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

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

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

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

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.

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

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

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

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

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

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.

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

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

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

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

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