• Rate: Measures changes in the body by a process that takes place at known rates.
• Rigor, Algor, and Livor Mortis
• Concurrence: Compares the sequence of events that took place at known times with the time of occurrence of the event under investigation.
• A wristwatch stopped by a blow during an assault.
• The extent of digestion of the last known meal.
Rigor Mortis: Stiffness of Death
• Classic marker of death
• Rigidity of the body
• Produced by metabolic (chemical) changes
• More rapid in small muscles
• Heat accelerates – Cold decelerates
• Full Rigor: 6-24 hours, 12 average
• Very subjective (depends on experience)
• Scientifically Unreliable
Algor Mortis: Temperature of Death
• Body temperature is a narrow range (not fixed).
• Illness, decomposition, infection, and absorption of heat can raise body temperature.
• Many formulas to determine TOD.
• Clothing, bodies of water, fatness, ventilation, age, weather conditions.
• Rectal or liver temperature needed.
Livor Mortis: Color of Death
• Setting of blood to dependent parts of the body.
• Cardiac activity stops, and hydrostatic pressure of the blood no longer keeps the blood vessels open.
• Hydrostatic Pressure: The pressure exerted by blood on walls of blood vessels, keeping them open.
• Color depends on skin pigment and additional compounds in the blood (e.g. carbon monoxide).
• Generally dark blue/purple.
• Body areas touching the ground will be blanched (white).
• Usually reaches maximum appearance 8-12 hours.
Dependent vs Fixed Lividity
• Dependent: Just after death, blood flows to the dependent parts of the body and settles.
• Lowest parts of the body due to gravity.
• Fixed: After a period of time, the blood becomes fixed in its location and will not move (even if the body is moved).
Patterned Livor Mortis
• Can give class evidence of where the person died and was laying.
• The lividity is consistent with the position of the body.