Chapter 11 Death: Meaning, Manner, Mechanism, Cause, and Time By the end f this chapter yu will be able t: Discuss the definitin f death Distinguish between fur manners f death: natural, accidental, suicidal, and hmicidal Distinguish between cause, manner, and mechanisms f death Explain the develpment f rigr, algr, and livr mrtis fllwing death 1 All Rights Reserved Suth-Western / Cengage Learning 2012, 2009 Frensic Science: Fundamentals & Investigatins, Chapter 11
Chapter 11 Death: Meaning, Manner, Mechanism, Cause, and Time By the end f this chapter yu will be able t: 2 Estimate the time f death Describe the stages f decmpsitin f a crpse Use evidence n stmach cntents t estimate time f death Use insect evidence t estimate time f death Explain hw envirnmental factrs can affect the estimated time f death Frensic Science: Fundamentals & Investigatins, Chapter 11
Definitin f Death Cessatin, r end, f life Irreversible cessatin f bld circulatin Cessatin f all brain activity Experts d nt agree n a single definitin 3 Frensic Science: Fundamentals & Investigatins, Chapter 11
Intrductin Autlysis cell death 4 Frensic Science: Fundamentals & Investigatins, Chapter 11
The Manner f Death The manner f death can be 1) Natural, the mst cmmn 2) Accidental 3) Suicidal 4) Hmicidal 5) Undetermined Smetimes the manner f death is difficult t determine 5 Frensic Science: Fundamentals & Investigatins, Chapter 11
Cause and Mechanism f Death Cause f the death Mechanism f death is the reasn fr the death is the specific change in the bdy that brught abut the cessatin f life 6 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Livr Mrtis The Leaden-Clr f Death Lividity With decmpsitin, bld seeps dwn and settles in the lwer parts f a bdy Red bld cells turn bluish-purple 7 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Livr Mrtis 8 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Livr Mrtis Lividity begins abut tw hurs after death Disclratin becmes permanent after eight hurs Ambient temperature affects the speed f decmpsitin Psitin can determine the lividity f the bdy during the first eight hurs 9 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Rigr Mrtis The Rigidity f Death Withut xygen in the bld Calcium accumulates in the muscles Muscles stiffen Starts in the head and expands thrughut After abut 15 hurs Muscle fibers begin t disslve Sftening begins 10 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Rigr Mrtis 11 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Rigr Mrtis Live muscle fibers slide back and frth After death, muscle fibers becme lcked in a flexed psitin 12 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Rigr Mrtis Observatin The bdy is at its mst rigid state N visible signs f rigr Stiffness generally disappears Apprx. Time Scale Just ver 2 hurs Less than 2 hurs r mre than 48 hurs ag After 36 hurs 13 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Rigr Mrtis Factrs affecting rigr mrtis: 1) Ambient temperature 2) Weight f the bdy 3) Type f clthing, r lack f it 4) General health f persn at time f death 5) Level f physical activity at time f death 6) Sun expsure 14 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Algr Mrtis The Chill f Death Bdy heat falls after death Abut 1.5 degrees per hur immediately after death Slwing t less than 1.0 degree per hur after abut 12 hurs Heat lss is affected by the ambient temperature Crpse temperature is measured by a thermmeter inserted int the liver Time f death is expressed as a range f time 15 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Stmach and Intestinal Cntents 16 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Stmach and Intestinal Cntents State f Cntents Undigested fd present in the stmach Stmach is empty, but fd fund in small intestine Small intestine is empty; waste fund in large intestine Timing f Death Zer t tw hurs after the last meal Death ccurred at least fur t six hurs after a meal Death ccurred 12 r mre hurs after a meal 17 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Stages f Decmpsitin Decmpsitin rtting f all tissues and rgans 18 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Stages f Decmpsitin 1) Within tw days f death: 2) After fur days: 3) Within six t ten days: 19 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Stages f Decmpsitin 1) Within tw days f death: cell autlysis begins green and purplish staining ccurs frm bld decmpsitin face becmes disclred 20 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Stages f Decmpsitin 2) After fur days skin blisters abdmen swells with CO₂ that is released by bacteria in the intestines 21 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Stages f Decmpsitin 3) Within six t ten days crpse cntinues t blat as bacteria cntinue t feed n tissues; eventually chest and abdmen will burst fluids begin t leak frm bdy penings eyeballs and ther tissues liquefy 22 skin slughs ff Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Insects Frensic entmlgist Cllects insect evidence frm n, abve, and belw the bdy Recrds envirnmental cnditins Within minutes f a death, certain insects arrive t lay their eggs n the warm bdy blwflies As the crpse decmpses, ther kinds f insects arrive 23 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Insects The insect life cycle prvides scientists with a benchmark t estimate a time f death Insect evidence cannt prvide an exact time f death fluctuating envirnmental cnditins Insect evidence prvides a clse estimate 24 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Blwfly Life Cycle 1. <8 hurs after death blwfly eggs can be fund in the mist, warm areas f a crpse 2. Within 20 hurs 1 st f their 3 larva stages 3. Within 2.5 days 2nd f their 3 larva stages 4. 4 th r 5 th day 3 rd f their 3 larva stages 25 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Blwfly Life Cycle 5. 8 t 12 days larvae migrates t a dry place 6. 18 t 24 days Early pupa; immbile; changes frm light brwn t dark brwn 7. By the 21 st -24 th day the pupa cases will split pen and adult blwflies will emerge. 26 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Blwfly Life Cycle 27 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Blwfly Life Cycle 28 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Blwfly Life Cycle 29 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Blwfly Life Cycle 30 Frensic Science: Fundamentals & Investigatins, Chapter 11
Time f Death Blwfly Life Cycle 31 Frensic Science: Fundamentals & Investigatins, Chapter 11
................. Summary Several definitins f death A bdy decmpsing thrugh three stages livr, rigr, and algr mrtis prvides an estimated time f death Stmach cntents and insect evidence als aid in estimating the time f death Envirnmental factrs affect the estimated time f death 32 Frensic Science: Fundamentals & Investigatins, Chapter 11