1. The Medical Examiner

2. The Medical Examiner
The Medical Examiner
Vs.
The Coroner

3. The Medical Examiner
The Medical Examiner is a medically qualified government
officer whose duty is to investigate deaths and injuries that
occur under unusual or suspicious circumstances, and to
perform post-mortem examinations.
The Medical Examiner is required to have a medical degree,
often with additional education in forensic pathology.
Typically, The Medical Examiner is appointed to his/her
position.
The Medical Examiner’s task is to determine cause, time
and manner of death.

4. The Medical Examiner
The Coroner are often elected (rather than appointed) officials,
and usually do not need to hold any medical qualification.
As finders of facts, they use Medical Doctors to determine
cause, time and manner of death.

5. The Medical Examiner
What are some of the questions a M.E. is asked to answer?
The reason someone dies is called Cause of Death.
Ex. Heart attack, disease, stroke, physical injury.
2) The way someone dies is called Manner of Death.
Natural Causes
b. Accidental Death
c. Suicide
d. Homicide
e. Unknown

6. The Medical Examiner 3) Identification
In some cases it is not obvious who the victim is. It is
the M.E. job to I.D. the victim.
The M.E. will use many of the following to determine
I.D.

7. The Medical Examiner Dental Impressions DNA Skeletal Remains
Can you think of any other means
of identification?

8. The Medical Examiner 4) Time of Death
During an autopsy, the M.E. wants to determine when the
person died.
By establishing time of death, a suspect may be proven
innocent simply because he/she was not in the place as
the victim at the time of death.
On the other hand, a suspect my remain a person of
Interest if he/she was in the same area at the time of
death.

9. The Medical Examiner How is the time of Death Established?
1) Livor Mortis
= Death Color
When the heart stops beating blood will settle or pool in
the lowest parts of the body.

10. The Medical Examiner
Pooling of blood in the body, known as lividity, will
provide clues to how long the person has been dead.
Determining time of Death with the use of Lividity.
Lividity begins to show about two hours after death.
Discoloration is permanent after about eight hours.
Between two and eight hours, if the skin is pressed,
the color will disappear.
After eight hours, if the skin is pressed, the color will
remain.

11. The Medical Examiner
Besides Time of Death, lividity can provide other clues.
Because gravity pulls blood toward the ground, livididty
can reveal the position of the body at the time of death.

12. The Medical Examiner 2) Rigor Mortis = Death Stiffness
Rigor Mortis is the temporary stiffness of the body after
death.
Determining time of Death with the use of Rigor Mortis.
Rigor Mortis starts about two hours after death.
Rigor Mortis starts at the head and works its way to the legs.
After 12 hours the body is at it stiffest state.
Generally, stiffness gradually disappears after hours.

13. The Medical Examiner
Suppose a detective comes to a crime scene and the
victim’s body is not in rigor. What is the time of death?
Answer: Less than 2 hours or more than hours.
Suppose a detective comes to a crime scene and the
victim’s body is in full rigor. What is the time of death?
Answer: Around 12 hours.

14. The Medical Examiner 3) Algor Mortis = Death Heat
Algor Mortis is the cooling of the body after death.
Determining time of Death with the use of Algor Mortis.
Determining time of death using the cooling of the
body (taken from the liver) is sometimes difficult.
Many factors contribute to how the body cools. Such as:
Environment Temp
Victim’s clothes, if any
Victim’s Weight

15. The Medical Examiner
Determining time of Death with the use of Algor Mortis.
0 – 12 hr after death
12 – ? hr after death
Body loses 1.4° F per hr
Body loses .7° F per hr
These values are just estimates and my vary depending
upon many other factors.
We can average these values and use 1° F per hour.

16. Answer: Since the body cools at a rate of 1° F, 6 hrs.
The Medical Examiner
During an autopsy the liver temperature is determined
to by 92.6° F. Approximately how long has the body been
dead?
98.6° F – 92.6° F = 6° F
Answer: Since the body cools at a rate of 1° F, 6 hrs.

17. The Medical Examiner 4) Stomach Contents
In general it takes four to six hours for the stomach to
empty its contents into the small intestines.
It then takes another 12 hours for the food to leave
the small intestine.
It takes about 24 hours for food to complete the
the digestion cycle.

18. The Medical Examiner From this information it can be concluded that:
If undigested food is present in the stomach, then
death occurred zero to two hours after the last meal.
2) 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.
3) If the small intestine is empty but food is found in the
large intestine, death occurred 12 hours or more after a
meal.

19. The Medical Examiner 5) Decomposition
A corpse decomposes in predictable ways over time that
can help determine time of death.
Within two days after death:
Cell autolysis (self digestion) begins
Skin turns green/purple from blood decomposition

20. The Medical Examiner After four days: Skin starts to blister
The abdomen swells with gas released from bacteria
in the intestines.
Within six to ten days:
The build up of gases cause chest and abdomen to
burst.
Fluids begin to leak from the body openings.
Tissues begin to liquefy.
The skin sloughs off the body.

21. The Medical Examiner 6) Insects
The presence of insects on a body can provide detailed
information about the Time of Death.
In fact, insects are so useful in crime scene investigation
That there is an entire field dedicated to this study and
Practice and it is called Forensic Entomology.

22. The Medical Examiner
Within minutes of death, certain insect arrive to lay their
eggs on the body.
For example, blowflies lay their eggs which soon turn into
larva. The larva feed on the decomposing flesh.
Sometime after, wasps lay their larva on the body which
feed on the blowfly larva.
In addition, each stage of decomposition attracts different
insects.

23. The Medical Examiner
Let’s look at the Blowfly and how it can help us determine
Time of Death.

24. The Medical Examiner
Similar to other insects, blowflies exhibit different stages
of development:
Eggs
Larva

25. The Medical Examiner
Pupae
Adult

26. The Medical Examiner
Because we know how long it takes for the various stages
of development, forensic entomologists can determine
when the blowflies arrived by studying the insects on the
corpse.
If we know when they arrived we can determine approximate
time of death.

27. The Medical Examiner Blowfly Life Cycle Stage Size (mm)
When first appears
Phase Duration
Characteristics
Egg 2
Soon after death
8 hrs
Found in moist areas
Larva 5
2 – 5 days
20 – 56 hrs
Black mouth visible
Pupae
10-17
8 – 20 days
4 – 12 days
Immobile
Adult
Varies
21 – 24 days
Several Weeks
Flight possible

28. The Medical Examiner
If a corpse contains blowfly eggs approximate time of
death is?
Answer: Less then 24 hrs
If a corpse contains blowfly larva approximate time of
death is?
Answer: Between 2 and 5 days.
If a corpse contains blowfly pupae approximate time of
death is?
Answer: Between 18 and 24 days.