Chapter 11 Death Meaning Manner Mechanism Cause and

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Chapter 11 Death: Meaning, Manner, Mechanism, Cause, and Time 1 All Rights Reserved South-Western

Chapter 11 Death: Meaning, Manner, Mechanism, Cause, and Time 1 All Rights Reserved South-Western / Cengage Learning © 2012, 2009

Chapter 11 Death: Meaning, Manner, Mechanism, Cause, and Time By the end of this

Chapter 11 Death: Meaning, Manner, Mechanism, Cause, and Time By the end of this chapter you will be able to: o o 2 Discuss the definition of death Distinguish between five manners of death: natural, accidental, suicidal, homicidal, and undetermined Distinguish between cause, manner, and mechanisms of death Explain the development of rigor, algor, and livor mortis following death Forensic Science: Fundamentals & Investigations, Chapter 11 All Rights Reserved South-Western / Cengage Learning © 2012, 2009

Chapter 11 Death: Meaning, Manner, Mechanism, Cause, and Time By the end of this

Chapter 11 Death: Meaning, Manner, Mechanism, Cause, and Time By the end of this chapter you will be able to: o o o 3 Estimate the time of death Use evidence on stomach contents to estimate time of death Use evidence from the eye to estimate time of death Use insect evidence to estimate time of death Explain how environmental factors can affect the estimated time of death Forensic Science: Fundamentals & Investigations, Chapter 11

Definition of Death o o 4 Cessation, or end, of life Irreversible cessation of

Definition of Death o o 4 Cessation, or end, of life Irreversible cessation of blood circulation Cessation of all brain activity Experts do not agree on a single definition Forensic Science: Fundamentals & Investigations, Chapter 11

The Manner of Death o The manner of death can be Natural, the most

The Manner of Death o The manner of death can be Natural, the most common • Accidental • Suicidal • Homicidal • Undetermined List some examples of each. • o 5 Sometimes the manner of death is difficult to determine Forensic Science: Fundamentals & Investigations, Chapter 11

Cause and Mechanism of Death o o 6 Cause of death is the reason

Cause and Mechanism of Death o o 6 Cause of death is the reason for the death List some causes of death. Forensic Science: Fundamentals & Investigations, Chapter 11

Cause and Mechanism of Death o o 7 Mechanism of death is the specific

Cause and Mechanism of Death o o 7 Mechanism of death is the specific change in the body that brought about the cessation of life List some mechanisms of death. Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Livor Mortis The Leaden-Color of Death o o 8 Lividity—With decomposition, blood

Time of Death—Livor Mortis The Leaden-Color of Death o o 8 Lividity—With decomposition, blood seeps down and settles in the lower parts of a body Red blood cells turn bluish-purple Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Livor Mortis o o o 9 Lividity begins about two hours after

Time of Death—Livor Mortis o o o 9 Lividity begins about two hours after death Discoloration becomes permanent after eight hours Ambient temperature affects the speed of decomposition Lividity can determine the position of the body during the first eight hours Caution: Next photos are REAL. Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Livor Mortis What might cause the uncolored region? 10 Forensic Science: Fundamentals

Time of Death—Livor Mortis What might cause the uncolored region? 10 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Livor Mortis What does this livor mortis tell us? 11 Forensic Science:

Time of Death—Livor Mortis What does this livor mortis tell us? 11 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Livor Mortis What might cause the uncolored region? What does this tell

Time of Death—Livor Mortis What might cause the uncolored region? What does this tell us? 12 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Rigor Mortis The Rigidity of Death o Without oxygen in the blood—

Time of Death—Rigor Mortis The Rigidity of Death o Without oxygen in the blood— • o o Muscles stiffen Starts in the head and expands throughout After about 15 hours— • • Muscle fibers begin to dissolve Softening begins CAUTION: Real photos ahead. 13 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Rigor Mortis The Rigidity of Death 14 Forensic Science: Fundamentals & Investigations,

Time of Death—Rigor Mortis The Rigidity of Death 14 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Rigor Mortis The Rigidity of Death Unnatural position indicates someone moved the

Time of Death—Rigor Mortis The Rigidity of Death Unnatural position indicates someone moved the body 15 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Rigor Mortis Live muscle fibers slide back and forth After death, muscle

Time of Death—Rigor Mortis Live muscle fibers slide back and forth After death, muscle fibers become locked in a flexed position 16 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Rigor Mortis 17 Observation Approx. Time Scale No visible signs of rigor

Time of Death—Rigor Mortis 17 Observation Approx. Time Scale No visible signs of rigor Less than 2 hours or more than 36 hours ago Body at peak of rigor Around 12 hours Stiffness generally disappears After 36 hours Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Rigor Mortis Factors affecting rigor mortis: 18 o Ambient temperature (heat softening)

Time of Death—Rigor Mortis Factors affecting rigor mortis: 18 o Ambient temperature (heat softening) o Weight of the body (heavier o Type of clothing, or lack of it (warm clothing rigor) Forensic Science: Fundamentals & Investigations, Chapter 11 rigor and rigor)

Time of Death—Rigor Mortis Factors affecting rigor mortis: 19 o General health of person

Time of Death—Rigor Mortis Factors affecting rigor mortis: 19 o General health of person at time of death o Level of physical activity at time of death (exercise right before death rigor in the active muscles) o Sun exposure (heat Forensic Science: Fundamentals & Investigations, Chapter 11 )

Time of Death—Algor Mortis The Chill of Death o Body heat falls after death

Time of Death—Algor Mortis The Chill of Death o Body heat falls after death • About 0. 78°C per hour immediately after death • Slowing to less than 0. 39°C per hour after about 12 hours • Heat loss is affected by the ambient temperature 20 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Algor Mortis The Chill of Death o Corpse temperature is measured by

Time of Death—Algor Mortis The Chill of Death o Corpse temperature is measured by a thermometer inserted into the liver o Time of death is expressed as a range of time 21 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death —Stomach and Intestinal Contents State of Contents Timing of Death Undigested

Time of Death —Stomach and Intestinal Contents State of Contents Timing of Death Undigested food present in the stomach Zero to two hours after the last meal Stomach is empty, but food Death occurred at least four found in small intestine to six hours after a meal Small intestine is empty; waste found in large intestine 22 Forensic Science: Fundamentals & Investigations, Chapter 11 Death occurred 12 or more hours after a meal

Time of Death —Stomach and Intestinal Contents 23 Forensic Science: Fundamentals & Investigations, Chapter

Time of Death —Stomach and Intestinal Contents 23 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death —Stages of Decomposition Choose: A. Within 2 days. B. After 4

Time of Death —Stages of Decomposition Choose: A. Within 2 days. B. After 4 days. C. Within 6 -10 days. 1. 2. 3. 4. 5. 6. 7. 8. 9. 24 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 o Forensic entomologist • Collects insect evidence from on, above, and

Time of Death—Insects o Forensic entomologist • Collects insect evidence from on, above, and below the body • Records environmental conditions o o 25 Within minutes of a death, certain insects arrive to lay their eggs on the warm body—blowflies As the corpse decomposes, other kinds of insects arrive Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death —Blowfly Life Cycle 1. <8 hours after death—blowfly eggs can be

Time of Death —Blowfly Life Cycle 1. <8 hours after death—blowfly eggs can be found in the moist, warm areas of a corpse 2. Within 20 hours— 1 st of their 3 larva stages 3. 4 th or 5 th day— 3 rd of their 3 larva stages 26 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death —Blowfly Life Cycle 4. 8 to 12 days—larvae migrates to a

Time of Death —Blowfly Life Cycle 4. 8 to 12 days—larvae migrates to a dry place 5. 18 to 24 days— Early pupa; immobile; changes from light brown to dark brown 6. By the 21 st-24 th day the pupa cases will split open and adult blowflies will emerge. 27 Forensic Science: Fundamentals & Investigations, Chapter 11

Time of Death—Insects o o o 28 The insect life cycle provides scientists with

Time of Death—Insects o o o 28 The insect life cycle provides scientists with a benchmark to estimate a time of death Insect evidence cannot provide an exact time of death—fluctuating environmental conditions Insect evidence provides a close estimate Forensic Science: Fundamentals & Investigations, Chapter 11

. . . . Summary o o 29 Several definitions of death A body

. . . . Summary o o 29 Several definitions of death A body decomposing through three stages— livor, rigor, and algor mortis—provides an estimated time of death Stomach contents and insect evidence also aid in estimating the time of death Environmental factors affect the estimated time of death Forensic Science: Fundamentals & Investigations, Chapter 11