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

Forensic Entomology

TaxonomyClassification of Things in an Orderly Way

We are interested in the phylum, Arthropoda; class, Insecta; order:

Diptera (flies) Coleoptera (beetles)

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.

The Process of DeathAlgor Mortis: Body cooling rate Hours since death = 98.4°F – internal body temperature 1.5Livor 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 bodyTemperature of body Stiffness of bodyStiffness of body Time since deathTime since death

WarmWarm Not stiffNot stiff Not dead more than 3 hoursNot dead more than 3 hours

WarmWarm StiffStiff Dead between 3 and 8 hoursDead between 3 and 8 hours

ColdCold StiffStiff Dead between 8 and 36 hoursDead between 8 and 36 hours

ColdCold Not stiffNot stiff Dead for more than 36 hoursDead for more than 36 hours

The Process of Death, continued

StageStage DescriptionDescription

Initial or fresh decay (autolysis)Initial or fresh decay (autolysis)The cadaver appears fresh externally but is The cadaver appears fresh externally but is decomposing internally due to the activities of decomposing internally due to the activities of bacteria present before death (0–4 days).bacteria present before death (0–4 days).

Putrefaction or bloatingPutrefaction or bloatingThe cadaver is swollen by gas produced internally, The cadaver is swollen by gas produced internally, accompanied by the odor of decaying flesh (4–10 accompanied by the odor of decaying flesh (4–10 days).days).

Black putrefactionBlack putrefaction

Flesh of creamy consistency, with exposed body Flesh of creamy consistency, with exposed body parts black. Body collapses as gases escape. parts black. Body collapses as gases escape. Fluids drain from body. Odor of decay very strong Fluids drain from body. Odor of decay very strong (10–20 days).(10–20 days).

Butyric fermentationButyric fermentationCadaver drying out. Some flesh remains Cadaver drying out. Some flesh remains at first; cheesy odor from butyric acid at first; cheesy odor from butyric acid (20–50 days).(20–50 days).

Dry decay (diagenesis)Dry decay (diagenesis) Cadaver almost dry; slow rate of decay. May Cadaver almost dry; slow rate of decay. May mummify (50–365 days).mummify (50–365 days).

Life Cycle of InsectsMetamorphosis

egg

larva (maggot)

pupa

winged adult

The life cycle of Musca domestica

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

Insects of DeathDiptera

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.

Insects of Death, continued

ColeopteraIn 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.

Variables Affecting Metamorphosis

TemperatureThe higher the temperature (within limits), the faster the growth.

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

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

Collection of Evidence

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Human Remains

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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.

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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

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Osteology

Osteology is the study of bones.Osteology is the study of bones.

There are 206 bones in an adult human.There are 206 bones in an adult human.

Function of bones:Function of bones:• Provide structure and rigidity Provide structure and rigidity • Protect soft tissue and organsProtect soft tissue and organs• Serve as an attachment for musclesServe as an attachment for muscles• Produce blood cellsProduce blood cells• Serve as a storage area for mineralsServe 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 bloodother foreign elements from the blood

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Estimation of Height

The height of a person can be calculated by measuring the length The height of a person can be calculated by measuring the length of certain long bones, including the femur, tibia, humerus, and of certain long bones, including the femur, tibia, humerus, and radius. Below are the equations used to determine average radius. Below are the equations used to determine average measurements for both male and female. (All measurements measurements for both male and female. (All measurements are in centimeters.)are in centimeters.)

Male Height, H

H = femur 2.23 + 69.08H = tibia 2.39 + 81.68H = humerus 2.97 + 73.57H = radius 3.65 + 80.40

Female Height, H

H = femur 2.21 + 61.41H = tibia 2.53 + 72.57H = humerus 3.14 + 64.97H = radius 3.87 + 73.50

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Age Determination

Most accurate estimations are made from:Most accurate estimations are made from:

• TeethTeeth

• Epiphyses or growth platesEpiphyses or growth plates

• Pubic symphysisPubic 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 distinct lines in youth and gradually close from the inside out.inside out.

Investigators Investigators alwaysalways use an use an age rangeage range because of the variation in because of the variation in people and how they age. The investigator does not want to people and how they age. The investigator does not want to eliminate any possibilities for identification. eliminate any possibilities for identification.

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Age By Teeth

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Cranial sutures

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Age Determination Using Cranial SuturesSagittal suture completely closedSagittal suture completely closed

MaleMale——26 or older26 or olderFemaleFemale——29 or older29 or older

Sagittal suture completely openSagittal suture completely openMaleMale——less than 32less than 32FemaleFemale——less than 35less than 35

Complete closure of all three Complete closure of all three major suturesmajor suturesMaleMale——over 35over 35FemaleFemale——over 50 over 50

Sagittal suture

Lambodial Coronal

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Age Determination Using Basilar Suture

Basilar sutureBasilar suture

Technically known as the Technically known as the synchondrosis spheno-synchondrosis spheno-occipitalis, closes in females occipitalis, closes in females as young as 14 and in males as young as 14 and in males as young as 16. If the suture is as young as 16. If the suture is open, the individual is open, the individual is generally considered to be 18 generally considered to be 18 or younger.or younger.

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Age Determination

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

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Definitions

Stage 1: no epiphysis (the growth plate has not formed yet)Stage 1: no epiphysis (the growth plate has not formed yet)

Stage 2: non-union; the epiphysis and bone are separateStage 2: non-union; the epiphysis and bone are separate

Stage 3: partial union; the epiphysis is attached, but a line is Stage 3: partial union; the epiphysis is attached, but a line is visiblevisible

Stage 4: complete union; the epiphysis is attached and a line is Stage 4: complete union; the epiphysis is attached and a line is notnot visible visible

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The Medial Clavicle in Stages 1–4

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Age Determination Using Epiphysis

Stage of UnionStage of Unionof Medial Clavicleof Medial Clavicle MaleMale FemaleFemale

Non-union without Non-union without separate epiphysisseparate epiphysis

21 or younger21 or younger 20 or younger20 or younger

Non-union with separate Non-union with separate epiphysisepiphysis

16–2116–21 17–2017–20

Partial unionPartial union 17–3017–30 17–3317–33

Complete unionComplete union 21 or older21 or older 20 or older20 or older

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Gender Differences in Bones

Determination of sex is crucial to the analysis of unidentified Determination of sex is crucial to the analysis of unidentified human remains. The pelvis offers the most definitive traits. human remains. The pelvis offers the most definitive traits. Comparison of three characteristics of the os pubis gives the Comparison of three characteristics of the os pubis gives the information used to identify sex.information used to identify sex.

Male Pelvis Female Pelvis

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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.

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Gender Identification, continuedC. Most females have a ventral arc present.

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Male Female

Subpubic Angle18

Human Remains

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Determine which are male and which are female.

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Gender Differences

The rib cage and shoulders of The rib cage and shoulders of males are generally males are generally widerwider and and largerlarger than those of females. In than those of females. In addition, about one person in addition, about one person in 20 has an extra rib. This is 20 has an extra rib. This is more common in males than in more common in males than in females.females.

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Skull Gender Differences

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Gender Differences, continuedIn males, the index finger is sometimes shorter than the In males, the index finger is sometimes shorter than the

third finger. In females, the index finger is sometimes third finger. In females, the index finger is sometimes longer than the third finger. This is not often used as an longer than the third finger. This is not often used as an indicator of gender, as there are many exceptions.indicator of gender, as there are many exceptions.

Is this a male or female hand according to the above rule?

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Race

Race is difficult to determine from most skeletal remains, especially Race is difficult to determine from most skeletal remains, especially since pure races are becoming uncommon. An experienced since pure races are becoming uncommon. An experienced forensic anthropologist can generally place skulls into one of three forensic anthropologist can generally place skulls into one of three groups:groups:

• CaucasoidCaucasoid——European, Middle Eastern, and Indian descentEuropean, Middle Eastern, and Indian descent

• NegroidNegroid——African, Aborigine, and Melanesian descent African, Aborigine, and Melanesian descent

• MongoloidMongoloid——Asian, Native American, and Polynesian descentAsian, Native American, and Polynesian descent

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Race Characteristics

CaucasoidsCaucasoids——have a long, narrow nasal aperture, a triangular have a long, narrow nasal aperture, a triangular palate, oval orbits, narrow zygomatic arches, and narrow palate, oval orbits, narrow zygomatic arches, and narrow mandibles.mandibles.

NegroidsNegroids——have a wide nasal aperture, a rectangular palate, have a wide nasal aperture, a rectangular palate, square orbits, and more pronounced zygomatic arches. The square orbits, and more pronounced zygomatic arches. The long bones are longer, and have less curvature and greater long bones are longer, and have less curvature and greater density.density.

MongoloidsMongoloids——have a more rounded nasal aperture, a have a more rounded nasal aperture, a parabolic palate, rounded orbits, wide zygomatic arches, parabolic palate, rounded orbits, wide zygomatic arches, and more pointed mandibles.and more pointed mandibles.

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

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Facial Restoration

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

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The Body Farm

The Body Farm is the nickname of a two-and-a-half-acre research facility in 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 Tennessee developed in 1980 by Bill Bass where bodies are placed in various conditions and allowed to decompose. Its main purpose is to various conditions and allowed to decompose. Its main purpose is to observe and understand the processes and timetable of postmortem observe and understand the processes and timetable of postmortem decay. Over the years it has helped to improve the ability to determine decay. Over the years it has helped to improve the ability to determine “time since death” in murder cases.“time since death” in murder cases.

Hic locus est ubi mortui viveuntes docent. Hic locus est ubi mortui viveuntes docent.

“ “ This is the place where the dead teach the living.”This is the place where the dead teach the living.”

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Anthropologist at WorkThis anthropologist ishard at work dustingaway material from these embedded bones.

Picture taken at Chicago’s Museum of Natural History

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More ApplicationsForensic experts may be called uponto give information on the life and deathof humans and animals in uniquecircumstances, 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)

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Animal Facial Restoration

Determining what T. Rex looked like using the bone formation.

From this: To this:

Forensic Pathology

Death Detectives

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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


Pathologist Conclusions

Five Conclusions drawn for investigation:– Natural

– Homicide

– Suicide

– Accident

– Undetermined


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


Livor Mortis – Lividity


Rigor Mortis


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


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


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


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”


Autopsies Religious Issues:

– Orthodox Jews: usually require Rabbi present, very resistant to autopsies

– Muslims: also resistant– State has power to ignore religious

concerns


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


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


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


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

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

Documents

human remains slide

blood slide

time of death slide

anomaly slide

insects of death diptera

decomposing body

human remains focus

body collapses