1. Death: Meaning, Manner, Mechanism, Cause & Time
Chapter 11

2. Death The cessation, or end, of a life.
The irreversible cessation to the circulation of blood
The heart stops beating & cannot be restored
Can also be the cessation of all brain activity

3. When the heart stops, oxygen is not carried to cells in the body & they start to die.
As oxygen levels drop, body processes fail to occur – nerves, muscles, organs, & the brain stop working.
Autolysis – when cells begin to break down, life cannot be restarted.

4. The Manner of Death 4 ways a person can die – the manner of death
Natural death
Accidental death
Suicidal death
Homicidal death
Undetermined (a possible 5 manner) is occasionally recorded on a death certificate

5. Manner of Death- Natural Death
Caused by the interruption and failure of body functions resulting from age or disease – Most Common manner
Cancer
Stroke
Heart Attack
Illness
Old Age

6. Manner of Death- Accidental Death & Suicide
Accidental Death - caused by unplanned events, such as a car accident or falling from a ladder.
Suicide – a person purposefully kills oneself, whether by hanging, drug overdose, gunshot, or some other method

7. Manner of Death - Homicide
Death of one person caused by another person
Sometimes it is hard to determine the manner of death.

8. How would you categorize each situation below?
A man with a heart condition is attacked and dies from a heart attack during the assault? Is this manner of death accidental or homicide?
An elderly woman dies after being kept from receiving the proper health care by her son? Is her manner of death natural or homicide?

9. In both cases – the manner of death is. . .
HOMICIDE.

10. Cause and Mechanism of Death
Cause of death – the reason someone dies
Injury
Stroke
Shooting
Bludgeoning
Suffocation
“proximate cause of death” – underlying cause of death, not the final cause.
Someone exposed to large doses of radiation & then develops cancer
Mechanism of death – the specific change in the body that brought about the cessation of life.
Loss of blood (exsanguination)
Heart stopping (pulmonary arrest)
Examples
Examples

11. Time of Death Determined during an autopsy
Many factors are used to approximate the time of death
Livor mortis
Rigor mortis
Algor mortis
Stomach & intestinal contents
Changes in the eye
Stages of decomposition
Insect activity

12. Livor Mortis Death color (rough definition)
As a body begins to decompose, blood seeps down through the tissues and settles into the lower parts of the body (LIVIDITY).
Red blood cells begin to break down & spill their contents, hemoglobin turns purple when it spills out of the cells
The purplish color is visible on the skin wherever blood pools.
This process takes time & gives a clue as to how long the person has been dead.

13. Livor Mortis Lividity begins 2 hours after death
Discoloration is permanent after 8 hours
If death occurred between 2 – 8 hours, lividity will be present but if the skin is pressed, it will disappear.
The ambient temperature (temperature around the body) impacts the time it takes for lividity to occur.
The cooler the room, the longer it takes for lividity to occur.

14. Livor Mortis Can give other clues to the death of the person
It can reveal the position of the corpse during the 1st 8 hours
It can reveal if a body was moved.

15. Rigor Mortis Death stiffness (rough definition)
It is temporary and can be used to determine time of death.
Starts within 2 hours of death, starts in the head and works its way down the legs
After 12 hours, the body is at its stiffest
After 36 hours, the stiffness gradually wears away, although depending on body weight & temperature can, it can last 48 hours.

16. Rigor Mortis
Occurs because the skeletal muscles are unable to relax & remain contracted and hard due to extra calcium in the muscles that blood flow usually removed

17. Rigor Mortis Many factors impact when rigor mortis sets in
Ambient temperature – the cooler the body, the slower the onset of rigor
Person’s weight – more body a person has, the longer it takes for rigor to set in because fat holds oxygen which slows down the rigor process
Type of clothing – presence of clothes accelerates rigor because it holds heat in
Illness – if a person has a fever when they dies, rigor will set in faster
Level of physical activity shortly before death – rigor occurs more quickly when the person has been physically active right before death
Sun exposure – direct sunlight warms the body, which accelerates rigor.

18. A summary of Rigor Mortis
Time After Death
Event
Appearance
Circumstances
2 – 6 hours
Rigor begins
Body becomes stiff & stiffness moves down the body
Stiffness begins with the eyelids & jaw muscles after 2 hours, then center of body stiffens, then arms & legs
12 hours
Rigor complete
Peak rigor is exhibited
Entire body is rigid
15 – 26 hours
Slow loss of rigor
Loss of rigor in small muscles 1st followed by larger muscles
Rigor is lost 1st in the head & neck and last in the bigger leg muscles
36 – 48 hours
Rigor totally disappears
Muscles becomes relaxed
Many variables may extend rigor beyond the normal 36 hours

19. Factors Affecting Rigor Mortis
Event
Effect
Circumstances
Temperature
Cold temperature
Inhibits rigor
Slower onset & slower progression of rigor
Warm temperature
Accelerates rigor
Faster onset & faster progression of rigor
Activity before death
Aerobic exercise
Lack of oxygen to muscle, build up of lactic acid, & higher body temperature accelerate rigor
Sleep
Slows rigor
Muscles fully oxygenated will exhibit rigor more slowly.
Body weight
Obese
Fat stores oxygen
Thin
Body loses oxygen quickly & body heats faster

20. Algor Mortis Temperature loss of a corpse
Measured by taking the temperature of the deceased’s liver
How long it takes for a body to lose heat can help determine the time of death
At 1 hour after death, a body cools at a rate of 0.78°C (1.4°F) per hour.
After the first 12 hours, the body loses about 0.39°C (0.7°F) per hour until the body is the same temperature as the surrounding

21. Stomach and Intestinal Contents
In general, it takes 6 hours for the stomach to empty its contents into the small intestine and another 12 hours for the food to leave the small intestine
It takes approximately 24 hours from when a meal was eaten until all the undigested food is released from the large intestine.

22. Changes of the Eye Following Death
Following death, the surface of the eye dries out
A thin film is observed within 2 – 3 hours if the eyes were open at death and 24 hours if they were covered.
Following death potassium builds up in the vitreous humor inside the eye. The amount of potassium can estimate the time of death.

23. Stages of Decomposition
1. Within 2 days after death – initial decay
Cell-autolysis begins following death
Green & purplish staining occurs from blood decomposition
Skin takes on a marbles appearance
The face becomes discolored
Bacteria, protozoans, & nematodes already present in the body start to break down the body
2. After 4 days
The skin blisters
The abdomen swells with carbon dioxide gas that is released by bacteria living in the intestines – called putrefaction

24. Stages of Decomposition
3. Within 6 – 10 days
The corpse bloats with carbon dioxide as bacteria continue to feed on tissues. Eventually the gas causes the chest & abdominal cavities to burst & collapse.
Fluids begin to leak from the body openings as cell membranes rupture
Eyeballs and other tissues liquefy
The skin sloughs off
Black putrefaction – a misnomer, characteristic discoloration of the flesh (Can be blue, green, purple, brown, or black)
4. This leads to decomposition- the rotting of all tissues and organs. Bodies decompose fastest in the °C ( °F) range.
Butyric fermentation – tissues & organs have become fluid which escapes by any means and the body begins to die out. Mold usually covers some or all of the exterior of the body, a different odor emerges, not knock you over gagging as before bit it’s noticeable.
Dry decay – not mummification, but a slow process of continuous decay where tissues continue to rot, dry out and shrink until the body is skeletonized.

25. Stages of Decomposition
What Happens During Decomposition
Initial Decay
Corpse appears normal on the outside but is starting to decompose from the actions of bacteria & autolysis
Putrefaction
Odor of decaying flesh is present & corpse appears swollen
Black putrefaction
Very strong odor. Parts of the flesh appear black. Gases escape & the corpse collapses
Butyric fermentation
Corpse is beginning to dry out. Most of the flesh is gone
Dry decay
Corpse is almost dry. Further decay is very slow from lack of moisture

26. Insects
Forensic entomology- study and practice of insect observation after death
Within minutes of death, blowflies come to a corpse, attracted by the 1st stages of decomposition and lay eggs. The eggs hatch & feed on the decaying flesh.
Tiny wasps then come in and lay their eggs on maggots already present on the body.
Wasp larvae live as parasites in the maggots, feeing on their flesh
Cheese skippers arrive after putrefaction is underway, attracted by fluid seepage from the body
Last group to arrive, mites & beetles, feed on dry tissue at the end of decomposition
See blowfly chart on p.319

27. Other Bug Notes
An entomologist must be familiar with the insects of the region where a body was found or where death occurred – not necessarily the same place.
Photographs should include adult insects of all species in the vicinity, evidence of insect activity in any standing blood, & the remains of insect activity.
Body parts showing insect infestation need to be photographed before the body is removed.

28. Air temperature at ground level, 5 feet high, and ground surface temperatures under the body should be recorded.
Live specimens, remains, & preserved samples of all insects should be collected.
Documentation of the scene must be included.
Lack of insects or non-native species should also be recorded.
Weather data allows entomologists to adjust life cycle equations to determine time of death.