1. Death: Meaning, Manner, Mechanism, Cause and Time

2. “ SAVED BY THE BELL”

3. WHAT IS DEATH?
Is a person with a heartbeat alive even if there is no brain activity?
Death is a process not an event
Physiologists; when the heart stops beating, the cells begin to die
O2 levels drop
Basic processes of the body fails
Nerves, muscles, organs stop working, Stoppage
Once enough cellular death occurs life cannot restart

4. Death Manner of Death, Cause of death: The reason someone dies
Natural, Accidental, Suicidal, Homicidal, Undetermined
Cause of death: The reason someone dies
Disease: physical injury, stroke, heart attack
bludgeoning, shooting, hanging suffocation,
Mechanism of Death: the specific change in the body that brought about the cessation of life
exsanguinations (Blood loss)
Pulmonary arrest (Heart stoppage)
Unnatural Deaths – Accident, Execution, Homicide, Misadventure, Being attacked by insects, reptiles, fishes, lions, tigers, bears, stingrays, or other wild animals, Adverse outcome of surgery, Suicide, Terrorism, War 4 4

5. 9 Ways to determine time of death!
Rigor mortis
Livor mortis: (Lividity)
Algor mortis: Body Core Temperature
Potassium levels in vitreous humor + Clouding of the cornea
Stomach Contents
Evidence of Decompositional Process
Presence/absence of purge fluids
Drying of the tissue
Insect Larval Instars

6. LIVOR MORTIS Means: bluish color As the body begins to decompose,
Blood seeps down through the
Tissues and settles into the lower parts of
The body. The RED BLOOD CELLS begin the breakdown,
Spilling their contents, BLOOD turns purple when it spills
out of the cells. The purplish color is visible on parts of the skin
Wherever blood POOLS.

7. Determine Time of Death —Livor Mortis
Process when body decomposes and blood seeps down and settles into lower parts of body.
Lividity :
pooling or settling of blood in tissues after death.
Begins 2 hours after death becomes permanent after 8.
Livor mortis results in the settling of blood in areas of the body closest to the ground (begins immediately on death and continues up to 12 hours). 7

8. Determine Time of Death —Livor Mortis
Livor mortis can:
Determine Time of Death
Within 2-8 hours, can press skin and color disappears
Factors affecting lividity
Ambient temperature, anything that could impede flow of blood to area
Reveal the position of the corpse within first 8 hours
If on back, blood will pool along backside
Reveal if the body was moved
If moved, may show dual lividity from first position and then from second position 8

9. * Is a settling of the blood in the lower portion of the body
** Causing a purplish red discoloration of the skin.
*** Discoloration does not occur in the areas of the body that are in contact with the ground or another object, due to compressing of the capillaries

10. RIGOR MORTIS- (L: rig- stiff; mortis) —death
Factors that affect rigor mortis
Ambient temperature,
Cooler the body the slower to onset of rigor
Person’s weight
fat stores more oxygen and slow rigor
Type of clothing
Helps keep the body warm
Illness
Dies with a fever? What would you expect?
Hypothermic? What would you expect?
Level of physical activity
Struggling before death rigor, What would you expect?
Sun exposure,
Sun tanner? What would you expect?
Illness – hyperthermia will slow rigor or a fever means high temps and fast rigor 10 10

11. Stiffening of the skeletal muscles after death
RIGOR MORTIS-
Stiffening of the skeletal muscles after death
At death, skeletal muscles cannot relax.
Without oxygen, calcium accumulates in these muscles.
Calcium is used by the body to signal muscle contraction, this accumulation signals the muscles to contract.
The muscles become stiff.
Rigor mortis starts in the head and works its way down to the legs. 11 11

12. Time
Event
Appearance/
Circumstances
2-6 hours
Rigor begins
eyelids, Jaws stiffen after 2 hours, then center of body stiffens, then arms & legs
12 hours
Complete Rigor
Entire body rigid

13. 15-36
Slow loss of rigor, small muscles first
Lost in head and neck, last in bigger leg muscles
36-48
Rigor disappears, muscles become relaxed
Many variables may extend rigor beyond the normal 36 hours

14. Cooling of the body after death
Determine Time of Death —Algor Mortis
Cooling of the body after
death
In death a body no longer generates warmth and begins to cool down.
To find the standard temperature of a corpse, a thermometer is inserted into the liver.
Time of death determined by temperature calculations is expressed as a range of time.
Normal body temperature is 98.6°F (37°C)
Celcius to Farhenheit conversion = (C x 9/5) + 32 = F
Farhenheit to Celcius conversion = (F -32) x 5/9 = F 14 14

15. Determine Time of Death —Algor Mortis
Calculations
First 12 hours after death:
Body cools 0.78 °C (1.4 °F) per hour
After 12 hours after death:
Body cools 0.39 °C (0.7 °F) per hour
Example
What is the temperature loss for someone who has been dead for 12 hours?
0.78 ° C x 12 hours = 9.36 ° C 15 15

16. Questions: What are some Factors that would affect Algor Mortis?
Ambient temperature
Wind?
Excess body fat?
Clothing
etc

18. 24 hours for the food to leave the large intestine
Determ for ine Time of Death
—Stomach and Intestinal Contents
4-6 hours stomach to empty contents into small intestine
Another 12 hours for the food to leave the small intestine for the large intestine
24 hours for the food to leave the large intestine
If undigested stomach contents are present, then death occurred zero to two hours after the last meal.
If the small intestine is empty and wastes are found in the large intestine, then death occurred 12 or more hours after a meal. 18 18

19. Determine Time of Death —Stomach and Intestinal Contents
Example –
Determine the time of death from the last meal if food is found in the small intestine
Answer: Death occurred hours after the last meal 19 19

20. Determine Time of Death —Stages of Decomposition
Within 2 days
Cell autolysis begins following death.
Green and purplish staining from blood decomposition.
Marbling appearance on the skin. Discoloration of the face.
After 4 days
The skin blisters.
The abdomen swells.
Within 6-10 days.
The corpse bloats.
Fluids begin to leak from body openings as cell membranes rupture.
The skin sloughs off.
Eyeballs and other tissues liquefy.
Potassium level in ocular fluid – cells within inner surface of eyeball release potassium
Rigor mortis – the muscles relax and then become rigid without shortening of the muscle
Livor mortis – when human heart stops pumping, the blood begins to settle in the parts of the body closest to the ground. The skin will appear as a dark blue or purple color in these areas. The skin will not appear discolored in areas where the body is restricted by either clothing or an object pressing against the body. Info useful in determining if the victim’s position was changed after death. 20 20

21. 6. Entomology

23. Blow Fly Life cycle

24. Forensic Entomology
Within minutes of a death, certain insects arrive to lay their eggs on the warm body.
Blowflies are a common example.
As a corpse progresses through the stages of decomposition, other kinds of insects arrive. 24 24

26. Entomology Flies

27. Total Time 16 – 35

29. The American carrion beetle, Necrophila americana. 
Although this beetle is primarily nocturnal,
it is commonly observed on the upper surfaces of a body during the daylight hours. 
Large aggregations of these beetles have been observed, and they can sometimes be as numerous as flies.  
Entomology Beetles
The sexton beetle, Nicrophorus orbicollis.  The sexton beetles are generally nocturnal and
are typically found under a body or in the soil immediately surrounding the remains during the daylight hours.