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Forensic Entomology. Taxonomy Classification of Things in an Orderly Way We are interested in the phylum, Arthropoda; class, Insecta; order: Diptera (flies)

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Presentation on theme: "Forensic Entomology. Taxonomy Classification of Things in an Orderly Way We are interested in the phylum, Arthropoda; class, Insecta; order: Diptera (flies)"— Presentation transcript:

1 Forensic Entomology

2 Taxonomy Classification of Things in an Orderly Way We are interested in the phylum, Arthropoda; class, Insecta; order: Diptera (flies) Coleoptera (beetles)

3 There are three areas of application: Insect damage to structures Infestation of foodstuffs Insects that inhabit human remains (focus of this chapter) Forensic Entomology Involves the use of insects and other arthropods to aid in legal investigations. Entomology is the study of insects.

4 The Process of Death Algor Mortis: Body cooling rate Hours since death = 98.4°F – internal body temperature 1.5 Livor Mortis: skin discoloration caused by pooling of blood Rigor Mortis: rigidity of skeletal muscles A pathologist estimates time of death from these factors. Temperature of body Stiffness of body Time since death Warm Not stiff Not dead more than 3 hours WarmStiff Dead between 3 and 8 hours ColdStiff Dead between 8 and 36 hours Cold Not stiff Dead for more than 36 hours

5 The Process of Death, continued StageDescription Initial or fresh decay (autolysis) The cadaver appears fresh externally but is decomposing internally due to the activities of bacteria present before death (0–4 days). Putrefaction or bloating The cadaver is swollen by gas produced internally, accompanied by the odor of decaying flesh (4–10 days). Black putrefaction Flesh of creamy consistency, with exposed body parts black. Body collapses as gases escape. Fluids drain from body. Odor of decay very strong (10–20 days). Butyric fermentation Cadaver drying out. Some flesh remains at first; cheesy odor from butyric acid (20–50 days). Dry decay (diagenesis) Cadaver almost dry; slow rate of decay. May mummify (50–365 days).

6 Life Cycle of Insects Metamorphosis egg larva (maggot) pupa winged adult The life cycle of Musca domestica


8 Insects arrive at a decomposing body in a particular order (succession) and then complete their life cycle based on the surrounding temperature. By collecting and studying the types of insects found on a body and their metamorphic stage, a forensic entomologist can estimate the time of death. Time of Death

9 Insects of Death Diptera First to arrive Then Blowflies Flesh flies Houseflies Flies can arrive within minutes. They lay eggs that hatch to maggots. Maggots feed on soft, mushy body parts. More insects arrive to feed on the body and each other.

10 Insects of Death, continued Coleoptera In rough order of appearance, from within hours to dry decay: Rove beetle Sexton beetle Clown beetle Dermestid beetle Hide beetle Some beetles feed on the corpse, some on maggots, some on other beetles.

11 Variables Affecting Metamorphosis Temperature The higher the temperature (within limits), the faster the growth.

12 Variables Affecting Metamorphosis, continued Habitat Fly species can vary geographically according to climate, season, and habitat. For example, the fly pictured on the left prefers shade; the one on the right, sunlit areas. Phormia regina Lucilia illustris

13 Damage to structures, clothing, foodstuffs Location of wounds on a corpse Linking suspect to scene of crime Source of contraband Type of insects can trace vehicle movement Presence of drugs in corpse Other Applications of Forensic Entomology

14 Collection of Evidence

15 Human Remains 15 Human Remains

16 16 Forensic Anthropology Forensic anthropology is a type of applied anthropology that specializes in the changes and variations in the human skeleton for the purpose of legal inquiry.

17 Human Remains 17

18 Human Remains 18 Forensic Anthropology, continued A forensic anthropologist may provide basic identification information on skeletonized or badly decomposed remains. From a whole bone or part of a bone, the scientist may be able to determine: An age range Sex Race Approximate height Cause of death, disease, or anomaly

19 Human Remains 19 Osteology Osteology is the study of bones. There are 206 bones in an adult human. Function of bones: Provide structure and rigidity Provide structure and rigidity Protect soft tissue and organs Protect soft tissue and organs Serve as an attachment for muscles Serve as an attachment for muscles Produce blood cells Produce blood cells Serve as a storage area for minerals Serve as a storage area for minerals Can detoxify the body by removing heavy metals and Can detoxify the body by removing heavy metals and other foreign elements from the blood

20 Human Remains 20 Estimation of Height The height of a person can be calculated by measuring the length of certain long bones, including the femur, tibia, humerus, and radius. Below are the equations used to determine average measurements for both male and female. (All measurements are in centimeters.) Male Height, H H = femur  2.23 + 69.08 H = tibia  2.39 + 81.68 H = humerus  2.97 + 73.57 H = radius  3.65 + 80.40 Female Height, H H = femur  2.21 + 61.41 H = tibia  2.53 + 72.57 H = humerus  3.14 + 64.97 H = radius  3.87 + 73.50

21 Human Remains 21 Age Determination Most accurate estimations are made from: Teeth Teeth Epiphyses or growth plates Epiphyses or growth plates Pubic symphysis Pubic symphysis Cranial sutures: The three major cranial sutures appear as Cranial sutures: The three major cranial sutures appear as distinct lines in youth and gradually close from the inside out. Investigators always use an age range because of the variation in people and how they age. The investigator does not want to eliminate any possibilities for identification.

22 Human Remains 22 Age By Teeth

23 Human Remains 23 Cranial sutures

24 Human Remains 24 Age Determination Using Cranial Sutures Sagittal suture completely closed Male—26 or older Female—29 or older Sagittal suture completely open Male—less than 32 Female—less than 35 Complete closure of all three major sutures Male—over 35 Female—over 50 Sagittal suture LambodialCoronal

25 Human Remains 25 Age Determination Using Basilar Suture Basilar suture Technically known as the synchondrosis spheno- occipitalis, closes in females as young as 14 and in males as young as 16. If the suture is open, the individual is generally considered to be 18 or younger.

26 Human Remains 26 Age Determination In long bones, the diaphysis, or shaft, makes up most of the bone’s length. The epiphyses are found at the ends of the bones; their function is to allow for growth. The epiphyses are good places to look for changes in estimating age. Though all people are different and grow at different rates, there are similarities that allow for generalizations in estimating age.

27 Human Remains 27 Definitions Stage 1: no epiphysis (the growth plate has not formed yet) Stage 2: non-union; the epiphysis and bone are separate Stage 3: partial union; the epiphysis is attached, but a line is visible Stage 4: complete union; the epiphysis is attached and a line is not visible

28 Human Remains 28 The Medial Clavicle in Stages 1–4

29 Human Remains 29 Age Determination Using Epiphysis Stage of Union of Medial Clavicle MaleFemale Non-union without separate epiphysis 21 or younger 20 or younger Non-union with separate epiphysis 16–2117–20 Partial union 17–3017–33 Complete union 21 or older 20 or older

30 Human Remains 30 Gender Differences in Bones Determination of sex is crucial to the analysis of unidentified human remains. The pelvis offers the most definitive traits. Comparison of three characteristics of the os pubis gives the information used to identify sex. Male PelvisFemale Pelvis

31 Human Remains 31 Gender Identification A. The female (top) has a wider pubic body than the male (bottom). B. The female has a wider subpubic concavity or subpubic angle.

32 Human Remains 32 Gender Identification, continued C. Most females have a ventral arc present.

33 Human Remains 33 Male Female Subpubic Angle 18 Human Remains

34 34 Determine which are male and which are female.

35 Human Remains 35 Gender Differences The rib cage and shoulders of males are generally wider and larger than those of females. In addition, about one person in 20 has an extra rib. This is more common in males than in females.

36 Human Remains 36 Skull Gender Differences

37 Human Remains 37 Gender Differences, continued In males, the index finger is sometimes shorter than the third finger. In females, the index finger is sometimes longer than the third finger. This is not often used as an indicator of gender, as there are many exceptions. Is this a male or female hand according to the above rule?

38 Human Remains 38 Race Race is difficult to determine from most skeletal remains, especially since pure races are becoming uncommon. An experienced forensic anthropologist can generally place skulls into one of three groups: Caucasoid—European, Middle Eastern, and Indian descent Caucasoid—European, Middle Eastern, and Indian descent Negroid—African, Aborigine, and Melanesian descent Negroid—African, Aborigine, and Melanesian descent Mongoloid—Asian, Native American, and Polynesian descent Mongoloid—Asian, Native American, and Polynesian descent

39 Human Remains 39 Race Characteristics Caucasoids—have a long, narrow nasal aperture, a triangular palate, oval orbits, narrow zygomatic arches, and narrow mandibles. Negroids—have a wide nasal aperture, a rectangular palate, square orbits, and more pronounced zygomatic arches. The long bones are longer, and have less curvature and greater density. Mongoloids—have a more rounded nasal aperture, a parabolic palate, rounded orbits, wide zygomatic arches, and more pointed mandibles.

40 Human Remains 40 What differences do you notice among these three skulls? Can you determine race?

41 Human Remains 41 Facial Restoration After determining the sex, age, and race of an individual, facial features can be built upon a skull to assist in identification. Erasers are used to make tissue depths at various points on the skull. Clay is used to build around these markers, and facial features are molded.

42 Human Remains 42 The Body Farm The Body Farm is the nickname of a two-and-a-half-acre research facility in Tennessee developed in 1980 by Bill Bass where bodies are placed in various conditions and allowed to decompose. Its main purpose is to observe and understand the processes and timetable of postmortem decay. Over the years it has helped to improve the ability to determine “time since death” in murder cases. Hic locus est ubi mortui viveuntes docent. “ This is the place where the dead teach the living.”

43 Human Remains 43 Anthropologist at Work This anthropologist is hard at work dusting away material from these embedded bones. Picture taken at Chicago’s Museum of Natural History

44 Human Remains 44 More Applications Forensic experts may be called upon to give information on the life and death of humans and animals in unique circumstances, including: Mass murder (Oklahoma bombing, plane crashes, World Trade Center) Earlier man (mummies, Iceman, Lindow Man) Historical significance (Holocaust, uncertain death of famous people) Prehistoric animals (dinosaurs)

45 Human Remains 45 Animal Facial Restoration Determining what T. Rex looked like using the bone formation. From this: To this:

46 Forensic Pathology Death Detectives

47 Kendall/Hunt Publishing Company47 Forensic Pathologist Forensic Pathologist - investigates sudden, unnatural, unexplained, or violent deaths. They usually perform autopsies to determine cause of death 4 yr. Degree + Med School + Residency + Medical Pathology Training (2 years) Work in hospitals or as medical examiner

48 Kendall/Hunt Publishing Company48 Pathologist Conclusions Five Conclusions drawn for investigation: –Natural –Homicide –Suicide –Accident –Undetermined

49 Kendall/Hunt Publishing Company49 Forensic Pathologist Way time of death are determined: –Algor Mortis - loss of body heat –Livor Mortis - 0-12 hours, settling of blood –Rigor Mortis - 24-36 hours, muscles relax and become rigid –Potassium levels on ocular fluid

50 Kendall/Hunt Publishing Company50 Livor Mortis – Lividity

51 Kendall/Hunt Publishing Company51 Rigor Mortis

52 Kendall/Hunt Publishing Company52 Pathologist v Coroner Coroner is elected official – no requirements exist, most funeral people –Historically they solved crimes –Power to call grand jury –Being eliminated in other states –Georgia still has position, county decision Fulton does not have a coroner –Mostly shuffles paperwork, defers to medical examiner’s office

53 Kendall/Hunt Publishing Company53 When notice to coroner/medical examiners office is required Death is: –Violent –Suicide –Sudden w/ apparent good health –Unattended by physician –Suspicious, especially under 16 yoa –Under 7 yoa unless expected –Execution –Inmate of state facility

54 Kendall/Hunt Publishing Company54 When notice to coroner/medical examiners office is required Once notified they decide if further investigation is needed Autopsy a possibility –Required in under 7 yoa

55 Kendall/Hunt Publishing Company55 Autopsies Means - “see for yourself” Purpose is to learn the truth about the person's health during life, and how the person really died 2 types: medical & forensic "Hic locus est ubi mors gaudet succurrere vitae“ "This is the place where death rejoices to teach those who live”

56 Kendall/Hunt Publishing Company56 Autopsies Religious Issues: –Orthodox Jews: usually require Rabbi present, very resistant to autopsies –Muslims: also resistant –State has power to ignore religious concerns

57 Kendall/Hunt Publishing Company57 Autopsies: Method examine the outside of the body body is opened using a Y-shaped incision from shoulders to mid-chest and down to the pubic region top of the skull is removed, and the brain is very carefully cut free breastbone and attached rib cartilages are removed chest organs, including the heart and lungs, are inspected

58 Kendall/Hunt Publishing Company58 Autopsies: Method take blood from the heart to check for bacteria blood, urine, bile, or even the fluid of the eye used for chemical study and to look for medicine, street drugs, alcohols, and/or poisons After any organ is removed, the pathologist will save a section in preservative solution

59 Kendall/Hunt Publishing Company59 Autopsies: Method Organs are all weighed Heart is removed Neck organs, large airways, and lungs are removed in one piece Liver is removed and sliced Digestive tract removed then renal/sex organs removed Any suspect organ is inspected closely

60 Kendall/Hunt Publishing Company60 Autopsies: Method Organs returned to cavity or cremated Body sewn up, baseball stitch Head more carefully sewn Body washed and forwarded as requested by family

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