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Forensic Analysis: Time of Death and Age Determination

A description on how forensic scientists use different processes to determine the time of death, age, and gender using temperature, decomposition, bones, bugs, etc.

Karistie Hellenbarger

on 25 March 2011

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Transcript of Forensic Analysis: Time of Death and Age Determination

Forensic Analysis Time of Death Body Temperature Equation: Body Temp - 1.05 degrees Celcius per hr. until body = surrounding temp. Affected by surrounding temp., humidity, air movement, fat levels of body, etc. Thermometer is
stuck into chest
cavity. Thermometer is stuck into chest cavity Affected by surrounding temp., humidity, air movement, fat levels, etc. Decomposition The longer the
body sits,
the more it
decomposes. Time Physical Appearance of Body Insects Present at that Stage
0-3 days 0-3 days Proteins and carbohydrates in the deceased body begin to break down. Blowflies e.g. Bluebottle flies, Syrphidae flies
4-7 days Body is starting to decay and causes the abdomen to inflate because of the gases inside. Fly larvae and beetle e.g. Rove Beetles
8-18 days 8-18 days Decay is well and truly setting in; the abdomen wall begins to break down. Ants, cockroaches, beetles and flies
19-30 days The decaying body enters a stage know as 'post-decay'; in wet, humid conditions, the body is sticky and wet; in hot dry conditions, the body is dried out. Beetles and mites e.g. Springtail beetle, Acari, Nematocera (present only during the winter months), Brachycera
31 and over days The bones, skin and hair that remain no longer give off a powerful stench and smell just like the soil surrounding it.
Time Time Physical Description Insects Present 0-3 days

4-7 days

8-18 days

19-30 days

31+ days Protiens and carbohydrates begin to break down.

Body starts to decay, abdomen starts to inflate due to gasses.

Decay setting in, abdomen begins to brek down.

Post-decay: in wet, humid conditions, the body gets wt and sticky; in dry conditions, the body dries out.

Bones, skin, and hair no longer have unpleasent scent, they begin to smell like the soil surrounding it. Blowflies, Bluebottle flies, Syrphidae flies

Fly larvae, Beetles, Rove Beetles

Ants, Cockroaches, Beetles, Flies

Beetles, Mites, Springtail Beetle, Acari, Nematocera, Brachycera Hardening (Rigor Mortis) Muscles in the body begin to
stiffen from a lack of blood
and oxygen. First seen in eyelids and jaw. Spreads
to rest
of the
body within
6-12 hours. Receds after another 6-12 hours. Might not occur if surrounding temperature is very low. Body Temp. Body Stiffness Time Since Death Warm
Cold Not Stiff
Not Stiff Less than 3 hrs
3-8 hrs.
8-36 hrs.
36+ hrs.

Eyes Thin cloudy film is found over eyes after time of death within 3hrs. Skin Color Approx. 48 hrs. after death, skin turns green tint due to breeding of bacteria.
Starts in lower stomach then spreads out.
Hands and feet are last. 4-7 hrs. after death, veins will become more visable b/c they are closer to surface. Blood Pooling (Hypostasis) Bloods stops flowing
& begins to pool into lower parts of body,
skin turns a pink-red color. Process is completed 6 hrs. after death. Also helps determine how the person died. Digestive System The location of the food can help determine when there last meal was. Time since last meal Location of Food Seconds

3 hrs.

6 hrs. Pass through oesophagus & down into stomach.

Leaves stomach, heads to small intestine.

Half way through small intestine & begins to go through large intestine. Age Young Person
-Length of Bones
-Extent of Fusion
of the Epipysis
-Status of Teeth (teeth eruptions) Person Over 20
-Epiphysis on the sternal end of the clavicle (fuses completley at age 30)
-Sternal ends of the 4th rib cage changes as people get older Over 30
-Signs of lower back problems
-Bones are more dense and porus
-Increase in arthritic projections
-Work related injuries to the bone Gender Pubis Bone
Elongated in women after child birth Pubis Bone
Elongated in women for childbirth Skull
-Men have larger heads
-Women's are smaller and more delicate 85-90% of the time, gender can be determined from the skull. Quality of Bone Male Female -General Size
-Supraorbital margin
(Brow Ridge)
-Mastoid process
(Projection at base of skull)
-Occipital bone
(Back of the skull)
(Between and above eyebrows)
-Gonial Angle
(Jaw angle)
(Roof of the mouth)
-Occipital condyles
(Joint between skull and vertabrae) -Large


-Muscle Lines Marked



-Larger, Broader, U-Shaped

-Large -Small


-Muscle Lines Not Marked


-Wide Angle

-Small, Parabola

-Small Race Can be determined by cheek
bones & eye sockets. Racial mixing makes it hard & complex to determine. Stature Regression Formula for Estimating Maximum Living Stature (with standard errors) from Maximum Long Bone Length W Stature 3.26 x (humerus) + 62.10 = stature +/-4.43cm
3.42 x (radius) + 81.56 = stature +/-4.30
3.26 x (ulna) + 78.29 = stature +/-4.42
Weight Wt (in lbs) = 4.4 x (stature in inches) - 143
Time of Death A body becomes skelitilized after 8 months of being unburried.
1-2 yrs. if buried Manor of Death bullet fragments, holes, breaks, etc. Works Cited Eyes become
soft due to
less fluid
behind eyes. Skull
Men have larger heads
Women's are smaller and more delicate Skull
Men have larger heads
Women's are smaller and more delicate Skull
Men have larger heads
Women's are smaller and more delicate Skull
-Men have larger heads
-Women's are smaller and more delicate - library.thinkquest.org/04oct/00206/text_ta_time_since_death.htm

- www.deathrefrence.com/Py-Se/Rigor-Mortis-and-Other-Postmortom-Changes.html

- http://www.anthro4n6.net/forensics/ European American Sub-Saharan
Indian African By: Kristie Harms & Kate Shellenbarger Bones
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