1. Collecting & Preserving Evidence (Obj 12.6, 12.7, 12.8)
Observe and record all pertinent factors
Weather patterns (rainfall, wind, humidity, temperature, and exposure to light) during the PMI
Avoid disturbing insects within several feet of the body
Measure distance from body to insects
Collect samples of all insect stages on, near, and under the body
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

2. Collecting & Preserving Evidence (Obj 12.6, 12.7, 12.8)
1. Estimates on the types and number of insects
2. Key insect colonizations on and near the body
3. Exact positioning of the body using fixed points, if possible: placement of the arms and legs, the position of the head, and parts of the body in the shade and in the sunlight
4. Locations of eggs, larvae, and pupae on the body
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

3. Collecting & Preserving Evidence (Obj 12.6, 12.7, 12.8)
5. List of opportunistic feeders and other insects (such rove beetles, ants, wasps, and insect parasites)
6. Insect movements (within 20 feet of the body)
7. Natural and artificial influences that might affect the speed of decomposition, such as burning, covering, or burying the body
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

4. Collecting & Preserving Evidence
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

5. Factors Affecting Insect Activity
Natural environment and natural light
Natural environment and artificial light
Artificial environment and natural light
Artificial environment and artificial light
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

6. Temperature Readings Ambient air Ground Soil
1 foot above the body
4 feet above the body
Ground Soil
Surface
10 centimeters below
20 centimeters below
Center of a large infestation (if present)
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

7. More on Collecting and Preserving
Capturing live flies with nets
Pin flies to a board, or
Preserve with 80% alcohol and 20% water
Adult flies
Eggs
Largest larvae
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

8. More on Collecting and Preserving
Label vials with
case number
collection time
date
geographic location
the location of the insects on the victim
the initials of the investigator
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

9. Accuracy
Insects begin colonizing at a dead body immediately after death
Dependent on season and environment
Rate of development of the species can be used to estimate time since death
Can give an estimate up to a year

10. Accuracy
Entomological evidence is the most accurate and frequently the only method available to determine the elapsed time since death
Due to rigor, algor, and livor mortis being useless after 72 hours

11. Accuracy Insects are also used to
Determine whether the body has been moved after death
Determine whether it has been disturbed
Determine the presence or position of wound sites
Determine whether the victim used drugs or was poisoned
Determine the length of time of neglect or abuse in living victims

12. Insect Biology
Insects are the most diverse and abundant forms of life on earth.
There are over a million described species- more than 2/3 of all known organisms
There is more total biomass of insects than of humans.
Insects undergo either incomplete or complete metamorphosis (Egg to larva to pupa to insect)
Larva have a soft tubular body and look like worms. Fly species larvae are “maggots”

13. Image: http://www.nlm.nih.gov/visibleproofs