1 Chapter 11 Death use insect evidence to estimate time of death explain how environmental factors...

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Chapter 11 Death

use insect evidence to estimate time of death explain how environmental factors can affect the

estimated time of death Properly i.d. cause, manner & mechanism of deathexplain the development of livor, rigor, and algor

mortis following death use evidence of these to estimate time of death use evidence on stomach contents to estimate time

of death

✓✓

TODAY’S GOALS (2 of em’):

1. Identify the definition of death

2. Demonstrate knowledge of: –cause of death–manner of death–mechanism of death

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THE BIG IDEA

DEATH = the point where resuscitation (bringing back to life ) becomes impossible

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* * * It helps to think of death as a process not an

instant event * * *

Imagine you’re a forensic pathologist

Your job is to identify the following 3 things:

1.Cause of death

2.Manner of death

3.Mechanism of death

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* Depending on your

answers a formal

investigation may be

opened *

In the tune of “Frosty the Snowman” by Walter “Jack” Rollins and Steve Nelson

Cau-ses are e-ventsThe man-ners are short

and sweetMech-an-ism is a body

change Lead-ing you to die5

♪♫

♬♪

♪

Cause of death

C.O.D. = the event that led to someone’s death

- Shark attack- Cancer- Shot

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CHECKING FOR UNDERSTANDING

Gang member shot in a retaliation killing = _________ Failing shop owner with family and life insurance

policy drives off a cliff = ______________ Hospital receives a gun shot victim who survived a

mob hit. Days after he is stabilized the mob returns and suffocates him with a pillow = _____________

Man survives atomic blast. 10 years later he gets cancer and dies = __________

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SHOT

CAR ACCIDENT

SUFFOCATION

Cause of death

CANCER

In the tune of “Frosty the Snowman” by Walter “Jack” Rollins and Steve Nelson

Cau-ses are e-ventsThe man-ners are short

and sweetMech-an-ism is a body

change Lead-ing you to die8

♪♫

♬♪

♪

Manner of death

Manner of death = the short official way a person’s death is described

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5 Manners of Death

CHECKING FOR UNDERSTANDING

80 yr old dies peacefully in her sleep = _________ Gang member dies in a retaliation killing = _________ Failing shop owner with family and life insurance

policy drives off a cliff = __________ 30 years after leaving his family on Christmas eve a

man’s mummified body is found in the chimney wearing Santa suit = _____________

Can’t be determined = _______________

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ACCIDENTAL

NATURAL HOMICIDE

SUICIDE

UNDETERMINED

Manner of death

In the tune of “Frosty the Snowman” by Walter “Jack” Rollins and Steve Nelson

Cau-ses are e-ventsThe man-ners are short

and sweetMech-an-ism is a body

change Lead-ing you to die12

♪♫

♬♪

♪

Mechanism of Death

Mechanism of Death = the physiological change that led to death

- Massive blood loss- Multiple organ failure- Trauma to the brain

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CHECKING FOR UNDERSTANDING

80 yr old dies in her sleep = __________________ Gang member shot = _________________________ Shop owner with life insurance policy drives his car off

a cliff = ________________________________ 30 years after leaving his family on Christmas eve a

man’s mummified body is found in the chimney wearing Santa suit = __________________________

Can’t be determined = _______________

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Stoppage of breathing (asphixia)

multiple organ failure bleed to death (exsanguination)

Trauma to the brain (cerebral contusion)

UNDETERMINED

Mechanism of death

Cause, Manner, & Mechanism Assignment (5 minutes or less)

1. On a new sheet of paper (that will be collected) write your name, date, and period.

2. Neatly create a sentence or two explaining a man’s death. (Using professional language)

3. Switch papers with a neighbor and then print your name at the bottom of their paper.

4. Identify the cause, manner, mechanism of their death story

5. Write a few sentences defending why you answered the way you did (use the word “because”)15

THE BODY IS A CRIME SCENE

Forensic Science: Fundamentals & Investigations, Chapter 11 16

4 WAYS TO UNDERSTAND A BODY AS CRIME SCENE

Livor mortis – – blood settling

Rigor mortis – – muscles stiffening and relaxing

Algor mortis – – Temperature loss

Entimology – – insect life stage

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Livor Mortis Livor – bluish color (Latin) When red blood cells break down, they turn a bluish-

purple. With no circulation, gravity pulls blood down and

settles it in the lower parts of a body. Warmth accelerates the process. L.M. START TO BE VISIBLE 30 MINUTES TO

120 MINUTES AFTER DEATH

L.M. becomes permanent after 8 hours.

Livor mortis

Forensic Science: Fundamentals & Investigations, Chapter 11 19

Livor mortis

Forensic Science: Fundamentals & Investigations, Chapter 11 20

IGNORE THE PILLOWS

This body was found with livor mortis on the top side of the body. What must have happened to allow this?

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Rigor Mortis RIGOR MORTIS = muscle stiffening

and relaxing after death Without oxygen, calcium accumulates

in muscles. As a result, the muscles become stiff. This starts in the small muscles

(head and appendages) and works its way to large muscles (legs).

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Rigor Mortis 2 hours A.D. = rigor begins at small muscles

and moves to larger muscles12 hours A.D. = body is most rigid 15 hours A.D. = rigor begins to relax small

muscles > larger 36 hours A.D. = stiffness will have disappearedIf a body has no visible signs of rigor, it has

been dead less than 2 hours or more than 36.– The state of decay will tell you which is which

RIGOR MORTIS

Forensic Science: Fundamentals & Investigations, Chapter 11 24

AL GORE – TEMP CHANGE

Forensic Science: Fundamentals & Investigations, Chapter 11 25

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Algor MortisAlgor Mortis = coldness of

deathIn death, a body no longer

generates warmth and begins to cool down.

Thermometer is inserted into the liver

Tem

p (

deg

rees

F)

Forensic Science: Fundamentals & Investigations, Chapter 11 27

Time (hours)

DEATH (98º F)

AMBIENT TEMPERATURE

Some factors that affect algor mortis

Weight / insulation of individualClothing layersHumidity / wetness

Forensic Science: Fundamentals & Investigations, Chapter 11 28

Entomology (blow fly)

Egg = 2 mm 1st instar = 5mm 2nd instar = 10mm 3rd instar = 17mm Pupa = 9mm (skin actually shrinks &

hardens)

Adult (crawling) = varies*(Blow flies do not fly much for a day or two while their body is hardening)

Adult (flying) = useless for FS

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Head

Breathing holes

Finishing your cheat sheet timeline

Entomology(BUGS)

Livermortis(BLOOD)

Rigormortis(STIFFNESS)

Algormortis(TEMP)

hrs

days1

st ins

tar

3R

D ins

tar

2N

D inst

ar

AD

ULT

PU

PA

hrs

days

days

days

hrs

hrs

0 1 2 6

24 48

10

star

ts to

be

visi

ble

SE

T IN

B

OD

Y10

10

brea

k

Forensic Science: Fundamentals & Investigations, Chapter 11 31

Time of Death—Stomach and Intestinal Contents

Based on these specifics, give an estimate for each of these on how much time has passed since the meal was eaten: 1. Food is still present in the stomach. 2. The stomach is empty but food is found in

the small intestine. 3. The small intestine is empty but waste is

present in the large intestine.

Forensic Science: Fundamentals & Investigations, Chapter 11 32

Time of Death—Stages of Decomposition

Choose: A. Within 2 days. B. After 4 days. C. Within 6-10 days.

1. Fluids begin to leak from body openings as cell membranes rupture.

2. Discoloration of the face.

3. The skin sloughs off.

4. The skin blisters.

5. Green and purplish staining from blood decomposition.

6. The corpse bloats.

7. Eyeballs and other tissues liquefy.

8. The abdomen swells.

9. Marbling appearance on the skin.

Forensic Science: Fundamentals & Investigations, Chapter 11 33

Time of Death—Insects

Besides recording data about the environment at a crime scene, a forensic entomologist collects insect evidence.

Within minutes of a death, certain insects arrive to lay their eggs on the warm body. Blowflies are a common example.

As a corpse progresses through the stages of decomposition, other kinds of insects arrive.

Forensic Science: Fundamentals & Investigations, Chapter 11 34

Time of Death—Insects

1. Blowfly eggs can be found in the moist, warm areas of a corpse within 8 hours after death.

2. They will have progressed to the 1st of their 3 larva stages (illustration of one shown above) within 20 hours.

3. By the 4th or 5th day they will have progressed to the 3rd of their 3 larva stages.

Forensic Science: Fundamentals & Investigations, Chapter 11 35

Time of Death—Insects

4. By the 8th or 12th day the larvae will migrate away from the corpse to a dry place.

5. Becoming pupa and immobile within 18-24 days, they will change from white to dark brown.

6. By the 21st-24th day the pupa cases will split open and adult blowflies (illustration of one shown above) will emerge.

Forensic Science: Fundamentals & Investigations, Chapter 11 36

Time of Death—Insects

Because scientists know how long it takes for the various stages of development at given temperatures, forensics entomologists can determine when the insects arrived.

Because life cycles are affected by fluctuations in the daily environmental conditions, insect evidence cannot provide an exact time of death.

Insect evidence, nonetheless, can yield a close estimate.

Forensic Science: Fundamentals & Investigations, Chapter 11 37

. . . . . . . . . . . . . . . . . Summary. . . . . . . . . . . . . . . . . Summary

A body decomposes through the 3 changes of livor, rigor, and algor mortis.

Forensic scientists use evidence from these to estimate the time of death.

They also use stomach contents and insect evidence to estimate the time of death.

It is also important to remember how environmental factors can affect the estimated time of death.