Estimating Time of Death - Central Bucks School District

Estimating Time of Death - Central Bucks School District

ESTIMATING TIME OF DEATH So Suspects can be eliminated and focus can be put on others What can be used?

Witness statements Body temperature Rigor mortis Lividity Stomach contents Bugs on the body Defining Time of Death Estimated best guess as determined by medical examiner Legal the time the body was

discovered and pronounced dead (this time is recorded on the death certificate) Physiological the time the victims vital functions actually ceased Time of death continued Many deaths are not witnessed occur in sleep, accidental, suicidal, homicide Example: If a serial killer kills a victim in July, but body isnt found until October

What is the time of death? Physiological took place in July Legal October Estimated could be July, or June or August? Measuring Body Temperature Algor Mortis

Normal temp is 98.6 degrees Fahrenheit Body loses heat at a rate of 1.5 degrees per hour Eventually reaches Ambient Temperature the temperature of its surroundings Varies depending on environment Body temperature continued Liver temperature reflects true core

body temperature If body is found soon after death more accurate time of death can be assessed What affects body temperature? Obesity Clothing Surrounding temp. Exposure to sunlight Enclosed environment Rigor Mortis

Stiffening of the body Loss of ATP from muscles Production of ATP depends on supply of oxygen and nutrients ATP is needed to pull the actin & myosin fibers of the muscle apart; therefore, without oxygen, muscles remain contracted

Lost when heart stops Causes muscles to contract and stiffen Rigor mortis ends when tissue begins to decompose @ Temp of 70 degrees F 2 hours after death rigor mortis is

detectable Entire process takes 8 to 12 hours to set in Remains fixed for another 18 hours After another 12 hours muscles relax Therefore can be useful in determining time of death during the first 36 to 48 hours Least effective method of determining time of death because it is extremely variable Fun Fact: Cadaveric Spasm Instantaneous onset of stiffness in the body

Locked in exact posture it was in moment of death Typically occurs under extremely violent physical or emotional circumstances Lividity Real corpses are less attractive than those portrayed in movies

Dark, purplish discoloration of portions of the body Can help determine time of death, and if body was moved Caused by stagnation of blood in vessels Body on back lividity along back and buttocks Lividity continued Color provides clues

Red or pink reveals high levels of oxygen Caused by carbon monoxide or cyanide poisoning, or cold temperatures Purple color poor oxygen levels Severe heart failure, shock, or asphyxia Example of how its used

Faint areas of fixed lividity along back, darker along the front Body was laying on stomach and moved onto back after 4 to 6 hours 2 processes Decomposition Autolysis Self-digestion enzymes of body begin a

chemical breakdown of cells and tissue Putrefaction Bacteria destroy the bodys tissue Bacteria of intestinal tract and some environmental bacteria Thrive in warm & moist environments Freezing stops activities of bacteria Putrefaction is ugly & unpleasant

After 36 hours abdomen, neck, shoulders, and head take on a greenish color Bloating accumulation of gas from bacteria begins in face Skin develops blisters where liquid or serum accumulate Skin begins to marble reveals web-like pattern of blood vessels

Abdomen swells, skin continues to blister. Skin and hair begin to slip from body and fingernails start to slough off Body turns a greenish-black and fluids of decomposition leave through mouth and nose. As body swells tissues break open releasing gas and decomposition fluids Decomposition Rate Faster Obesity Excess clothing Hot & humid

Sepsis blood infection can speed up so 24 hours = 5-6 days Slower Thin Unclothed Cool surface/climate Freezing can protect body for years

Rate of Decomposition Location of body is important: 1 week exposed above ground = 2 weeks in water = 8 weeks in the ground Estimating time of death After a few weeks can be extremely difficult

Body temperature, rigor mortis, lividity no longer are of any use Postmortem decay timeline is modified according to conditions Other possibilities Mummification Bacteria cant live in dry environments

Egyptians used salt and spices to speed drying process so that bodies wouldnt decay Remain in tact for long periods of time so estimating time of death is difficult, if not impossible Adipocere Formation Occurs in wet environments Bodys adipose (fat) tissue turns to soap

Found in water or warm & wet places White, greasy, waxy substance Takes 3-6 months to form Mutter Museum - Philadelphia Sinkers to floaters Bodys dumped in water: Initially sink Rise to surface when gases accumulate

because of putrefaction Temperature of water greatly impacts process Warmer water will float after a few days, cooler water may take weeks or months Bodies found in water display:

Swollen hands and face after 2-3 days Separation of skin from the body after 56 days Loss of fingernails after 8-10 days Floating after 8-10 days in warm water and 2-3 weeks in cold water Stomach contents Contents of victims stomach help determine T.O.D After meal stomach empties itself in 4-6

hours Food is undigested death occurred within 1-2 hours of eating If stomach is empty death likely occurred several hours after eating Also, varies between people Getting Buggy Bugs are usually predictableBut depends on geographic region, locale, time of day, & season Ex: Blowfly

Shows up within the first hour Seek moist areas of corpse to lay eggs Nose, mouth, armpit, groin and open wounds favored Eggs hatch to larvae (maggots) with 24 hours Within 12 days adult flies emerge Blowfly Life Cycle rd instar 3rd Pupa

nd instar 2nd egg st instar 1st Adul t Blowfly Life Cycle pictures 1st instar Adult Pupa 2nd instar

Egg 3rd instar How can this be used? Find only eggs death occurred less than 4 hours earlier Fully grown maggots, but no pupae death occurred less than 10 days earlier Finding pupa indicates that 6-10 days have passed

Circumstances can throw off this schedule: Dont deposit eggs at night Extremely cold conditions may go dormant Ex: if body is warm during day and cool at night maggots may go through lifecycle during the hot times Entomologist may consult climatologist What if someone is dead for 3 weeks? Why would this be complicated?

Adults produced after ~2 weeks Lay their own eggs Follow a similar pattern of life SO corpse may have eggs, maggots, pupae, and adult blowflies present Whaaaat? !? YES! its very complicated Other evidence to estimate T.O.D

Broken watch Victim who missed work for 2 days and is found near his or her front door, dressed in work attire, holding keys, probably heading to work at time of death Victim never showed for a scheduled racquetball game and was found in the garage in exercise clothes likely died while leaving for game Using a combination of these methods will help to best determine the most accurate time of death.

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