DEATH BUGS AND BONES 1 DEATH MEANING MANNER

DEATH, BUGS, AND BONES 1

DEATH: MEANING, MANNER, MECHANISM, CAUSE, AND TIME BY THE END OF THIS CHAPTER YOU WILL BE ABLE TO: Discuss the definition of death Distinguish between four manners of death: natural, accidental, suicidal, and homicidal Distinguish between cause, manner, and mechanisms of death Explain the development of rigor, algor, and livor mortis following death All Rights Reserved South-Western / Cengage Learning © 2012, 2009 FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 2

DEATH: MEANING, MANNER, MECHANISM, CAUSE, AND TIME BY THE END OF THIS CHAPTER YOU WILL BE ABLE TO: Estimate the time of death Describe the stages of decomposition of a corpse 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 FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 3

DEFINITION OF DEATH 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 4

CELL DEATH Once cell death has occurred Autolysis—cell breakdown – begins If enough cells die the body cannot restart itself and death will occur FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 5

SUSPICIOUS DEATH Autopsy will be conducted if the death is suspicious or was the result of crime. During the autopsy the pathologist will try to determine: Manner of death Cause of death Mechanism of death Time of death FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 6

THE MANNER OF DEATH The manner of death can be Natural, the most common Accidental Suicidal Homicidal Undetermined Sometimes the manner of death is difficult to determine FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 7

HOW SHOULD DEATH BE DETERMINED? • A man with a heart condition is attacked and dies from a heart attack during the assault. Accidental or Homicide? • An elderly woman dies after being kept from receiving proper health care by her son. Natural death or Homicide? FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 8

Both would be considered homicidal, because death resulted during the act of a crime for the man and due to negligence for the woman. Could you convince a jury that it was due to homicide? FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 9

CAUSE AND MECHANISM OF DEATH Cause of the death is the reason for the death Mechanism of death is the specific change in the body that brought about the cessation of life FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 10

HOW TO DETERMINE TIME OF DEATH Livor Mortis Rigor Mortis Algor Mortis Will give a range for time of death, but will not give the exact time. FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 11

TIME OF DEATH—LIVOR MORTIS The Leaden-Color of Death Lividity—With decomposition, blood seeps down and settles in the lower parts of a body Red blood cells turn bluish-purple The discoloration is due to the pooling of blood lividity FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 12

TIME OF DEATH—LIVOR MORTIS 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 FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 13

TIME OF DEATH—RIGOR MORTIS The Rigidity of Death Without oxygen in the blood— Calcium accumulates in the muscles Muscles stiffen Starts in the head and expands throughout After about 15 hours— Muscle fibers begin to dissolve Softening begins FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 14

TIME OF DEATH—RIGOR MORTIS Live muscle fibers slide back and forth After death, muscle fibers become locked in a flexed position FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 15

TIME OF DEATH—RIGOR MORTIS Observation Approx. Time Scale The body is at its most rigid state Just over 12 hours No visible signs of rigor Less than 2 hours or more than 48 hours ago Stiffness generally disappears After 36 hours FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 16

TIME OF DEATH—RIGOR MORTIS Factors affecting rigor mortis: Ambient temperature Weight of the body Type of clothing, or lack of it General health of person at time of death Level of physical activity at time of death Sun exposure FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 17

TIME OF DEATH—ALGOR MORTIS The Chill of Death Body heat falls after death About 1. 5 degrees Fahrenheit per hour immediately after death Slowing to less than 1. 0ºF per hour after about 12 hours Heat loss is affected by the ambient temperature Corpse temperature is measured by a thermometer inserted into the liver Time of death is expressed as a range of time FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 18

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 Death occurred 12 or more hours after a meal FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 19

TIME OF DEATH —Stomach and Intestinal Contents FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 20

CHANGES OF THE EYE During life surface of eye is wet due to blinking Upon death the eye begins to dry out a film forms on surface If eye open – film forms within 2 -3 hrs If eye closed – film forms within 24 hrs After death potassium begins to accumulate in the vitreous humor – rate of accumulation can help predict time of death FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 21

CHANGES IN THE EYE Petechiae - red splotches in the whites of the eye and under the lids of the eye due to the breaking of capullaries. Usually seen on victims of strangulation. FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 22

STAGES OF DECAY Stage What Happens During Decomposition Initial Decay < 2 days Corpse appears normal on outside, but decay is beginning on inside due to bacteria Skin begins to look marbled Face becomes discolored Putrefaction 3 -5 days Odor of decaying flesh is present Corpse appears swollen due to production of CO 2 Skin begins to blister Black Putrefaction 6 -10 Days Very strong odor. Parts of flesh appear black. Body continues to bloat until bursting & gases escape and corpse collapses. Fluids begin to leak out. FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 23

STAGES OF DECAY Stage What Happens During Decomposition Butyric Fermentation > 11 days Corpse is beginning to dry out. Most of flesh is gone Dry Decay >11 days Corpse almost dry. Further decay is slowed due to the lack of moisture FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 24

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 25

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TIME OF DEATH—INSECTS Forensic entomologist Collects insect evidence from on, above, and below the body Records environmental conditions 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 27

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 FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 28

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. FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 29

SPIRACLE SLITS FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 30

TIME OF DEATH—INSECTS 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 31

FORENSIC SCIENCE: FUNDAMENTALS & INVESTIGATIONS, CHAPTER 11 32

. . . . SUMMARY 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 33