1. STAGES OF DECOMPOSITION
WARNING…. GRAPHIC MATERIAL
STAGES OF DECOMPOSITION
Mrs. MacWilliams
CSI Forensic Science

2. DEATH Two types of death: somatic and cellular.
Somatic death occurs when the individual is irreversibly unconscious- what we consider “dead.”
This does not mean all functions immediately cease.
After somatic death, the body’s cellular processes continue.
Time frame for this continuance varies according to many things like:
type of cell (blood, tissue, organ, etc)
trauma to the cells (like a stab wound or drowning)
activity level before death
environmental factors (like rain or temperature).
These factors affect when algor mortis, rigor mortis, and livor mortis occurs and when the body begins to decay.

3. Algor mortis Algor mortis = cooling of body temperature after death.
Begins immediately after death  metabolism in body tissues stops
Measuring internal body temperature for indication of time of death
NEWTON’s Law of Cooling = rate of change of the temperature of an object is proportional to the difference between its own temperature and the ambient temperature.
Hours since death = (98.4°F – internal body temperature) ÷ 1.5

4. RIGOR MORTIS
Stiffening of the muscles due to lactic acid build up after somatic death
Muscle cells are still alive, contract, produce stiffening effect
Rigor mortis usually occurs about 2-3 hours after death
Around 36 hours after the onset of rigor mortis, the body again relaxes and is pliable

5. LIVOR MORTIS
Pooling of blood in the body due to gravity after heart stops
Appears on skin as purplish-red discoloration
Can give indication of body position at time of death
Does not happen in areas that are in contact with the ground or other objects
Begins within ½ hour after death and most evident in first 12 hours
Will not move regardless of how body is disturbed

6. THE LIVING PIG A live pig is not outwardly decomposing
intestines contains bacteria, protozoans, and nematodes
Some of these micro-organism are ready for a new life, should the pig die and lose its ability to keep them under control.

7. THE 5 STAGES OF DECAY
Five stages of decay  each stage attracts its own set of insects
Succession is what aides the forensic entomologist in determining the time of death
AKA Post Mortem Interval or PMI

8. Stage 1: Initial Decay 0-3 days after death
State of decay
After death, bacteria in intestine begin to digest the intestine itself, break out of the intestine and digest surrounding internal organs
Body's own digestive enzymes spread through the body, contributing to its decomposition
Enzymes inside cells are released and break down the cell and its connections with other cells
AKA“Fresh Stage”

9. Stage 1: Initial Decay 0-3 days after death
Insect activity
Flies are attracted to bodies.
Blowflies and house flies are able to lay eggs around wounds and natural body openings (mouth, nose, eyes, anus, genitalia)
Eggs hatch and move into the body, often within 24 hours.
Life cycle of a fly from egg to maggot to fly takes from two to three weeks  longer at lower temperatures

10. Stage 2: Putrefaction - 4 to 10 days after death
State of decay
Bacteria break down tissues and cells, releasing fluids into body cavities
produce various foul smelling gases that are very attractive to a variety of insects
Build up of gas, creates pressure within the body and inflates the body, forcing fluids out of cells and blood vessels, into the body cavity
AKA
“BLOAT STAGE”

11. Stage 2: Putrefaction - 4 to 10 days after death
Insect activity
maggots move throughout the body, spreading bacteria, secreting digestive enzymes and tearing tissues with their mouth hooks
Move as a maggot mass benefiting from communal heat and shared digestive secretions
Smells and body fluids begin to attract more blowflies, flesh flies, beetles and mites
Later-arriving flies and beetles are predators, feeding on maggots as well as the decaying flesh
Parasitoid wasps lay their eggs inside maggots and pupae.

12. Stage 3: Black putrefaction - 10 to 20 days after death
State of decay
Bloated body eventually collapses, becomes flat
Exposed parts are black in color and have very strong smell of decay
Large volume of body fluids drain from the body at this stage  seep into the surrounding soil
Other insects and mites feed on this material
Insects consume bulk of flesh
body temperature increases with their activity
Bacterial decay is still very important
will eventually consume the body if insects are excluded

13. Stage 3: Black putrefaction - 10 to 20 days after death
Insect activity
Several generations of maggots are present on the body and some have become fully grown.
Migrate from the body and bury themselves in the soil where they become pupae
Predatory maggots are much more abundant and flies cease to be attracted to the corpse
Predatory beetles lay their eggs in the corpse and their larvae hatch out and feed on the decaying flesh
Parasitoid wasps laying their eggs inside maggots and pupae

14. Stage 4: Butyric fermentation - 20 to 50 days after death
State of decay
Remaining flesh is removed over this period and the body dries out
cheesy smell caused by butyric acid
smell attracts a new suite of corpse organisms
surface of the body in contact with ground becomes covered with mold as the body ferments

15. Stage 4: Butyric fermentation - 20 to 50 days after death
Insect activity
Beetles feed on the skin and ligaments.
Beetle larvae hatch from eggs which fed on the body in earlier stages of decay
Cheese fly consumes any remaining moist flesh at this stage, even though it is uncommon earlier in decay
Predators and parasitoids are still present at this stage including numerous wasps and beetle larvae

16. Stage 5: Dry decay - 50-365 days after death
State of decay Body is now dry and decays very slowly
Eventually all the hair disappears leaving only the bones

17. Decompostion of a Baby Pig
Pictures from
Just for fun… MAGGOT CHEESE!!! Would you eat this??? Maggot cheese video