1. Definition of Death Cessation, or end, of life
Irreversible cessation of blood circulation
Cessation of all brain activity
Experts do not agree on a single definition

2. Introduction
Autolysis —
cell death

3. The Manner of Death The manner of death can be
Natural, the most common
Accidental
Suicidal
Homicidal
Undetermined
Sometimes the manner of death is difficult to determine

4. Cause and Mechanism of Death
Cause of the death
Mechanism of death
is the reason for the death
is the specific change in the body that brought about the cessation of life

5. Time of Death—Livor Mortis
The Leaden-Color of Death
Lividity—With decomposition, blood seeps down and settles in the lower parts of a body
Red blood cells turn bluish-purple

6. Time of Death—Livor Mortis

7. Time of Death—Livor Mortis
Lividity begins about two hours after death
Discoloration becomes permanent after eight hours
Ambient temperature affects the speed of decomposition
Position can determine the lividity of the body during the first eight hours

8. Time of Death—Rigor Mortis
The Rigidity of Death
Without oxygen in the blood—
Calcium accumulates in the muscles
Muscles stiffen
Starts in the head and expands throughout
After about 15 hours—
Muscle fibers begin to dissolve
Softening begins

9. Time of Death—Rigor Mortis

10. Time of Death—Rigor Mortis
Observation
Approx. Time Scale
The body is at its most rigid state
Just over 2 hours
No visible signs of rigor
Less than 2 hours
or more than 48 hours ago
Stiffness generally disappears
After 36 hours

11. Time of Death—Rigor Mortis
Factors affecting rigor mortis:
Ambient Temperature
Cold- slows rigor
Warm- Accelerates Rigor
Clothing or Lack of Clothing
Clothes = accelerates rigor
No Clothes = slows rigor
Sun Exposure
Accelerates rigor
Activity/Exercise
Exercising or struggling = accelerates rigor
Sleep = slows rigor
Body Weight
Obese- slows rigor (fat stores oxygen)
Thin- Accelerates Rigor

12. Time of Death—Algor Mortis
The Chill of Death
Body heat falls after death
About 1.5 degrees per hour immediately after death
Slowing to less than 1.0 degree per hour after about 12 hours
Heat loss is affected by the ambient temperature
Corpse temperature is measured by a thermometer inserted into the liver
Time of death is expressed as a range of time

13. Time of Death
—Stomach and Intestinal Contents

14. Time of Death —Stomach and Intestinal Contents
State of Contents
Timing of Death
Zero to two hours after the last meal
Stomach is empty, but food found in small intestine
Death occurred 12 or more hours after a meal
Undigested food present in the stomach
Death occurred at least four to six hours after a meal
Small intestine is empty; waste found in large intestine

15. Time of Death —Stages of Decomposition
Within two days of death:
After four days:
Within six to ten days:

16. Time of Death —Stages of Decomposition
1) Within two days of death:
cell autolysis begins
green and purplish staining occurs from blood decomposition
face becomes discolored

17. Time of Death —Stages of Decomposition
2) After four days
skin blisters
abdomen swells with CO₂ that is released by bacteria in the intestines

18. Time of Death —Stages of Decomposition
3) Within six to ten days
corpse continues to bloat as bacteria continue to feed on tissues; eventually chest and abdomen will burst
fluids begin to leak from body openings
eyeballs and other tissues liquefy
skin sloughs off

19. Time of Death—Insects Forensic entomologist
Collects insect evidence from on, above, and below the body
Records environmental conditions
Within minutes of a death, certain insects arrive to lay their eggs on the warm body—blowflies
As the corpse decomposes, other kinds of insects arrive

20. Time of Death—Insects
The insect life cycle provides scientists with a benchmark to estimate a time of death
Insect evidence cannot provide an exact time of death—fluctuating environmental conditions
Insect evidence provides a close estimate

21. Time of Death —Blowfly Life Cycle
<8 hours after death—blowfly eggs can be found in the moist, warm areas of a corpse
Within 20 hours —1st of their 3 larva stages
Within 2.5 days —2nd of their 3 larva stages
4th or 5th day—3rd of their 3 larva stages

22. Time of Death —Blowfly Life Cycle
8 to 12 days—larvae migrates to a dry place
18 to 24 days— Early pupa; immobile; changes from light brown to dark brown
By the 21st-24th day the pupa cases will split open and adult blowflies will emerge.

23. Time of Death —Blowfly Life Cycle

24. Time of Death —Blowfly Life Cycle

25. Time of Death —Blowfly Life Cycle

26. Time of Death —Blowfly Life Cycle

27. Time of Death —Blowfly Life Cycle

28. Acknowledgements
Adapted and modified from Bertino and Bertino, Forensic Science: Fundamentals and Investigations.