TIME OF DEATH
Forensic science provides a number of solutions to
solving the mystery question of when a person died.
The longer it has been since the death, the less
accurate the estimation given by forensic pathologists.
1. BODY TEMPERATURE
• The core body temperature drops at an estimated
rate of 1oC each hour from the time of death.
• Factors affecting this estimation:
Temperature at the scene of crime
Humidity levels
Air movement
Fat levels in the body
etc
• The liver is our largest
organ, so Scene of
Crime Officers measure
core body temperature
from here.
Can you read the temperature
on this thermometer? It is
38oC
ACTIVITY 1
Core Body Temperature (oC)
Core Body Temperature of deceased
over time
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
a)
b)
c)
d)
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Time after Death (hours)
What would you expect the
body temperature to be 5
hours after death? (Hint:
See red line on graph)
What would you expect the
body temperature to be 10
hours after death?
If the deceased has a core
body temperature of 35
degrees Celsius, how long
has the person been dead
for?
Why do you think the
temperature stops dropping
at 24 degrees Celsius?
Explain.
2. HARDENING
• Stiffening of the corpse occurs between just 30 minutes and 3 hours
after death. The process is called rigor mortis
• Occurs as the muscles in the body begin to stiffen from a lack of
blood and oxygen.
• After the first stiffening of eyelids and jaws of the victim are
observed, rigor mortis spreads throughout the whole body in
approximately 6 to 12 hours, before receding again after another 6
to 12 hours.
3. THE TRUTH LIES IN THE EYES
• A thin cloudy film is developed over the eye within 3 hours
after death has occurred. Pupils dilate (get larger)
• The eyeballs become softer as a result of less fluid pressure
behind the eye and the degree to which this has occurred
can be used as a measure of the time since death
• When you do your squid dissection, notice the cloudiness
in the eyes of the squid.
4. SKIN COLOUR
• Straight after death, the body turns a whitish grey colour.
• About 48 hours after death, bacteria begins to breed on the skin,
giving the skin a greenish tone. The tinge starts in the lower
stomach area, spreading outwards and affecting the hands and feet
last.
• About 4-7 days after death, the skin will acquire a marble-like
appearance, as the veins in the body become closer to the surface,
thus becoming more easily visible.
Pig Sample 1
Pig Sample 2
ACTIVITY 2
Place the skin colour samples of pigs in the following order:
Alive, 48 hours after death, 4-7 days after death.
Pig Sample 3
5. BLOOD POOLING
• The pooling of the blood can be a vital clue
in determining the time of death and is
known as hypostasis.
• This occurs when the blood ceases
flowing, settling in the lowest parts of the
body and in turn, causing the skin to
become pink and red in colour.
• This process is complete in up to 6 hours
after death.
• Blood pooling can also help us determine
the manner of death.
6. THE DIGESTIVE
SYSTEM
2-4hrs
ACTIVITY 3
A corpse of a sponge was found washed
up on a nearby beach at 8:00am today.
The victim was identified by Mr Partick
Star to be that of Mr SpongeBob
SquarePants. Mr SquarePants is known
to have the same digestive system typical
of the human species.
Witnesses say they saw Mr SquarePants
eating at Krusty Krab around 7:00pm
yesterday.
5-6hrs
12-24hrs
Upon examination of Mr SquarePants’
stomach contents, masticated and
partially digested Krabby patty burgers
were discovered. What information can
you provide investigators with?
An arthropod is an invertebrate
animal having an exoskeleton
(external skeleton), a segmented
body, and jointed appendages.
7.
FORENSIC ENTOMOLOGY
is the use of the insects, and
their arthropod relatives that
inhabit decomposing remains to
aid legal investigations.
MAGGOTS (Larvae)
ACTIVITY 4
Use the following slide to work out how long
this potato had been rotting on the ground.
Adult flies attracted to moist areas and
decaying matter. Adults live 3 to 4 weeks.
3 to 4 days
3 to 4 days
8 to 12 hours
Larvae produced. These feed on protein and
grow rapidly. At the end of the growth phase,
larvae move to a drier place to pupate
4 to 7 days