2. Bugs Don’t Lie July 9, 1997 Champaign County, Ohio
Stepfather, Kevin Neal, claims stepchildren are missing from their back yard
Bodies discovered on September 6th were in the late stages of decomposition
Autopsies revealed
Maggot infestation
Absence of blowflies and screwworms
Presence of cheese skipper fly in its 3rd instar stage
How were these insects evaluated?
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

3. After Death
As the body decays, odors attract insects to the dead body.
The flies are the first to arrive. Blowflies and flesh flies are flesh feeders and will be the first in line.
If no trauma is present on the body, female blowflies will lay eggs in exposed body openings.

4. Estimating Time of Death
Factors affecting insect development
Temperature
Wind
Time of day
Season
Exposure to elements
Estimation of time of death obtained by raising insects from scene in same conditions at lab.
Process is known as Accumulated Degree Hours (ADH)
scienceinschool.org

5. Time of Death - Insects
Blowfly eggs can be found in the moist, warm areas of a corpse within 8 hours after death.
They will have progressed to the 1st of their 3 larva stages within 20 hours.
By the 4th or 5th day they will have progressed to the 3rd of their 3 larva stages.

6. Time of Death - Insects
By the 8th or 12th day the larvae will migrate away from the corpse to a dry place.
Becoming pupa and immobile within days, they will change from white to dark brown.
By the 21st-24th day the pupa cases will split open and adult blowflies will emerge.

7. Forensic Science: Fundamentals & Investigations, Chapter 11
Image:

8. Phormia regina
Spiracles are incomplete
Third-instar larvae

9. Phaenicia sp
Spiracles are complete
Third-instar larvae

10. Postmortem Interval - PMI
Postmortem Interval- the time elapsed since a person died
When longer than 72 hours after death, entomology becomes important
Within 48 hours the female blowfly lays eggs in moist areas of the body
Forensic Science II: Forensic Entomology, Chapter 12
© 2012 Cengage Learning. All Rights Reserved

11. Postmortem Interval - PMI
Forensic Entomology is used to determine time since death (the time between death and corpse discovery)
This is called postmortem interval or PMI.
scienceinschool.org

12. Postmortem Interval - PMI
Entomological evidence collection
Identify the species
Document larvae length
Determine the instar
Determine PMI
documentingreality.com

13. Collecting & Preserving Evidence
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

14. Collecting & Preserving Evidence
Capture 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

15. 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

16. Forensic Science: Fundamentals & Investigations, Chapter 11

17. Applications Time of injury vs. death Estimation of time of death
Whether or not a corpse has been moved
Instances of insects as weapons
Child and elderly abuse and neglect
Single vehicle car accidents

18. Applications “Roach Track” Confusion
Roaches are notorious for confusing blood spatter analysis
Blood trajectory is often critical to forensic investigations
Roaches, silverfish and other household insects often travel through bloodstained areas

19. Applications: Insects and Illegal Drugs
Shipments of illegal drugs often contain insect infestations, especially cannabis and heroine (derived from poppy plants.)
Analysis of insect “stowaways” can allow investigators to track country of origin, and in many cases the local area of cultivation.
PMI used to detect illegal drugs/poisons in fly larvae (consumed from corpses)