Time of Death

1. Time of Death

2. The Face of Death

3. 17th Century Coma or weak heartbeat = DEAD and BURIED Fear of being buried alive bell in coffin “Saved by the bell” "All I desire for my own burial is not to be buried alive." - Lord Chesterfield, 1769

4. "Have me decently buried, but do not let my body be put into a vault in less than two days after I am dead." - deathbed request of George Washington. • Waiting Mortuaries • Established in 17th century • Those thought to be dead…placed on cots and observed until body began to rot • Now…. they’re dead

5. Is a person with a heartbeat alive even if there is no brain activity? • What do you think?

6. Cessation (Death – End of Life) • Somatic death • Death of the entire body • Legal definition: • Death of upper brain & brain stem • Cellular death • Death confined to cells or tissues in the body “Irreversible cessation of circulation of blood.”

7. Lend me a looking glass;If that her breath will mist or stain the stone,Why then she lives. Shakespeare, King Lear

8. Autolysis • When a cell dies, it breaks down • Breakdown = autolysis • Definition: the destruction of a cell through the action of its own enzymes • Once enough cells begin autolysis, life cannot be restarted • Cell membrane dissolves – enzymes and other cell contents spill – digest surrounding tissues

9. Manners of Death • Natural • death results from natural disease processes • Accidental • Caused by unplanned events • Suicidal • Person purposefully kills oneself • Homicide • Caused by another person • Undetermined

10. Categorize Manner of Death • A man with a heart condition is attacked and dies from a heart attack during the assault • Accident or homicide? • An elderly woman dies after being kept from receiving proper health care by her son. • Natural or homicide? • Both cases = homicide. Proving in court that manner of death was a homicide may be difficult

11. Cause of Death • Cause of death = reason someone dies • “Proximate cause of death” – refers to an underlying cause of death… rather than FINAL cause of death • Ex: If someone is exposed to large amounts of radiation and then developed cancer • Proximate cause of death? • Radiation exposure!

12. Mechanism of Death • Mechanism of Death = the specific change in the body that brought about the cessation of life • Ex: If cause of death is shooting, what would be the mechanism of death? • Loss of blood, cessation of brain function or exsanguination (total blood loss) • Ex: If cause of death is heart attack, what would be the mechanism of death? • Heart stopping to beat or pulmonary arrest

13. Estimate Time of Death • Evaluate the stage of decomposition that the body was found in

14. Rigor Mortis: Rigidity of Death • In mammals • Body stiffening of muscles in the position that they are in when death occurs • First eyelids, neck, jaw, then other muscles (from head to toe)

15. Rigor Mortis • How? • Aerobic respiration stops, anaerobic respiration begins • Conversion of sugar to pyruvic acid to lactic acid • 2 ATP anaerobic vs. 36 ATP aerobic • Lack of ATP forces muscles to stay contracted

16. Rigor Mortis Inside cell • Ca2+ naturally flow from fluid surrounding muscle cells to inside the cell • To relax muscles, Ca2+ must flow back across the cell membrane • Requires ATP energy, not enough ATP after death • Muscles stay contracted Fluid surrounding muscle cells

17. Rigor Mortis • Timeline • Begins 3-4 hours after death • Maximum stiffness 12 hours after death • Stiffness decreases until 72 hours after death

18. Cadaveric Spasms • Occurs at the moment of death • Most common when person has died violently • Involves a certain group of muscles • hand, forearm

19. Livor Mortis“Death Color” • Lividity • Dark purple discoloration of the skin resulting from the gravitational pooling of blood to the lowest points of the body • Dependent on body position • In deaths from carbon monoxide poisoning, it is classically described as "cherry red“ • Onsets immediately

20. Livor Mortis • Duality of distribution • After 10-12 hours lividity becomes “fixed” • If body is moved there will be a dual lividity pattern

21. Livor Mortis Livor mortis

22. What assumptions can be made about the victim based on lividity? • If this victim was found upright in a chair, what else can be assumed?

23. Algor Mortis

24. Algor Mortis • In average environmental conditions/temperatures, a few simple rules of thumb can be helpful: • Bernard Knight’s Formula

25. Algor Mortis“Death Heat”“The Chill of Death” • Most useful single indicator of time of death within 24 hours post mortem • “Body Cooling” • Estimated that the body temperature drops approximately 1.5F/hour • Cooling effected by: • Location, weather, clothing, activity at death, victim size

26. Algor Mortis • To find the standard temperature of a corpse, a thermometer is inserted into the liver • Why the liver? Standard location so investigators can compare results

27. Ocular Changes

28. Aqueous Humor • Clear, watery fluid in the eye • Can measure the amount of potassium (K+) in the aqueous humor to determine time of death • K+ amounts increase for up to 104 hours after death • Temperature at time of death effects K+ levels

29. Stomach Contents • Shows nature of last meal & abnormalities • Stomach starts to empty within 10 minutes • If the victim had a… • Light meal: will stay in stomach 1-2 hours • Medium meal: will stay in stomach 3-4 hours • Large meal: will stay in stomach 4-6 hours • Emotional state effects stomach emptying