NATURE N SCOPE OF FB, hair, skull, diatoms .etc.MANDATORY

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NATURE AND SCOPE OF FORENSIC BIOLOGY Forensic Biology is the branch of science dealing with examinations of biological materials encountered in crimes such as murder, road accidents, burglary, robbery, dacoit, sexual assault etc. The biological materials derived from human, animal and plant sources will be identified, examined and compared.


CASES UNDER FORENSIC BIOLOGY Forensic Biology deals with the following types of crime cases Murder Road accidents Sexual assault Theft Burglary Robbery Dacoit Drowning Suspicious death Cases of missing persons .


EVIDENCES UNDER FORENSIC BIOLOGY Skull and Bones Teeth Hairs Fibers Diatoms Plant material (Tobacco, Pollen grains, wood etc.,) Insects and Maggots Skull superimposition

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Forensic Anthropology Study of human skeletal remains to determine sex, age, race, and time of death in an effort to identify an individual


STUDY OF SKELETAL REMAINS a) Belongs to one or more persons b) Male / female c) Age d) Ethnic group e) Time of death f) Cause of death. g) Peculiar features ( if any) h) Teeth which are indestructible ( in fires / mass disasters ) can be used for identification



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SKULL AND TEETH GENDER DETERMINATIONS Skull Male skulls are larger than female skulls The male has a higher forehead than a female, and a more sloping frontal area. Females have sharper superior orbital borders. Males have a more pronounced brow ridge. Supra orbital ridges are extreme in males and slight in females. Square chins indicate male. Round chins indicate female.


SKULL AND TEETH GENDER DETERMINATIONS Teeth ·Males have much larger teeth. Males have a larger mandible.

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Surgeries or healed wounds aid in identification

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Determination of Sex Pelvis is the best part for sex determination females have wider sub pubic angle females have a wider sciatic notch females have a broad pelvic inlet

Age Determination Using the Skull :

Age Determination Using the Skull Bones don’t reach maturity at the same rate – possible to tell age Suture marks on skull Immature skull has fontanels Suture marks slowly disappear as bones mature Coronal – closes at age 50 Lamboidal – begins closing at 21, closed by 30 Squamosal

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AGE DETERMINATIONS Skull The cranium of a baby is not solid, but divided into four pieces. Studying the calvarium, which is much larger in relation to the face between ages 0-5 , can determine age. The brain sutures are very far apart.


AGE DETERMINATIONS Studying a skull that is 18-23 years of age demonstrates: -A relatively larger skull size. -Closer (almost meeting) brain sutures.

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Determination of Sex Other bones are not usually as good an indicator regarding sex


FORENSIC ODONTOLOGY Odontologists or dentists use tooth as a tool in the identification of degraded remains. Remains that have been buried for a long period or which have undergone fire damage often contain few clues to the identity of the individual. Tooth enamel as the hardest substance in the human body often endures and as such odontologists can in some circumstances compare recovered remains to dental records.

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TEETH The study of teeth, their development, structure, function is called Odontology. There are 2 sets of teeth called temporary & permanent teeth. Temporary teeth are also called deciduous teeth or milk teeth, are 20 in number, include 4 incisors, 2 canines & 4 molars in each jaw. They appear during infancy are shed in the course of few years & are replaced by the permanent teeth which are 32 in number, consisting of 4 incisors, 2 canines, 4 premolars & 6 molars in each jaw.


FORENSIC IMPORTANCE OF TEETH Teeth are practically indestructible, therefore in cases of fire, mass disasters etc., Examination of the victims` teeth for its arrangement and position in the jaws, dental fillings etc., with ante mortem dental records could be useful in the identification of an individual

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FORENSIC IMPORTANCE OF TEETH By noting the number & position of teeth erupted & with x-ray examination with some amount of certainty it is possible to estimate the age of an individual up to 17-20 years of age. Beyond that age it would be rather rough approximation.

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BITE MARKS identification of bite marks on victims comparison of bite marks with teeth of a suspect identification of unknown bodies through dental records age estimations of skeletal remains victim identification through DNA analysis

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Examination of bite marks with the teeth of the suspect is helpful in identifying the criminal. Bite mark appears as a circular or oval patterned injury measuring 3-5 cm in diameter in arches facing each other. The best way to preserve the bite marks is – photographs.

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Forensic Odontology – Bite Marks Physical Characteristics distance from cuspid to cuspid tooth alignment teeth width, thickness, spacing missing teeth wear patterns including chips and grinding dental history including fillings, crowns, etc.


DIATOMS Diatoms are microscopic unicellular or colonial algae. They usually have strong cell wall impregnated with silica These can resist acid action and heat


IMPORTANCE OF DIATOMS The nature of diatoms found in the autopsied body indicates the site of occurrence of death. Diatom test is positive if a person alive is thrown into the water Diatom test is negative if dead bodies are thrown into the water bodies.


DIATOMS Sample from site of drowning Compare with diatoms isolated from long bones and sternum of the dead body. If matched Proves ante mortem drowning in that site .


WHAT IS FORENSIC ENTOMOLOGY Forensic entomology is the application and study of Insects and other arthropod biology to criminal matters. Forensic entomology is primarily associated with death investigations , however, it may also be used to detect drugs and poisons, determine the location of an incident .


ENTOMOLOGY the study of insects Entomology :- - recognition of insects. - time of death basing on development of insects & their off springs - egg laying by the blow flies - attracts insects depending on its stage of decomposition - appearance of various kinds of insects in chronological order which is well established - fully grown larva – time 5 to 7 days

Life Cycle of a Fly:

Life Cycle of a Fly Flies lay 100-150 eggs at a time. Eggs hatch-1st instar Larva molt-2nd instar Larva molt again-3rd instar Pupa -- cocoon Adult fly

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Collection :- - collect larva in hot alcohol & sent - collect larva in wide mouth container with a small piece of flesh from dead body ( for feeding)- cover with cloth piece ( for air)


HAIR Hair is the most common physical evidence encountered in crime scenes If only a single hair is found from the place of occurrence then it may be quite sufficient to detect and prove the guilt of a person and to protect the innocent


HAIR Common physical evidence . Present in the scene, on victim, on accused, on weapon, on clothing, etc., > Accused hair in victims wrist. Road accident-victims hair on vehicle. Prove the presence of accused. Grows from the hair follicles present on skin. Hair= root + shaft. Composed of fibrils made of protein – “Keratin” which are cross linked – resulting stable structure. Central portion – medulla, middle – cortex & the outer part – cuticle.



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Cuticle:- Outermost layer of hair. Thin translucent pigment free scales laid one over the other. Scales are directed towards the tip of hair. Human – flat, sheep – saw tooth type protrusions.



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Cortex:- Consists of elongated filaments – parallel to the length of hair – are bounded together by protein – to form hard structure. Empty air spaces called cortical fusi – whose shape, size and distribution are important characteristics. Contains pigments – granules (melanin) – synthesized in the hair follicle and passed to the growing hair. Concentration of melanin that decides the color of hair. Black – more melanin, gray – no melanin. Melanin is more in head – hair. Uneven pigmentation in the auxiliary / pubic hair.

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Medulla:- Central core of hair. Cells are cylindrical – contains glycogen. In some animals it is pigmented & appears dark. Its presence and appearance are characteristic feature. May be continuous / discontinuous / fragmentary / absent. Medullary index – ratio of diameter of medulla & the diameter of hair – varies – Human 1/3 or less – narrow - Animals – medium size – in cows & horses - thick – in other animals - continuous .



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Distal tip of hair :- Examine to know whether it is Recently cut, uncut, burnt or badly damaged Uncut hair shows tapered & un -pigmented tip Scissors cut- cut end is compressed. Blade / sharp object cut- an oblique cut Heavy blunt object strike – split ends Burnt – swollen end Cut ends slowly fold over- within two weeks-forms a rounded tip.

Razor cut hair; split hair; with cut tip:

Razor cut hair; split hair; with cut tip sample is taken, min 25 full-length hairs. plucked and combed hairs, packaged separately. suspects and victims and other individuals (elimination samples).

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Examination :- - - stereomicroscope – matter adhering – may reveal the profession. - Full hair root – a pulled out hair - Dried hair root – naturally fallen - Distal tip – cut / uncut –the time & type of treatment - Cross section – by microtome & examination under magnification – nature of cortex & medulla - Metallic poisons – by NAA - Sex – hair root – nuclear sexing - ABO – hair root - DNA – hair root

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Collection :- - locate with strong light - Collect with tweezers / transparent adhesive tape & preserve in clean covers - Record from where the hair is collected - Collect hair by vigorously combing from victim & suspect - In case of clipping – it should be done close to the root .


Fibres Encountered in sexual offences , murder , house breaking , road accidents etc. Carpet fibres may be transferred to accused footwear Two types – natural and man made Natural – a) vegetable- cotton , flax , hemp, jute, sisal , coir b) animal – wool , silk, mohair , cashmere , angora c) mineral – asbestos > Man made fibers- nylon – polyester, Rayon ,Acrylic, Teflon, Polypropylene, Triacetate, etc.;

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Structure :- Tough , pliable & filament like substances Long chain like structures of several similar units The smallest visible unit – which can be spun into textiles Wool – - one kind of hair – having scales - diameter changes with type of scale structure - medulla may / may not be pronounced Cotton – - common in clothing - flattened ribbon with characteristic twists - dark central area due to air inclusions & fibrilar structure

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Mercerized cotton :- - treated with strong caustic solutions - closed internal canal - lustrous surface - used in socks, women apparel, etc, Silk:- - from silk worms - long continuous fiber - types - raw, processed and wild - raw – two fibres enclosed in sericin - surface is irregular with folds & uneven lumps - processed – sericin is removed - smooth ,translucent and structure less - wild – broad in size with more fibrils

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Rayon :- - manufactured from cellulose & its derivatives - variety of fibres with different chemical composition and appearance - types- viscose , acetate, nitro cellulose, etc. Ropes, cordages :- - from cotton , jute, sisal, hemp - Types of twist – left (s-shape) & right (z- shape) - Angle of twist - Length of ten twists

Left hand twist of the rope [s configuration]:

Left hand twist of the rope [ s configuration]

Right hand twist of the rope [ z configuration]:

Right hand twist of the rope [ z configuration]

Length of strand:

Length of strand Length of 10 strands

Angle of the strand twist:

Angle of the strand twist

Cordage: :

Cordage: Cordage in the form of fibres and strings may be encountered in homicidal or suicidal cases or for tying objects, strangulation, hanging, tying contraband or stolen property. Rope bending window bars in a burglary. Structure , size, shape, appearance with another traced to the suspect ’ s possession

Rope :

Rope is usually made of hemp , jute or coir. Twisting strands together makes it. Twisting threads makes each strand and twisting fibres makes each thread.

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Collection :- - use vacuum cleaner / clean broom - place it in a clean paper & then in a cover - clothing of accused & victim worn at the time of offence – as early as possible - pack each exhibit separately & label them


SKULL SUPERIMPOSITION Establishing the identity of a missing person with the help of the latest photograph and skull in question is done with the help of a technique called skull superimposition


SUPERIMPOSITION It can be done by two methods Photo superimposition method Video superimposition method

Superimposition of Skull:

Superimposition of Skull Forms the bony core of the head & face Person can be identified – by superimposition of negatives of skull & of life size photo of the deceased A recent photo of deceased ( front view, lateral / semi lateral view ) is required Enlargement can be done by considering a standard point (like nose ring, ear ring, necklace, design of dress, etc.,) so that the interpupillary distance corresponds to the two orbits of the skull.

Superimposition of Skull:

Superimposition of Skull While superimposing the following should be considered – eyes in orbits, point at which nasal bone joined with forehead (nasion) , point between two front incisor teeth on upper jaw (prosthion), the nasal spine & lower border of the nose - Perfect matching - if all anatomical landmarks in both the photographs superimposed- then the skull is identified with the missing person


SCOPE AND PROBATIVE VALUE In crimes such as murder, road accidents, sexual assaults etc., biological evidences are encountered as physical evidence at the scene, on the accused or on the victim. Examinations can be done to identify them and to compare these exhibits with control samples, and a linkage can be established between the crime scene, victim and the culprit.

Super imposition (lateral) :

Super imposition (lateral)

Frontal skull on photo:

Frontal skull on photo

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