Death: Meaning, Manner,
Mechanism, Cause, Time
Chapter 11
Back in the day …
17th century: anyone in a coma or with a
weak heartbeat was presumed dead &
buried
fear of being buried alive = cowbell in
coffin (“saved by the bell”?)
“waiting mortuaries”
Death is …
… cessation (end) of life?
… “irreversible cessation of blood
circulation”?
… cessation of all brain activity?
hard to give a single definition of – it is a
PROCESS rather than an instant event
1st stage of death: STOPPAGE
heart stops  cells begin to die (no O2) 
body processes fail (no O2)  nerves,
muscles, organs, brain fail
autolysis:
cell breakdown
Manner of Death (MOD)
natural death (most common)
- interruption/failure of body
functions from age or disease
accidental death
- unplanned events (car
accident, falling from a ladder)
suicidal death
- person purposefully kills
oneself
homicidal death
- death of one person caused
by another
undetermined
What’s the MOD?
A man with a heart
condition is attacked and
dies from a heart attack
during the assault. Is the
MOD accidental or
homicide?
An elderly woman dies
after being kept from
receiving proper health
care by her son. Is the
manner of death natural or
homicide?
Cause of Death (COD)
the reason someone dies is the COD
disease, physical injury, stroke, heart
attack, bludgeoning, shooting, burning,
drowning, strangulation,
hanging, suffocation, etc.
“proximate cause of death”
is an underlying cause (as
opposed to the final cause)
Mechanism of Death
the specific body change that brought
about cessation of life
ex: if COD is shooting,
mechanism may be blood
loss (exsanguination) or
loss of brain function
ex: if COD is a heart
attack, mechanism may
be heart stopping to
beat or pulmonary arrest
Time of Death (TOD)
many factors are used to estimate TOD
Livor Mortis
literally means DEATH COLOR
RBC break down & spill contents
hemoglobin turns
purple when it spills
purplish color visible
wherever blood pools
(lividity)
Livor
Mortis
2 hrs after death: lividity begins
8 hrs after death: discoloration permanent
between 2 and 8 hrs after death: if you press
skin, discoloration disappears
ambient temp affects time for lividity to set in
(hotter = faster)
can reveal approximate TOD and position of
corpse and if they’ve been moved (dual lividity)
Rigor Mortis
literally means DEATH STIFFNESS
temporary
Rigor Mortis
no visible rigor:
<2 hrs or >48 hrs
very rigid (full rigor):
~12 hrs
rigor only in face & neck:
just over 2 hrs
some rigor in body, none in face:
more than 15 hrs ago
Rigor Mortis
stiffness occurs
because skeletal
muscles can’t
relax (they are
contracted) due
to presence of
extra calcium
muscles control
bone movement
so joints appear
to be rigid too
Rigor Mortis
Rigor Mortis
factors that affect rigor mortis include:
- ambient temp (warmer = faster due to
faster chem reactions)
- body weight (thinner = faster due to less
stored O2)
- type of clothing (clothed = faster)
- illness (sick/fever = faster)
- level of activity before death (aerobic
exercise = faster)
- sun exposure (sunlight = faster)
Rigor Mortis
Algor Mortis
literally means DEATH HEAT
temperature loss
generally,
- lose 1.4oF per hour
for the first 12 hrs
- lose 0.7oF per hour
after 12 hrs until
body reaches temp
of surroundings
Stomach & Intestinal Contents
also used to help
determine TOD
4-6 hrs for stomach
to empty contents
into small intestine
another 12 hrs for
food to leave small
intestine
24 hrs for all
undigested food to
be released
Stages of Decomposition
 within 2 days
- cell autolysis
- green/purplish staining
- marbled skin
- discolored face
 after 4 days
- skin blisters
- abdomen swells with CO2
 within 6 to 10 days
- corpse bloats with CO2
- chest/abdominal cavities burst and collapse
- fluids leak from body openings
- eyeballs/other tissues liquefy
- skin sloughs off
Forensic Entomology
Flies arrive within 10 minutes of death
Type of insects follows a succession as the
body undergoes changes fromThe fresh stage, to the bloating stage to
the dry or skeletal stage when the skin
falls of leaving teeth and bone
Four development stages of flies:
egg
Hatch into a larva or maggot
crawls like a caterpillar and actively
consumes food to grow quickly.
Maggots will pass through several
instars or stages – keep getting bigger
and molt at end of every stage
Next stage: a dark immobile pupa.
adult fly emerges from pupa
Adults mate, and the females will lay
more eggs onto corpses.
Lays eggs in natural body openings
Eggs/ worms in head area first
Then reproductive/ excretory regions
Trunk at very late stage
Insects are ectothermic-body needs to be
warmed by outside to be able to grow
Will speed up process in hot climates/slow
in cold regions
Drugs – cocaine will speed up life cycle
Drugs – poisons (arsenic) will slow down
Order of flies
Blow flies and flesh flies – arrives in 10
minutes
Blow flies will lay eggs on corpse on day 1
Will see maggots by day 2
Blow fly maggot
Flesh flies will deposit maggots on corpse
on day 1
Day 1-3 protein and carbs
House flies come after the flesh fly and
blow fly
Will lay eggs by day 2 and maggots will be
seen by day 4
The next fly to follow ONLY IN URBAN
areas is the skipper fly
Will lay eggs by day 5; maggot by day 7
Predatory flies appear next to feed on the
flies , NOT ON THE CORPSE
These are beetles, wasps etc
Fresh stage
0-3 days Protein, carbs break down
- Blows flies and flesh flies
- no smell yet
Bloated stage3-7 days Decay starts- smell startsabdomen bloats due to CO2 made by
bacterial respiration
House flies and predatory flies
Decay stage (putrid smell due to gas
release)
8-18 days – total decay- all body bloats;
abdomen breaks down – fluid seepage
Ants, cockroaches, beetles
Over 18 days – drying out phase; flesh
falls off; worms not present
Mainly bugs that can feed from bones
such as beetles.
Bugs seen at end stage