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Chapter 11 Death: Manner,
Mechanism, Cause, and Time
By the end of this chapter you will be able to:
 explain the development of livor, rigor, and algor
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mortis following death
use evidence of these to estimate time of death
use evidence on stomach contents to estimate
time of death
use insect evidence to estimate time of death
explain how environmental factors can affect the
estimated time of death
All Rights Reserved South-Western / Cengage Learning © 2009
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Forensic Science: Fundamentals & Investigations, Chapter 11
Death
The Manner of Death
 The manner of death can be ___________,
_____________, _____________,
____________, or _____________.
 Sometimes it is _____________ to determine
the manner of death.
 The _____________________ manner of
death is ______________.
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Forensic Science: Fundamentals & Investigations, Chapter 11
Death
Cause and Mechanism of Death
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
The reason for the death is the cause of
the death.

The ______________in the body that
brought about the _______________ is
the mechanism of death.
Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Livor Mortis
The Leaden-Color of Death
 When red blood cells break down, they turn a
____________________.
 With decomposition, blood ____________ and
settles in the ______________ of a body.
 The _________________ that accompanies
this becomes permanent after ____ hours.
 _________________ accelerates the process.
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Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Rigor Mortis
The Rigidity of Death
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At death, skeletal muscles ____________ relax.
____________________, _______________ in
these muscles.
The muscles become ____________.
This starts in the ________ and works its way
down to the _______.
After about ___ hours, the muscle fibers begin to
_____________, and ______________ begins.
Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Rigor Mortis
 At _____hours after death, the body is at its _____
rigid state.
 If a body has ____ visible signs of rigor, it probably
has been dead _____ than __ hours or ____ than
___.
 If the body exhibits rigor ____ in the ____ and ____,
the time of death is just over ___ hours.
 This ________ will have disappeared for the most
part after ___ hours.
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Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Rigor Mortis
Many factors affect when rigor mortis sets in and
how long it lasts:
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________________________
________________________
________________________
________________________
________________________
________________________
Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Algor Mortis
The Chill of Death
 In death a body no longer generates _______
and begins to ________ down.
 To find the _________ temperature of a corpse, a
thermometer is inserted into the _______.
 Body heat is lost at about __ to ___ degrees an
______.
 Time of death determined by temperature
calculations is expressed as a ______________.
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Forensic Science: Fundamentals & Investigations, Chapter 11
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. _________________________________
2. _________________________________
3. _________________________________
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Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Stages of
Decomposition
Choose: A. Within 2 days. B. After 4 days. C. Within 6-10 days.
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2.
3.
4.
5.
6.
7.
8.
9.
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Fluids begin to leak from body openings as cell membranes
rupture.
Discoloration of the face.
The skin sloughs off.
The skin blisters.
Green and purplish staining from blood decomposition.
The corpse bloats.
Eyeballs and other tissues liquefy.
The abdomen swells.
Marbling appearance on the skin.
Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Insects
 Besides recording data about the environment
at a crime scene, a
__________________collects insect evidence.
 Within _____________ of a death, certain
insects arrive to lay their eggs on the warm
body. ___________ are a common example.
 As a corpse progresses through the stages of
decomposition, other kinds of insects arrive.
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Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Insects
1. _____________ can be found in the ______,
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_____ areas of a corpse within ___ hours after
death.
2. They will have progressed to the ____ of their
___ larva stages (illustration of one shown
above) within _______ hours.
3. By the ____ or _____ day they will have
progressed to the ____ of their 3 larva stages.
Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Insects
4. By the ___ or ____ day the larvae will migrate
away from the corpse to a _____ place.
5. Becoming ____ and immobile within _____
days, they will change from white to dark
brown.
6. By the ____-____ day the pupa cases will
split open and _________________
(illustration of one shown above) will emerge.
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Forensic Science: Fundamentals & Investigations, Chapter 11
Time of Death—Insects
 Because scientists ________ how long it takes for
the various stages of development at given
temperatures, forensics entomologists can
_______ when the insects arrived.
 Because life cycles are affected by fluctuations in
the daily ____________ conditions, ____________
_______ provide an exact time of death.
 Insect evidence, nonetheless, can yield a close
______________.
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Forensic Science: Fundamentals & Investigations, Chapter 11
What do they do?
_____________________apply their knowledge of entomology to provide
information for criminal investigations.
A forensic entomologist’s job may include:
• Identification of _________ at various stages of their life cycle, such as eggs,
larva, and adults.
• ______________ and ___________ of insects as evidence.
• Determining an estimate for the ____________________or _____ (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.
• _____________ 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
The broad field of forensic entomology is
commonly broken down into three general
areas: _______________, _________, and
______________________________.
The medicolegal section focuses on the
_______________ of the legal system and
deals with the ___________ (or carrion)
feeding insects that typically infest human
remains.
The urban aspect deals with the insects that
__________ and his _________ environment.
How diverse is forensic entomology?
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The diverse applications of forensic entomology
include the detection of ___________ and
___________________.
Published cases exist that detail parents
intentionally using wasps and bees to sting their
children as a form of _________________.
Additionally, entomological evidence has been
used to prove ____________________ for
wounds existing on the elderly under both
private and institutional care.
•
It is theorized that the _________ (or mere
________) of bees and wasps may be
responsible for a __________ number of
__________occupant car accidents that seem to
lack a definitive cause.
•
Some accident studies have shown insects to be
within the top _____ causes of automobile
accidents.
•
In addition to automobile accidents, insects
have been suspected of causing ______ crashes
through the _________ of essential
instrumentation, and even implicated in the
obstruction of ___________ causing engine
failure.
•
Forensic entomologists are also requested to
examine the ________________of insects
that have impacted and lodged on the
______________, ____________, and
______________ of automobiles.
•
Analysis of such remains can yield evidence
to the ____________ path of an automobile
through particular areas when pinpointing
the location and areas of travel are of unique
importance.
•
Insects can also _______ the ____________
of blood spatter pattern analysis.
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Roaches __________________ through
pooled and splattered blood will produce
tracking that may not be readily recognizable
to the untrained observer.
Similarly, flies and fleas may also track
through pooled and spattered
blood. However, flies will also feed on the
blood and then pass the partially digested
blood in its feces, which are known as
“____________________________".
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If a crime occurs in a
_______________________apartment, fecal
drops already present would serve to
confuse analysts as those droplets would
test positive for human blood.
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Therefore it is important to recognize and
__________________ the natural artifacts
that may occur from the presence, feeding,
and defecation of roaches, flies, and fleas.
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Insects that feed on living,
decomposing, or dried vegetable
material are submitted to the forensic
entomologist in an effort to determine
the ____________ or _______________.
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This is particularly important with
vegetative material such as
_________________________.
Insects as Evidence
Forensic entomologists use their knowledge of insects and
their life cycles and behaviors to give them clues about a
crime.
Blow Fly
Most insects used in investigations are in two major orders:
1 – ___________(Diptera) and
2 – ________________ (Coleoptera)
Carrion Beetle
_______________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 - http://www.insectinvestigations.com/aboutfe.htm, Chart - http://www.clt.uwa.edu.au/__data/page/112507/fse07_forensic_entomology.pdf
______________ 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:
1.
Was the body ______________in an area or ___________ in a material that would have
prevented flies from finding the corpse and laying eggs?
2.
Were other _______________________ that may have affected the development of the
collected species?
3.
Were there _____________________________- 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!
Blow Fly Metamorphosis
Blow flies are attracted to dead bodies and often arrive within minutes of the death of an
animal. They have a ________ life cycle that consists of ___, _____, ____, and _____ stages.
1st – Adult flies lay _____ 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 ______ (maggots) in 12-24
hours.
3rd– Larvae continue to grow and______ (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 – 14-16 mm long after 4-5 days
Adult
Pupa
3rd Instar
Larva
2nd Instar
Larva
4th – The larvae (17 mm) develop into pupa after
burrowing in surrounding soil.
5th – _______ flies emerge from pupa cases after 6-8
days.
Eggs
1st
Instar
Larva
It takes approximately 14-16 days from egg to
adult depending on the temperatures and
humidity levels at the location of the body.
Image: http://www.umext.maine.edu/images/FlyLife.jpg
Information: http://www.kathyreichs.com/entomology.htm and http://www.forensicentomologist.org/
Examples of Diptera (Flies)
Early Stage
Decomposition
Blow & Greenbottle Flies
(Calliphoridae)
Flesh Fly
(Sarcophagidae)
Metallic thorax and abdomen
Striped thorax
House Fly
(Muscidae)
Cheese Skipper
(Piophilidae)
Life Cycle of a
Calliphoridae Fly
Late Stage
Decomposition
Informational Source: http://naturalsciences.org/files/documents/csi_tg_overview.doc
Images: Top Left - http://www.scienceinschool.org/repository/images/issue2forensic3_large.jpg, Middle-Left: http://forensicfact.files.wordpress.com/2008/04/blowfly053.jpg,
Top Right - http://users.usachoice.net/~swb/forensics/P1.jpg, Bottom - http://www.deathonline.net/decomposition/corpse_fauna/flies/index.htm
Examples of Coleoptera (Beetles)
Early Stage Decomposition
Carrion Beetles (Silphidae)
Adults & larvae feed on fly larvae
Early to Late Stage Decomposition
Rove Beetles
Clown Beetles
(Staphylinidae)
(Histeridae)
Predator of fly eggs
Predator of fly eggs
Late Stage Decomposition
Ham & Checkered Beetles
(Cleridae)
Predator of flies & beetles;
also feed on dead tissue
Hide Beetles
Skin Beetles (Dermestidae)
(Scarabidae)
Usually the last to arrive
Feed on dried skin & tissues
Informational Source: http://naturalsciences.org/files/documents/csi_tg_overview.doc
Images: http://www.cals.ncsu.edu/course/ent425/library/spotid/coleoptera/coleoptera.html & http://www.forensicflies.com/beetles.htm
Let’s give it a try …
Click the image above or click here to visit the website at
http://www.pbs.org/wnet/nature/episodes/crime-scene-creatures/interactive-determine-the-time-of-death/4390/
. . . . . . . . . . . . . . . . . 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.
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Forensic Science: Fundamentals & Investigations, Chapter 11