1. Meaning, Manner, Mechanism, Cause and Time
DEATH
Meaning, Manner, Mechanism, Cause and Time

2. Death Defined as the “irreversible cessation of circulation of blood”
May also be defined as the cessation of all brain activity
Not easy to pinpoint the exact moment of death (death is a process, not an instant event)
In cases of suspicious or unnatural deaths, an autopsy is performed
Autopsy determines the manner, cause and mechanism of death

3. Manner of Death Natural death – results from age or disease
Accidental death – ex.; car accident
Suicidal death – purposeful killing of oneself
Homicidal death – death of one person caused by another
Undetermined

4. Cause and Mechanism of Death
Reason someone dies is cause of death
Disease, physical injury, stroke, heart attack all cause death
“proximate cause of death” refers to an underlying cause of death as opposed to the final cause
Mechanism of death describes the specific change in the body that brought about cessation of life

5. Time of Death
By establishing a time of death, a suspect may be proved guilty or innocent simply because he or she was or was not in the same place as the victim at the time of death.

6. Liver Mortis Translated, means “death color”
Purplish color is present on the body wherever blood pools…this is called lividity.

7. Lividity
helps determine time of death, position of the body during the first 8 hours after death and if the body has been moved
begins 2 hours after death; discoloration becomes permanent after 8 hours
Temperature affects the time it takes lividity to set in (faster in heat)
Pooling of blood can help determine if the body was moved from one location to another

8. Rigor Mortis Means “death stiffness”
This is temporary and helps determine the time of death
Starts within 2 hours after death and remains for 48 hours
At 12 hours, body is in its most rigid state
Stiffness occurs because skeletal muscles are unable to relax and remain contracted and hard

9. Rigor Mortis and Time of Death
If body shows no visible rigor, it’s been dead less than 2 hours or more than 48 hours
If very rigid, it’s been dead approx. 12 hours
If rigor in face and neck only, rigor has just begun and body has only been dead approx 2 hours

10. Other Factors Affecting Rigor
Temperature (cooler the body, the slower the onset of rigor)
Body weight (higher weight slows the onset)
Type of clothing (heavier clothes accelerates rigor)
Illness (fever vs hypothermia)
Level of physical activity shortly before death (exercise or a struggle accelerates rigor)
Sun exposure

11. Algor Mortis Describes the temperature loss in a corpse
To take a corpse’s temperature, forensic investigators insert a thermometer into the liver
Rule of thumb is that body loses approximately 1 degree Fahrenheit per hour.

12. Stomach and Intestinal Contents
If undigested stomach contents are present, death occurred 0-2 hours after the last meal
If stomach is empty but food is in small intestine, death occurred at least 4-6 hours after a meal
If small intestine is empty but there is waste in the large intestine, death occurred 12 or more hours after a meal

13. Changes of the Eye
If eyes were open at time of death, there is a thin film observed within 2-3 hours
If eyes were covered at death, film is observed within 24 hours

14. Stages of Decomposition
Within 2 days:
Cell autolysis begins
Green & purplish staining occurs from blood decomposition
Skin looks “marbled”
Face becomes discolored
After 4 days:
Skin blisters
Abdomen swells with CO2
Within 6-10 days:
Corpse bloats with CO2; chest & abdomen burst
Fluids leak from body openings
Eyeballs liquefy
Skin sloughs off

15. Clues from Insects
Forensic entomologists – observes and records data about temperature, wind and moisture around the body as well as below it
Insects are attracted to the smell of decompostion and lay their eggs on the dead body within minutes of death
Eggs hatch and feed on the decomposing tissues

16. Life Cycle of a Blowfly
Exhibit different stages as they develop from egg, larva stages, pupa and adult
Each stage of development is present at different times on a corpse and is used to help determine the time of death