Test 2 Estimating the time since death

Question 1

Importance of determining the Time of Death (TOD) (2)

Answer 1

1. Identification of the victim
2. Prosecution of perpetrator

Question 2

Techniques used (3)

Answer 2

1. Livor mortis
2. Algor mortis
3. Rigor mortis

Question 3

Livor mortis

Answer 3

Color of the body and where the blood settle tells the position in which the body was disposed
- Visible 2 hours after death
- Most visible btw 8-12 hours

Question 4

Algor mortis

Answer 4

Cooling off of the body after death
- Starts shortly following death
- Lasts 8-36 hours after death

Question 5

Rigor mortis

Answer 5

Stiffening of the body
- Starts 2-6 hours after death
- Can last 24-84 hours after death

Question 6

Forensic Taphonomy

Answer 6

A multi-disciplinary study of the stages through which the human body goes from being fresh to being completely skeletonized

Question 7

Stages of Decomposition

Answer 7

1. Autolysis
2. Putrefaction

Question 8

Autolysis

Answer 8

Liquid used for digestion. Digest the body/organs when death occurs

Question 9

Putrefaction

Answer 9

• When micro-organisms normally residing in the body tissues begin to proliferate (increase rapidly) and breakdown biological components-> eat the soft tissues
• Because they are no longer fought by the body’s defense system

Question 10

Elements that may accelerate/slow down the process of decomposition (6)

Answer 10

1. Insect activity +
2. Animal scavenging +
3. Presence of plants +
4. Environment
5. Climate
6. Accessibility- To all the previous-> +

Question 11

Post mortem Intervals (7)

Answer 11

1. Surface remains
2. Buried/Submerged remains
3. Animal scavenging
4. Forensic Entomology
5. Forensic Botany
6. Deterioration of clothing
7. Body fluids

Question 11

Surface remains

Answer 11

Time of decomposition varies with types of climate
- Warm and moist (Tennessee) = Fastest
- Hot and dry (Arizona) = Mild
- Cold climates (Canada) = Slowest

Question 12

Buried/Submerged remains

Answer 12

1 week on the surface = 2 weeks in the water = 8 weeks underground
(General observation needs to be more thoroughly investigated)

Question 13

Animal Scavenging

Answer 13

-If only 20% of bones are found = a post-mortem interval of more than 6 months is indicated
-If 80% of the bones are found, a post-mortem interval of less than 6 months is indicated
(General observation needs to be more thoroughly investigated)

Question 14

Forensic Entomology

Answer 14

1. Life cycle of flies
2. Succession of insects

Question 15

Life cycle of flies

Answer 15

• Within minutes after death: Flies colonize the body and females begin laying eggs
• Between 6-40 hours: Eggs hatch into larvae/maggots and begin to feed on the body
• Between 3-10 days: Larvae migrate off of the body and bury themselves into the ground near the remains
• Between 6-18 days: Larvae emerge out of the ground as adult flies and return to the body.
  -> Cycle of life repeats

Question 16

Succession of insects

Answer 16

• <3days = only flies
• Between 3-13 days: Mostly flies and some beetles
• Between 13-25 days: Flies and Beetles relatively to an equal
• > 25 days = Mostly only beetles
  *Insect activity may be affected by the climate and environment

Question 17

Forensic Botany

Answer 17

Amount of plant growth beneath a surface body:
- None = < 1yr
- More compared to surroundings = > 1yr
Growth rate of vegetation:
- Ex: 1 ring in a tree= 1 yr of life-> if a tree went through a body and it has 5 rings = body is at least 6 yrs old

Question 18

Deterioration of clothing

Answer 18

• Organic material deteriorates = <1yr
• Acrylic material is a little deteriorated = after 2 yrs
• Polyester material is a little deteriorated = after 4 yrs

Question 19

Body Fluids

Answer 19

Body fluids at different stages of decomposition have different chemical make-up
-> Take a sample of the soil beneath the body to analyze the body fluids