Download Estimating Time of Death Reference – page 73

Estimating Time of Death Reference – page 73
In order to estimate time of death, many factors need to be considered. It is
not possible to look at any one factor and determine an exact time of death.
Algor Mortis: temperature of death
1. Loss of body temperature at rate of 1.4° F per hour for the first twelve hours after death.
1.4 degrees/hour x 12 hours = 16.8° F lost in the first 12 hours
2. Loss of body temperature continues after the first twelve hours at a rate of 0.7° F per
hour.
3. Factors affecting heat loss include:
a. Cooler air temperature (body loses heat faster)
b. Warmer air temperature (body loses heat slower)
c. If the body is clothed, heat loss is slower.
d. If the body is overweight, heat loss is slower.
e. If the body is thin or small, heat loss is accelerated.
f. In water, body cools faster than on land.
Livor Mortis: The color of death
This involves the pooling of the blood in the parts of the body that are lowest to the ground. This
is also known as lividity. If the body is face-down, for example, blood would pool in the face,
stomach and fronts of legs.
Livor mortis begins two hours after death.
Lividity becomes permanent after eight hours.
If the skin is discolored but turns white when touched, lividity has not been completed
and the body has been dead between two and six hours.
Rigor Mortis: stiffness of death
Rigor mortis occurs in different stages:
Beginning of rigor mortis begins at two hours after death; begins in eyelids, face and
neck
Peak rigor (highest level of stiffness): 12 hours after death
Loss of rigor: gradually begins after 12 hours
No rigor: 36 hours after death
Factors affecting rigor mortis:
1. ambient temperature
a. cooler air slows the onset of rigor
b. warmer air speeds up the onset of rigor
2. Clothed body experiences faster rigor
3. If the person was exercising or running prior to death, onset of rigor will be faster due to
accumulation of lactic acid and lack of oxygen
Stomach Contents
At autopsy, the digestive tract is examined. If it was known when the person ate last, it might be
able to estimate time of death based upon food present or absent in the digestive tract.
If undigested stomach contents are present, then death occurred zero to two hours after
the last meal.
If the stomach is empty but food is found in the small intestine, then death occurred at
least four to six hours after a meal.
If the small intestine is empty and wastes are found in the large intestine, then death
probably occurred twelve or more hours after a meal.
Insect Evidence
Life Cycle for Blowfly
21-24 days
8-12 days
Soon after death
4-5 days
1.8 days
2.5 days
Adapted from Bertino Forensics; Obtained during Summer Institute provided by Humble ISD Education Foundation