1. Time of Death

2. Estimating Time of Death
Algor mortis: Body Core Temperature
Livor mortis: (Lividity)
Rigor mortis
Evidence of Decompositional Process
Insect Larval Instars

3. Algor Mortis Uses body temperature to determine time of death
Normal body temperature is 370C (98.60F)
A body loses heat at a rate of 10C per hour until the ambient temperature is reached
What is ambient temperature?

4. Algor Mortis
Once ambient temperature is reached, you cannot use this method to determine time of death

5. Check Out the Cup This cup of water was warmed up right before class.
Record the temperature in your notes:
Halfway through class:
At the end of class:

6. What are some factors affecting Algor mortis ?
Speeds algor up when...
Slows algor down when...
Temperature
Weight
Clothing
Covering of body
Body position
Sun exposure

7. So, how do we use algor mortis to determine time of death?
To determine time of death take body temperature readings at timed intervals.

8. So, how do we use algor mortis to determine time of death?
Temperature
7:00 am
31.5 C
7:30 am
31.0 C
8:00 am
30.5 C
8:30 am
29.0 C
9:00 am
28.5 C
9:30 am
28.0 C
What should the victims temperature be at time of death?

9. So, how do we use algor mortis to determine time of death?
Approximate time of death?

10. So, how do we use algor mortis to determine time of death?
Put the scale on the Y-axis first, starting at 37 C and working backwards.
Put the scale on the X-axis, starting with the latest time and working backwards.
Plot the known values.
Use a ruler to draw a line through the values, carrying it back to the Y-Axis.
Determine approximate time of death.

11. What Would You Expect If...
The person was larger?
The window was open?
The victim was naked?
The body was covered in a tarp?

12. Now it is your turn to practice!

13. Estimating Time of Death
Algor mortis: Body Core Temperature
Livor mortis: (Lividity)
Rigor mortis
Evidence of Decompositional Process
Insect Larval Instars

14. Livor mortis
* Process when body decomposes and blood seeps down and settles into lower parts of body.
** Causing a purplish red discoloration of the skin.
*** Begins 2 hours after death becomes permanent after 8

15. 3. Livor mortis

16. Livor mortis Observed at 30-120 minutes post-mortem
What do we mean by post-mortem?
8-12 hours post-mortem- maximum color or “fixed” livor mortis due to hemolysis (blood vessels break down)
May occur antemortem (before death) in slow deaths

17. Livor Mortis What else can be determined from lividity?
Position of body following death
Whether a body has been moved post mortem
Heavy things on the body or other pressure
Pressure prevents livor mortis
Squeeze your finger, what happens above where you squeeze? What happens to exactly where you squeeze?

18. Body does have lividity, but shows blanching under pressure.

19. Questions Livor mortis can provide important clues. What are they?
2. What factors could affect livor mortis?
3. How a criminal might be able to disguise the time of death by controlling the ambient conditions that affect livor mortis.

20. So, how do we use livor mortis to determine time of death?
Again, we have a table!
A body doesn’t show any signs of livor mortis. How long has it been since he died?
A body shows light livor mortis on the back. It goes away if you press on it. How long has it been since she died?

21. Now it is your turn to practice!

22. Question #2

23. Question #4

24. Estimating Time of Death
Algor mortis: Body Core Temperature
Livor mortis: (Lividity)
Rigor mortis
Evidence of Decompositional Process
Insect Larval Instars

25. Rigor mortis: The medical condition that occurs after death
Results in the shortening of muscle tissue and the stiffening of body parts
Body stays in the position they are in when death occurs

26. Rigor mortis: Begins within 12 hours and ends after 48 hours
Muscles are trying to use up all of their ATP
After 48 hours, muscle cells begin to autolyse
What does autolyse mean?

27. An unfortunate victim of suicide
An unfortunate victim of suicide. Note that rigor mortis has maintained the position of his arms after the shotgun has been removed.

28. What are some factors affecting Rigor mortis ?
Speeds rigor up when...
Slows rigor down when...
Temperature
Weight
Clothing
Illness
Physical activity
Sun exposure

29. So, how do we use rigor mortis to determine time of death?
Because we know the timing of rigor mortis, we can use a reference table to help us determine time of death.

30. Rigor Mortis Time Event Appearance 2-6 hours Rigor begins
eyelids, Jaws stiffen
After 2 hours
then center of body stiffens
12 hours
Complete Rigor
Entire body rigid
15-36
Slow loss of rigor, small muscles first
Lost in head and neck, last is bigger leg muscles
36-48
Rigor disappears, muscles become relaxed

31. So, how do we use rigor mortis to determine time of death?
Practice:
A body doesn’t show any signs of rigor mortis. How long has it been since he died?
A body shows rigor mortis in the whole body except the head. How long has it been since she died?

32. Now it is your turn to practice!

33. Estimating Time of Death
Algor mortis: Body Core Temperature
Livor mortis: (Lividity)
Rigor mortis
Evidence of Decompositional Process
Insect Larval Instars

34. Decomposition The rotting or break down of all tissues and organs
Bacteria and other organisms aid the decomposition process, just as they decompose plants and animals in the environment.
Occurs in Predictable Pattern
Can be used to help determine Time of Death

36. Stage One - Fresh Stage (Days 1-2)
-Livor, Rigor, Algor mortis
-Autolysis- cellular breakdown
-Some blistering at the skin surface
-Flesh flies, blow flies, ants eating fly eggs

37. Stage Two - Bloat Stage (Days 2-6)
-Gases are made by bacteria that are eating the corpse
-Seepage of fluids from orifices, such as mouth, nose, and anus
-Tissue may become frothy
-Maggots have hatched and begun to feed on the tissue
-Strong decay odors

38. Stage Three - Active Decay Stage (Days 5-11)
-Period of greatest mass loss
-The purged fluids accumulate around the body
-Abdominal wall is broken and carcass deflates
-Adult flies begin to leave the body to pupate, but a lot of maggots remain

39. Stage Four - Advance Decay Stage (Days 12-25)
-Remains consist of dry skin, cartilage and bones
-Most insects have moved on
-Can depend on the environment

40. Stage Five - Dry Stage (Days 25+)
-Mainly bone and hair left
-Odor is mostly of soil
-This stage could last for several months to years.