may be obvious,
any death must be confirmed
by a trained professional –
usually a doctor, coroner or
medical examiner
• Must meet the criteria of death
– then pronounced dead
• Body can then be moved,
handled and processed if
necessary

3. At the crime scene
• A dead body found at a crime
scene is handled and processed
by the medical examiner’s office
• Officers and CSIs cannot touch
or move the body until the ME
has given permission to do so
• Any evidence on a body is
collected by the ME staff and
turned over to the crime lab

4. Time of Death
Algor Mortis: Body cooling
rate
• The body slowly cools once the
heart stops beating
• Measuring body temperature can
approximate the time of death
• Use liver temperature
• Can be influenced by the
environment or internal
conditions

5. Click to Time of Death
edit Master title style
• Calculating time of death – Glaister Equation
Hours since death = 98.4°F – internal body temperature
1.5
• Used as a starting point to determine time of
death – ultimately use other factors to
corroborate a more accurate time

6. Changes to the body
Livor Mortis: skin discoloration
caused by the pooling of blood
• When heart stops beating,
blood pools and coagulates
in lower portions of the body
due to gravity – creates
red/purple blotches
• Can show the position of
body after death
• May indicate if the body has
been moved or repositioned

7. Post-Mortem Lividity
•Starts 30 min – 3 hours after death
•Maximum lividity 6 – 12 hours after death
Parts of body touching the
ground/surface show no lividity
due to compressed capillaries

8. More changes
Rigor Mortis: rigidity of skeletal
muscles
In humans:
•starts after about 3 hours
•reaches maximum stiffness
after 12 hours
•gradually dissipates until
approximately 72 hours
after death. I don’t know – I googled
“rigor mortis” and this
was one of the top hits…

9. Overall timetime death
Overall of of death
• Pathologists will use multiple factors to
calculate TOD
• Always a small margin of error
Temperature of
Stiffness of body Time since death
body
Warm Not stiff Not dead more than 3 hours
Warm Stiff Dead between 3 and 8 hours
Cold Stiff Dead between 8 and 36 hours
Cold Not stiff Dead for more than 36 hours

10. Stages of Decomposition
Initial or fresh decay
(autolysis): The cadaver appears
fresh but is decomposing internally
due to the activities of bacteria
present before death (0-4 days).
Putrefaction or bloating: The
cadaver is swollen by gas produced
internally, accompanied by the
odor of decaying flesh (4–10 days).

11. Stages of
Decomposition
Black putrefaction: Flesh of
creamy consistency, with exposed
body parts black. Body collapses as
gases escape. Fluids drain. Odor of
decay very strong (10–20 days).
Butyric fermentation: Cadaver
drying out. Some flesh remains at
first; cheesy odor from butyric acid
(20–50 days).

12. Stages of Decomposition
Dry decay (diagenesis):
Cadaver almost dry; slow rate of
decay. May mummify (50–365
days).
All of the changes that accompany
decomposition are subject to
variation based on individual
characteristics and the environment

13. The autopsy
• Performed to determine
cause and manner of death,
discover the extent of disease
or for teaching purposes
• Forensic autopsies have legal
implications
• Performed by a pathologist –
specially trained MD

14. Who & why
• ME can order an autopsy
• If not – need permission from next
of kin
• Autopsied people include
– Suspicious deaths
– Not under the care of a doctor
– Died during an operation
• Family can limit scope or request
specific procedures be followed

15. The tools
Stryker saw – used to cut
through the skull to
remove the brain
Standard tools used in
an autopsy

16. Autopsies – the outside
• Starts with thorough external
exam
– Physical attributes
– Scars and/or tattoos
– Evidence of wounds/bruises
– All findings diagramed and
recorded in detail

17. Autopsies – the inside
• Body is open with a Y-incision
to expose the thoracic and
abdominal cavities
– Shoulders to pubic bone
• Ribs are cut to expose the heart
and lungs
• Organs are removed, weighed
and examined

18. Finishing up
Tissue and fluid samples are
taken, analyzed and stored
Organs returned to proper
place in cavities and
incisions are sewn up