DEATH
Bodies, Bugs & Bones
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
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
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)
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 Metamorphosis
Blow flies are attracted to dead bodies and often arrive within minutes of the death of
an animal. They have a complete life cycle that consists of egg, larva, pupa, and
adult stages.
1st – Adult flies lay eggs on the carcass especially at
wound areas or around the openings in the body such
as the nose, eyes, ears, anus, etc.
Adult
Pupa
Eggs
2nd – Eggs hatch into larva (maggots) in 12-24 hours.
3rd– Larvae continue to grow and molt (shed their
exoskeletons) as they pass through the various instar
stages.
1st Instar - 5 mm long after 1.8 days
2nd Instar - 10 mm long after 2.5 days
3rd Instar – 14-16 mm long after 4-5 days
3rd Instar
Larva
2nd Instar
Larva
4th – The larvae (17 mm) develop into pupa after
burrowing in surrounding soil.
5th – Adult flies emerge from pupa cases after 6-8
days.
1st
Instar
Larva
It takes approximately 14-16 days from egg to
adult depending on the temperatures and
humidity levels at the location of the body.
Image: http://www.umext.maine.edu/images/FlyLife.jpg
Information: http://www.kathyreichs.com/entomology.htm and http://www.forensicentomologist.org/
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
Examples of Diptera (Flies)
Early Stage
Decomposition
Blow &
Greenbottle Flies
(Calliphoridae)
Flesh Fly
(Sarcophagidae)
Striped thorax
Metallic thorax and abdomen
Life Cycle of a
Calliphoridae Fly
Late Stage
Decomposition
House Fly
(Muscidae)
Cheese Skipper
(Piophilidae)
Informational Source: http://naturalsciences.org/files/documents/csi_tg_overview.doc
Images: Top Left - http://www.scienceinschool.org/repository/images/issue2forensic3_large.jpg, Middle-Left: http://forensicfact.files.wordpress.com/2008/04/blowfly053.jpg,
Top Right - http://users.usachoice.net/~swb/forensics/P1.jpg, Bottom - http://www.deathonline.net/decomposition/corpse_fauna/flies/index.htm
Examples of Coleoptera (Beetles)
Early Stage Decomposition
Early to Late Stage Decomposition
Carrion Beetles (Silphidae)
Rove
Beetles
Clown
Beetles
(Staphylinidae)
(Histeridae)
Adults & larvae feed on fly larvae
Predator of fly eggs
Late Stage Decomposition
Ham & Checkered
Beetles (Cleridae)
Predator of flies & beetles;
also feed on dead tissue
Predator of fly eggs
Hide Beetles
Skin Beetles
(Scarabidae)
Usually the last to arrive
(Dermestidae)
Feed on dried skin & tissues
Informational Source: http://naturalsciences.org/files/documents/csi_tg_overview.doc
Images: http://www.cals.ncsu.edu/course/ent425/library/spotid/coleoptera/coleoptera.html & http://www.forensicflies.com/beetles.htm
Chart - http://www.clt.uwa.edu.au/__data/page/112507/fse07_forensic_entomology.pdf
Weather data is also an important tool in analyzing insect evidence from a corpse.
Investigators will make note of the temperature of the air, ground surface, the
interface area between the body and the ground, and the soil under the body as
well as the temperature inside any maggot masses. They will also collect weather
data related to daily temperature (highs/lows) and precipitation for a period of
time before the body was discovered to the time the insect evidence was collected.
Other factors that might affect their PMI estimates:
1.
Was the body enclosed in an area or wrapped in a material that would have
prevented flies from finding the corpse and laying eggs?
2.
Were other insect species present that may have affected the development of the
collected species?
3.
Were there drugs or other poisons in or on the body that might have affected the
larvae’s development?
Did you know…
The “Body Farm” in Knoxville, Tennessee is a university research
facility to investigate human decomposition under various conditions
in order to understand the factors which affect its rate.
Click the image to view a video
about the Body Farm!
Let’s give it a try …
Click the image above or click here to visit the website at
http://www.pbs.org/wnet/nature/episodes/crime-scene-creatures/interactive-determine-the-time-of-death/4390/