Estimating Time of Death

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 Body on back – lividity along back and buttocks • 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 3rdinstar Pupa 2ndinstar Adult egg 1stinstar

23. Blowfly Life Cycle – pictures

24. 1stinstar Adult Pupa 2ndinstar Egg 3rdinstar

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 YES! …it’s very complicated Whaaaat?!?

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