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FORENSIC ENTOMOLOGY.  The study of insects and their relationship to time of death.  commonly called upon to determine the postmortem interval or "time.

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Presentation on theme: "FORENSIC ENTOMOLOGY.  The study of insects and their relationship to time of death.  commonly called upon to determine the postmortem interval or "time."— Presentation transcript:

1 FORENSIC ENTOMOLOGY

2  The study of insects and their relationship to time of death.  commonly called upon to determine the postmortem interval or "time since death" in homicide investigations.

3  based on the age of the insect present "Time Since Colonization"  number of different techniques species succession larval weight larval length accumulated degree hour technique

4  Technique used to determine Eclosion period of time it takes an insect to hatch from a fresh egg.  Eclosion times have been tabulated to complete this development in various insect species.  In a blow fly, this time has been determined to be 21.2 hours  ADH = Temperature in C x Eclosion of species

5  Based on a mean temperature of 20 degrees C  For a blow fly ADH = 20 deg C x 21.2 hours Average ADH = 424 degree hours for a blow fly to emerge from its egg For a specific environmental temperature  ADH is divided by the temperature

6  For a specific environmental temperature  Average ADH is divided by the temperature  At 25 degrees C  424 hours / 25 = 17 hours  Eclosion of a blow fly at 25 C = 17 hours

7  Who is the most notorious serial killer to have never been brought to justice?

8  Jack the Ripper  Brutally murdered 5 women from Aug 31 to Nov 9 of 1888 in Whitechapel, London. Mary Ann Nichols, Annie Chapman, Elizabeth Stride, Catherine Eddowes and Mary Jane Kelly  Following the 5 th murder, the killings stopped as suddenly as they began.  The question remains: Who was Jack the Ripper?

9  Each new murder was more gruesome and violent than the previous one.  All five women killed within 1/4 of a mile.

10  There are many theories about the true identity of Jack the Ripper, his actions, and behavior.  Let’s discuss some of these theories now.

11  He was a doctor, in the military, or a butcher.  He removed various organs and other body parts from his victims.  He was a psychopath.  They were revenge killings.

12  Jack the Ripper Part I  4nLOM 4nLOM

13  Eclosion for a black blow fly has been determined to be 23 hours. An average ADH for this insect is 424 degree – hours.  What was the environmental temperature of the crime scene where these insects were collected?  Would you expect the temperature to higher or lower than 20 degrees C? WHY?

14 424 deg – hours _____________ = Eclosion time Enviro Temp  Solve for Enviro Temp. 424 deg-hours Enviro Temp = ____________ = 18.4 deg C 23 hours

15  Blow Flies are most commonly the first insects to infest a dead body.  Lay eggs around natural body orifices Nose Eyes Ears Anus Penis Vagina Open Wounds (Gun shot, Stab, Puncture wounds)

16  Stages 1. Egg 2 – 4. Larva 5. Pupa 6. Adult

17  1 St Stage  Eggs  2 Nd Stage  First Stage Larva hatch from eggs Maggots feed on dead tissue.  3 rd Stage  Second Stage Larva Molts from first stage larva  4 th Stage  Third Stage Larva Molts from second stage larva Masses of third stage maggots produce enough thermal energy to increase ambient temperature up to 10 deg C

18  5th Stage  Third stage Larva molts into Pupa  6th Stage  Pupa develops into adult fly  Approximately 2 weeks from egg to adult  Depends on species and environmental conditions Temperature/Exposure/Humidity

19  The Diary of Jack the Ripper Part II  Complete the question set.  WtcsAnU WtcsAnU

20  Insects will immediately colonize a body. Bacteria, Fungi, and animals Depends upon where the body is located Environmental conditions Some insects thrive in the sun vs. shady conditions  Also dependent upon stage of decomposition Beetles will consume bone and cartilage  Leakage of body fluids will lead to the disappearance of some insects and the appearance of others.

21  1. Fresh Stage – blow flies Ants  2. Bloated Stage – putrefaction begins Rove beetles and Carrion beetles  3. Active Decay Stage Maggots feed around natural orifices of body  4. Advanced Decay Stage Beetles  5. Dry Stage Centipedes, millipedes, cockroaches

22  1.4.  2.5.  3.

23  Objective: Describe the steps used to collect insects from a crime scene.  1. Question of the Day  2. Hand in “Missing Children” Summary  3. Collection of Insects and Applications  4. Jack the Ripper Case Study

24  ND9bNA ND9bNA  Decomposition of a Pig  6gNmhr0 6gNmhr0

25  1. Look at fauna and test soil to see if body has been moved.  2. Collect specimens from different areas of the body, clothing, surrounding environment (indoor/outdoor)  3. Collect 100 maggots  4. Collect pupae from body, clothing, hair, soil  5. Collect empty pupal cases from body, clothing, and surroundings

26  6. Collect adult flies  7. Collect beetles  8. Collect any other insects at scene  9. Collect leaf litter near remains of body if outdoors (enough to fill a coffee can).  10. Place all insects in vials with food

27  Keep insects collected from different parts of the body separate from one another.  Insects would not be present if the body is wrapped in plastic, buried deep underground, and frozen or freezing temperature/conditions

28  Detection of abuse in children  Neglect in the elderly  Automobile/Aircraft accident studies  Interpretation of blood spatter patterns  Determination of time of death  Recovery of human blood from digestive tract  Toxicological analysis

29  Pay careful attention to the timeline of events and the evidence presented to you.  Complete the question set.  WtcsAnU WtcsAnU

30  Insects theorized to be within the top 20 causes of automobile accidents What evidence would support this statement? Consider an automobile accident.  Examination of the fragmented remains of insects that have impacted and lodged onto the front fascia, windshield, and radiator of automobiles.  Yields evidence to the probable path of an automobile through particular areas Pinpointing the location and areas of travel are of unique importance in some investigations

31  Jack the Ripper Part III  gcwpA gcwpA

32  czAcRBY czAcRBY


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