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:
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.
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
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
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
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
Who is the most notorious serial killer to have never been brought to justice?
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?
Each new murder was more gruesome and violent than the previous one. All five women killed within 1/4 of a mile.
There are many theories about the true identity of Jack the Ripper, his actions, and behavior. Let’s discuss some of these theories now.
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.
Jack the Ripper Part I 4nLOM 4nLOM
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?
424 deg – hours _____________ = Eclosion time Enviro Temp Solve for Enviro Temp. 424 deg-hours Enviro Temp = ____________ = 18.4 deg C 23 hours
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)
Stages 1. Egg 2 – 4. Larva 5. Pupa 6. Adult
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
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
The Diary of Jack the Ripper Part II Complete the question set. WtcsAnU WtcsAnU
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.
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
1.4. 2.5. 3.
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
ND9bNA ND9bNA Decomposition of a Pig 6gNmhr0 6gNmhr0
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
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
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
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
Pay careful attention to the timeline of events and the evidence presented to you. Complete the question set. WtcsAnU WtcsAnU
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