DEATH Bodies, Bugs & Bones. Back in the day … 17 th century: anyone in a coma or with a weak heartbeat was presumed dead & buried fear of being.

DEATHBodies, 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 CODdisease, 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 Deaththe specific body change that brought

about cessation of lifeex: 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 COLORRBC break down & spill contentshemoglobin turns

purple when it spillspurplish color visible

wherever blood pools (lividity)

Livor Mortis

2 hrs after death: lividity begins8 hrs after death: discoloration permanentbetween 2 and 8 hrs after death: if you press

skin, discoloration disappearsambient 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 Mortisliterally means DEATH STIFFNESStemporary

Rigor Mortisno visible rigor:

<2 hrs or >48 hrsvery rigid (full rigor):

~12 hrsrigor only in face & neck:

just over 2 hrssome rigor in body, none in face:

more than 15 hrs ago

Rigor Mortisstiffness 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 Mortisfactors 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 Mortisliterally means DEATH HEATtemperature lossgenerally,

- lose 1.4oF per hourfor the first 12 hrs- lose 0.7oF per hourafter 12 hrs untilbody reaches tempof 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 Decompositionwithin 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 EntomologyFlies arrive within 10 minutes of deathType 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 maggotcrawls 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 pupaAdults mate, and the females will

lay more eggs onto corpses. Lays eggs in natural body openings Eggs/ worms in head area firstThen reproductive/ excretory regionsTrunk 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 cycleDrugs – poisons (arsenic) will slow

down

Order of fliesBlow flies and flesh flies – arrives in 10

minutesBlow flies will lay eggs on corpse on

day 1Will see maggots by day 2

Image: http://www.umext.maine.edu/images/FlyLife.jpgInformation: http://www.kathyreichs.com/entomology.htm and http://www.forensicentomologist.org/

Blow Fly Metamorphosis

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.

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

4th – The larvae (17 mm) develop into pupa after burrowing in surrounding soil.

5th – Adult flies emerge from pupa cases after 6-8 days.

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.

It takes approximately 14-16 days from egg to adult depending on the temperatures and humidity levels at the location of the body.

Adult

EggsPupa

3rd Instar Larva

2nd Instar Larva

1st Instar Larva

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 stage0-3 days Protein, carbs break down- Blows flies and flesh flies- no smell yetBloated stage- 3-7 days Decay starts- smell starts-

abdomen 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, beetlesOver 18 days – drying out phase; flesh

falls off; worms not presentMainly bugs that can feed from bones

such as beetles.

Bugs seen at end stage

Examples of Diptera (Flies)

Informational Source: http://naturalsciences.org/files/documents/csi_tg_overview.docImages: 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

Flesh Fly(Sarcophagidae)

Striped thorax

Blow & Greenbottle Flies(Calliphoridae)

Metallic thorax and abdomen

House Fly(Muscidae)

Cheese Skipper (Piophilidae)

Early Stage Decomposition

Late Stage Decomposition

Life Cycle of a Calliphoridae Fly

Examples of Coleoptera (Beetles)

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

Carrion Beetles (Silphidae)Adults & larvae feed on fly larvae

Early to Late Stage Decomposition

Late Stage Decomposition

Rove Beetles

(Staphylinidae)Predator of fly eggs

Early Stage Decomposition

Hide Beetles (Scarabidae)

Usually the last to arrive

Clown Beetles (Histeridae)

Predator of fly eggs

Ham & Checkered Beetles (Cleridae)

Predator of flies & beetles; also feed on dead tissue

Skin Beetles (Dermestidae)

Feed on dried skin & tissues

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!

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/

Let’s give it a try …