1. Death Investigation

2. Death Investigation and Forensic Pathology
Biology defines a living thing as follows:
*any organism or living form that show’s characteristics of life
Characteristics of life:
an organized structure, being made up of cells
requires energy to survive or sustain existence
ability to reproduce
ability to grow
ability to metabolize
ability to respond to stimuli
ability to adapt to the environment
ability to move
ability to respire

3. Medical determination of death (the end or cessation of life)
Cessation of heart beat and all body functions shut down
Heartbeat present
no heartbeat/flat line

4. Manners of Death
Natural: the body ceases to function on its own; May be contributing factors such as terminal illness, heart disease etc.
Accidental: no due to natural causes, suicide or homicide; usually due to some misadventure or risk taken by an individual
Suicidal: deliberate taking of one’s own life
Homicidal: deliberate taking of someone else’s life (murder)

5. Causes, manner, and mechanism
Cause of death: the immediate reason for a person’s death; disease or injury that initiated the events leading to death (this is usually determined at autopsy if not already evident)
Manner: a mean by which someone dies (natural, accidental, suicide, homicide)
Mechanism: the specific body failure that leads to death; the physical abnormality produced by the cause of death that resulted in an incompatibility with life.

6. Case Examples
The body of a 25 year old male is found in some brush along a creek bank. The body is sent to the medical examiner for autopsy. The medical examiner determines that there has been a severe brain hemorrhage from being hit in the head with a blunt object. (blunt force trauma to the head).
Cause of death: blow to the head
Manner of death: homicide
Mechanism of death: bleeding in brain

7. On the set of Grey’s Anatomy, Bailey leaves her lunch in the staff refrigerator. Richard takes the lunch at eats it then falls asleep in the on call room. Bailey finds out that Richard ate her lunch. She goes to the on call room and smothers him with a pillow. Richard dies.
Cause of death: smothering
Manner of death: homicide
Mechanism of death: asphyxia

8. William Blake has set Siegfried and Roy’s tiger on fire
William Blake has set Siegfried and Roy’s tiger on fire. Siegfried stabs him in the aorta. The ambulance gets into a wreck on the way to the hospital. Blake dies.
Manner of death: homicide
Mechanism of death: loss of blood
Cause of death: stabbing

9. A man is shot while committing a robbery. The man stabilizes
A man is shot while committing a robbery. The man stabilizes. Later he develops pneumonia followed by kidney failure and liver failure. He dies. He had prior lung and heart disease and probably would have survived if not for these diseases.
Manner of death: homicide????
Cause of death: cause of death
Mechanism of death: heart failure

10. Classification of Traumatic Death
Mechanical
Sharp force (knife)
Blunt force (gunshot, baseball bat,etc.)

11. Mechanical (sharp force vs. blunt force)
Sharp force: blunt force:
Sharp edges rough edges
Incised wound laceration

12. Mechanical (sharp force)
Difficult to determine the size of blade from the size of the would
Smaller/Larger blade may cause larger/smaller wound
Mechanism of death is usually loss of blood.

13. Mechanical (blunt force—firearms)
Most common homicidal & suicidal wound in the United States
Damage produced is due more to the velocity of the projectile than the mass
Wounds can be
Penetrating: entrance wound but no exit wound
Perforating: entrance and exit wound
Escaping gases may affect the appearance of the wound.

14. Contact or near contact wound
Gases burn (blacken skin)
Gasses into wound tears the skin (blown out look)
Possible head explosion

15. Intermediate range wound
Unburned powder creates stippling around wound

16. Distance Gunshot Wound
Circular hole with rim of abraded skin
Note: size of bullet cannot be determined

17. Entrance versus Exit Wound
Usually entrance wound is smaller than exit wound
Reason: nothing behind the exit wound to prevent explosive burst
Exception: exit wound is shored. Tight fabrics or body against an object prevents the explosive outburst. A shored exit wound loos like an entrance wound (which is always shored by the body)

18. Damage relates to Kinetic energy
Exiting bullet “wastes” kinetic energy
Hollow point bullets designed to expand and stay in the body longer; in reality not much difference.
Damage due to rebounding tissue
Bullet velocity is too fast to tear tissue instead it pushes tissue aside creating a cavity
Tissue tears upon rebound along with some surrounding tissue
Damage is about 3X diameter of a bullet

19. Mechanical (non-firearm blunt force trauma)
Most common is a car accident.
For homicides beatings that almost always involve a blow to the head
Mechanism of death is usually drowning in blood.
Rarely will one blow to the head knock a person unconscious.
Contusion: accumulated blood in tissues outside the blood vessels (internal bleed)
Hematoma: large contusions (blood tumor); goose egg on the head

20. Stimulants: may cause seizures and death Carbon monoxide:
Chemical Trauma
Overdoses:
depressants (including alcohol) slow communication between nerves, brain and body. Can cause coma.
Stimulants: may cause seizures and death
Carbon monoxide:
Binds hemoglobin and blocks oxygen; death by asphyxiation.
Other poisons interfere with a variety of essential biological functions

21. Thermal and Electrical Trauma
Thermal trauma
Hypothermia: excessive cold
Hyperthermia: excessive heat
Both are hard to diagnose
Death from fire is usually due to carbon monoxide poisoning
Electrical Trauma
Heartbeat relies on an electrical charge signal from the brain
Low voltage causes heart to “quiver” then stop.
Extremely high voltage causes heart to contract then start beating again

22. Physiological or medical determination of the time of death:
The time at which the body ceases to function:
Heartbeat stops
Vital organs shut down
All bodily functions stop: breathing, brain waves

23. Determining Time of Death
If there is another person present, it is usually easier to determine the time of death. This is not always the case. The recent death of Supreme Court Justice Scalia is one example:
“The next morning, Scalia did not show up for breakfast. Poindexter at first thought he might be sleeping late, but eventually he grew concerned. Late Saturday morning, he and one other person knocked on the door to Scalia’s room, an expansive suite called the “El Presidente.” When there was no answer, they went inside. “Everything was in perfect order. He was in his pajamas, peacefully, in bed,” Poindexter said.” (Washington Post.)

24. Estimated time of death: a best estimate based on available information
When was the person last seen or heard from
Who was the last person to have contact with the deceased while still alive
What medical illnesses did the deceased have
Age
Circumstances surrounding death

25. Legal time of death: the time when the body was discovered or
pronounced dead by another person usually medical personnel
or law enforcement. This is the official time of death that is
recorded on the death certificate.

26. Examining the Corpse to Aid in Determining Time of Death
Rigor mortis: natural contraction and relaxation of the skeletal muscles after death due to chemical changes and a loss of ATP (adenosine triphosphate)
Beings usually in the small muscles of the face and spreads to larger muscles
Signs usually appear within the first 2 hours after death
Can be used to approximate time of death because it occurs within the first hours
Common misconception: Rigor does not leave the body. This is wrong because it does leave and the muscles will eventually relax.

27. Rigor Mortis
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28. Livor Mortis
Lividity or (livor mortis) occurs when the blood stops moving in the body because the heart has stopped pumping.
Remaining blood will settle due to gravity giving the body a purple discolored area where the blood settles.
Lividity begins within 30 minutes of death and lasts for up to 12 hours.
Within the first 6 hours, it can be altered by moving the body. After 6 hours it becomes fixed because the blood vessels break down.

30. Algor Mortis
Body temperature begins to drop after death and skin becomes less elastic
A corpse of average weight in an air temperature of 20 degrees Celsius would experience a temperature drop of approximately 1.5 degrees Celsius per hour. (normal body temperature is 37 degrees Celsius)
Temperature change is faster: thin or malnourished corpse; low temperatures or windy conditions
Temperature change is slower: obesity; fever at time of death; high air temperature

31. Measuring Body Temperature
Human body temperature varies but on the average is 98 ̊F or 37 ̊C. Person’s with higher metabolism usually have slightly higher body temperatures.
The location where temperature is taken also affects reading: mouth (98 or 37) armpit (97.6 or 36.4)
Rectal temperature is closest to core body temperature.

32. For death investigation, the temperature can be determined by the pathologist using the most appropriate method but rectally is the most accurate.

33. Stages of Decomposition
Initial decay: the fresh stage
Corpse appears normal on the outside
Internally decomposition is occurring (autolysis)
Skin slippage starts due to fluid leaking out of cells
Putrefaction: bloated stage
Odor of decaying flesh present
Corpse appears swollen due to gases produced during internal decomposition processes; most noticeable in abdomen, mouth, tongue, genitalia
Bacteria inside body are feeding and producing gases

34. Butyric Fermentation: Dry Decay:
Black putrefaction:
very strong odor
Parts of flesh appear black
Gases escape and corpse collapses (body is dissolving itself)
Butyric Fermentation:
Corpse begins to dry out; most flesh is gone
Dry Decay:
Corpse is almost dry; further decay is slow due to lack of moisture
Decomposition

35. Factors Affecting Decomposition
Warm, wet weather speeds up decay
Cold, dry weather slows down decay
Large masses of larvae feeding on the corpse can also speed up decomposition because the temperature increases

36. Examination of the Eye
The vitreous humor of the eye shows an increase in potassium level up to 24 hours post mortem.

37. Autopsy The pathologist will gather information about the deceased:
Basic statistics such as height, weight, age, sex, ethnicity
Record external observations: marks, scars, tatoos, bruising, wounds, etc.
Recover and store any trace evidence
Extract blood and urine samples for toxicology or other studies

38. Cut a Y-incision and remove breast plate
Remove, examine and weigh major organs
Collect stomach contents and examine
Take blood, urine and tissue samples if not already done
Open skull and examine brain
Return bodily contents; stitch up skull and body chest
Write up autopsy report/conclusions

39. Cool Jobs: Forensic Entomology
What do they do?
Forensic entomologists apply their knowledge of entomology to provide information for criminal investigations.
Forensic entomology is the application of entomology (knowledge of insects) to criminal and civil investigations.
A forensic entomologist’s job may include:
Identification of insects at various stages of their life cycle, such as eggs, larva, and adults.
Collection and preservation of insects as evidence.
Determining an estimate for the postmortem interval or PMI (the time between death and the discovery of the body) using factors such as insect evidence, weather conditions, location and condition of the body, etc.
Testifying in court to explain insect-related evidence found at a crime scene.
Did you know? Maggots can be used to test a corpse for the presence of poisons or drugs. Some drugs can speed up or slow down the insect’s development.
Cool Jobs: Forensic Entomology
Discovery Video

40. Life Cycle of the Insect
Adult:
Hard body
Segmented
Six legs
One or two pairs of wings
Three distinct body regions
Head
Thorax
abdomen
Larval Forms
Soft body
Often no legs
Segmented
Worm-like
Insects are one of the most numerous and diverse groups of
Organisms with approximately one million species described
and named.

41. Usually first to arrive to the corpse after death.
The insects of forensic interest are flies (dipterans) and beetles (coleopterans).
Two groups of flies, the blow fly and the flesh fly, live on carrions or carcasses.
Usually first to arrive to the corpse after death.
Adult blowfly: iridescent blue, green, copper or black body
Adult flesh fly: gray with three distinct longitudinal dark stripes on the dorsal thorax.
Some beetles will also occupy the corpse but are less common and arrive later.
Some flies prefer the fresh corpse and others later stages such as bloated or dry.
The ordered series of insects arriving to the corpse is called a succession. t t

42. Insects as Evidence
Forensic entomologists use their knowledge of insects and their life cycles and behaviors to give them clues about a crime.
Most insects used in investigations are in two major orders:
1 – Flies (Diptera) and
2 – Beetles (Coleoptera)
Blow Fly
Carrion Beetle
Species succession may also provide clues for investigators. Some species may to feed on a fresh corpse, while another species may prefer to feed on one that has been dead for two weeks. Investigators will also find other insect species that prey on the insects feeding on the corpse.
Images: Top Right - Chart -

43. Blow Fly Metamorphosis
Blow flies are attracted to dead bodies and often arrive within minutes of the death of an animal. They have a complete life cycle that consists of egg, larva, pupa, and adult stages.
1st – Adult flies lay eggs on the carcass especially at wound areas or around the openings in the body such as the nose, eyes, ears, anus, etc.
2nd – Eggs hatch into larva (maggots) in hours.
3rd– Larvae continue to grow and molt (shed their exoskeletons) as they pass through the various instar stages.
1st Instar - 5 mm long after 1.8 days
2nd Instar - 10 mm long after 2.5 days
3rd Instar – mm long after 4-5 days
4th – The larvae (17 mm) develop into pupa after burrowing in surrounding soil.
5th – Adult flies emerge from pupa cases after 6-8 days.
Adult
Pupa
Eggs
3rd Instar Larva
1st Instar Larva
2nd Instar Larva
It takes approximately days from egg to adult depending on the temperatures and humidity levels at the location of the body.
Image:
Information: and

44. Examples of Diptera (Flies)
Early Stage Decomposition
Blow & Greenbottle Flies
(Calliphoridae)
Metallic thorax and abdomen
Flesh Fly
(Sarcophagidae) Striped thorax
Life Cycle of a Calliphoridae Fly
Late Stage Decomposition
House Fly
(Muscidae)
Cheese Skipper
(Piophilidae)
Informational Source: Images: Top Left - Middle-Left: Top Right - Bottom -

45. Examples of Coleoptera (Beetles)
Early Stage Decomposition
Early to Late Stage Decomposition
Rove Beetles
(Staphylinidae)
Predator of fly eggs
Clown Beetles
(Histeridae)
Predator of fly eggs
Carrion Beetles (Silphidae) Adults & larvae feed on fly larvae
Late Stage Decomposition
Ham & Checkered Beetles (Cleridae) Predator of flies & beetles;
also feed on dead tissue
Hide Beetles (Scarabidae) Usually the last to arrive
Skin Beetles (Dermestidae) Feed on dried skin & tissues
Informational Source:
Images: &

46. Factors affecting Fly Activity and Oviposition (laying of eggs)
If the body is protected from flies by enclosure such as a car trunk.
If there is a large larval mass causing increased rate of decomposition
If two or more species have colonized the same body
Flies are generally inactive at night and during rain
Time of year: some are active in spring, some fall, some year round

47. Click the image to view a video about the Body Farm!
Weather data is also an important tool in analyzing insect evidence from a corpse. Investigators will make note of the temperature of the air, ground surface, the interface area between the body and the ground, and the soil under the body as well as the temperature inside any maggot masses. They will also collect weather data related to daily temperature (highs/lows) and precipitation for a period of time before the body was discovered to the time the insect evidence was collected.
Other factors that might affect their PMI estimates:
Was the body enclosed in an area or wrapped in a material that would have prevented flies from finding the corpse and laying eggs?
Were other insect species present that may have affected the development of the collected species?
Were there drugs or other poisons in or on the body that might have affected the larvae’s development?
Did you know…
The “Body Farm” in Knoxville, Tennessee is a university research facility to investigate human decomposition under various conditions in order to understand the factors which affect its rate.
Click the image to view a video about the Body Farm!

48. Video links

49. Let’s give it a try …
Click the image above or click here to visit the website at