1. ESTIMATING TIME OF DEATH

2. So…  Suspects can be eliminated and focus can be put on others  What can be used? 

3. Defining Time of Death  Estimated –  Legal –  Physiological –

4. Time of death continued…  Many deaths are not witnessed – occur in sleep, accidental, suicidal, homicide  Example:  If a serial killer kills a victim in July, but body isn’t found until October  What is the time of death? Physiological – took place in July Legal – October Estimated – could be July, or June or August?

5. Measuring Body Temperature  Normal temp is _?_ degrees Fahrenheit  Body loses heat at a rate of _?_ degrees per hour  Eventually reaches _?_– the temperature of its surroundings  Varies depending on ? ? ?

6. Body temperature continued…  ?_ – reflects true core body temperature  What affects body temperature?     

7. Rigor Mortis   Production of ATP depends on supply of oxygen and nutrients ATP is needed to pull the actin & myosin fibers of the muscle apart; therefore, without oxygen, muscles remain contracted  Lost when heart stops  Causes muscles to _?_  Rigor mortis ends when tissue begins to ?

8. @ Temp of 70 degrees F  _________after death rigor mortis is detectable  Entire process takes _____________to peak  After _?_ hours all muscles relax  Least effective method of determining time of death because it is extremely variable

9. Fun Fact: Cadaveric Spasm  Instantaneous onset of stiffness in the body  Locked in exact posture it was in moment of death  examples?

10. Lividity  Dark, purplish discoloration  Can help determine time of death, and if body was moved 

11. Lividity continued  Color provides clues  Caused by carbon monoxide or cyanide poisoning, or cold temperatures  Severe heart failure, shock, or asphyxia  Example of how it’s used…  Begins ? Hours after death  Becomes permanent _?_ hours after death

12. 2 processes – Decomposition   _?_ – enzymes of body begin a chemical breakdown of cells and tissue   Bacteria destroy the body’s tissue Bacteria of intestinal tract and some environmental bacteria Thrive in warm & moist environments Freezing – stops activities of bacteria

13. Putrefaction is ugly & unpleasant  After 36 hours abdomen, neck, shoulders, and head take on a greenish color  Bloating – accumulation of gas from bacteria – begins in face  Skin develops blisters where liquid or serum accumulate  Skin begins to marble – reveals web-like pattern of blood vessels  Abdomen swells, skin continues to blister. Skin and hair begin to slip from body and fingernails start to slough off  Body turns a greenish-black and fluids of decomposition leave through mouth and nose.  As body swells tissues break open releasing gas and decomposition fluids

14. Rate of Decomposition  Location of body is important:  1 week exposed above ground 

15. Estimating time of death  After a few weeks can be extremely difficult  Body temperature, rigor mortis, lividity no longer are of any use  Postmortem decay timeline is modified according to conditions

16. Other possibilities  Mummification  Bacteria can’t live in dry environments  Egyptians used _? to speed drying process so that bodies wouldn’t decay  Remain in tact for long periods of time so estimating time of death is difficult, if not impossible

18. Sinkers to floaters  Body’s dumped in water:   Rise to surface when gases accumulate because of putrefaction Temperature of water greatly impacts process  Warmer water will float after a few days, cooler water may take weeks or months

19. Bodies found in water display:  Swollen hands and face  Separation of skin from the body  Loss of fingernails after  Floating after 8-10 days in warm water and 2-3 weeks in cold water

20. Stomach contents  Contents of victims stomach help determine T.O.D   Food is undigested – death occurred within 1-2 hours of eating  If stomach is empty – death likely occurred several hours after eating Also, varies between people

21. Getting Buggy…  Bugs usually predictable…But depends on geographic region, locale, time of day, & season  Ex: Blowfly  Nose, mouth, armpit, groin and open wounds favored  Eggs hatch to larvae (maggots) with 24 hours  Within 12 days adult flies emerge

22. Blowfly Life Cycle egg 1 st instar 2 nd instar 3 rd instar Pupa Adult

23. Blowfly Life Cycle – pictures

24. 1 st instar 2 nd instar 3 rd instar Egg Adult Pupa

25. How can this be used?  Find only eggs –  Fully grown maggots, but no pupae – death occurred less than 10 days earlier  Finding pupa indicates that 6-10 days have passed  Circumstances can throw off this schedule:   Extremely cold conditions – may go dormant Ex: if body is warm during day and cool at night maggots may go through lifecycle during the hot times Entomologist may consult climotologist

26. What if someone is dead for 3 weeks?  Why would this be complicated?  Adults produced after ~2 weeks  SO – corpse may have eggs, maggots, pupae, and adult blowflies present Whaaaat?!? YES! …it’s very complicated

27. Other evidence to estimate T.O.D  Broken watch  Victim who missed work for 2 days and is found near his or her front door, dressed in work attire, holding keys, probably heading to work at time of death  Victim never showed for a scheduled racquetball game and was found in the garage in exercise clothes likely died while leaving for game

28. Conclusion 