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CHAPTER 2: IDENTIFICATION

Comprehensive WBUHS Exam-Oriented Answers

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Q1. Define Personal Identification and Discuss Its Medico-legal Importance

Definition

Medico-legal Importance (enumerate all in exams):

1. Criminal cases - To identify accused persons, victims, or eyewitnesses
2. Civil cases - For claims of insurance, inheritance, disputed marriage, adoption
3. Mass disasters - Railway accidents, air crashes, floods, earthquakes - to identify multiple decomposed/mutilated bodies
4. Disputed identity - Cases of personation, mistaken identity
5. Unknown dead bodies - Found in rivers, roads, railways, construction sites
6. Amnesia cases - Persons suffering from loss of memory
7. Immigration issues - To verify claimed identity
8. Missing persons and kidnapping cases
9. War casualties and terrorist incidents
10. Disputed birth records - Parentage determination

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Q2. Methods of Identification - Primary and Secondary Classification

Primary (Absolute) Methods:

1. Dactylography (Fingerprinting) - Most reliable and absolute; no two persons have identical fingerprints
2. DNA profiling (DNA Fingerprinting) - Except identical twins, each person's DNA is unique
3. Dental identification (Forensic Odontology) - Teeth are extremely durable; dental records compared
4. Anthropometry (Bertillon system) - Measurement of fixed body parts (now historical)

Secondary Methods:

1. Personal identity documents - Aadhar, passport, voter ID, ration card
2. Clothing and personal belongings - Jewelry, watch, spectacles
3. Tattoo marks - Permanent unless deliberately obliterated
4. Scars, deformities, physical peculiarities
5. Hair examination - Color, texture, racial characteristics
6. Anthropological methods - Age, sex, stature, race estimation from bones
7. Superimposition technique - Skull-photograph superimposition
8. Photographs
9. Radiological comparison - Bone trabecular pattern
10. Blood group determination

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Q3. DACTYLOGRAPHY / FINGERPRINTS

Definition

Three Fundamental Principles (Galton's Laws):

1. Permanence - The ridge pattern is formed in the 3rd-4th month of fetal life and remains unchanged throughout life and after death (until putrefaction destroys skin). Even if superficial skin is destroyed, ridges regenerate exactly.
2. Individuality (Uniqueness) - No two individuals (not even identical twins) have the same fingerprint pattern on the same finger. No two fingers of the same person are identical.
3. Classifiability - Fingerprints have general ridge characteristics that allow them to be systematically classified.

History:

• Purkinje (1823) - First systematic classification of finger patterns (9 types)
• W.J. Herschel (1858) - First official use of fingerprints in India; used in Bengal to prevent fraud
• Henry Faulds (1880) - Wrote about practical use for identifying criminals
• Francis Galton (1892) - Established individuality and permanence; published "Fingerprints"
• Edward Richard Henry (IG Bengal) - Developed modern Henry-Vucetich classification system
• First Fingerprint Bureau in the world - Established in Calcutta, June 1897

Primary Patterns of Fingerprints (3 types):

Galton's Details (Minor characteristics of ridges):

1. Ridge ending / termination
2. Bifurcation / fork
3. Short independent ridge (island)
4. Enclosure (lake)
5. Spur (hook)
6. Cross bridge

Types of Fingerprint Impressions:

• Patent prints - Visible without any development (e.g., bloody fingerprints, prints in dust)
• Plastic prints - Left in soft material (wax, putty, soft soap); 3D impressions
• Latent prints - Not visible to naked eye; require development (most commonly encountered at crime scenes)

Development of Latent Fingerprints:

• Dusting - Aluminum powder (on dark surfaces), lamp black/carbon powder (on light surfaces)
• Iodine fuming - Temporary; iodine vapors condense on sweat residue
• Ninhydrin spray - Reacts with amino acids in sweat; gives purple/pink (Ruhemann's purple) color
• Silver nitrate - Reacts with NaCl in sweat; turns black in UV light

• Ninhydrin, silver nitrate

Fingerprints from Dead Bodies:

1. Fresh body - Direct inking and rolling
2. Putrefied/macerated body - Re-injection of glycerin under dermis; using de-gloved skin like a glove
3. Shriveled/wrinkled fingers - Re-hydrate with glycerin or silicone injection
4. Mummified body - Soaking in warm water or 1% NaOH solution first

Poroscopy (described by Locard):

• Ridges on fingers are studded with microscopic pores (mouths of sweat gland ducts)
• Each millimeter of ridge contains 9-18 pores
• These are permanent and vary in size, shape, position, number in each individual
• Used when only fragments of fingerprints are available

Why Dactylography is Superior to All Other Methods:

• Absolute, infallible, never changes throughout life
• Can be obtained from skeleton (fingertip bone impression sometimes retained)
• Cannot be forged (deliberate obliteration creates permanent scars, which themselves become new identification features)
• Supreme Court of India (1978) accepted fingerprint evidence on 8 matching points

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Q4. DNA PROFILING (DNA Fingerprinting)

Introduction:

• Developed by Sir Alec Jeffreys in 1984 at Leicester University, UK
• First used in a criminal case in 1987
• Principle: Except for identical twins, no two persons have the same DNA pattern
• DNA is present in every nucleated cell

Sources of DNA for Testing:

• Blood (leucocytes)
• Semen/seminal fluid
• Saliva
• Bone marrow
• Dental pulp
• Hair with root sheath cells
• Skin
• Muscle
• Brain tissue
• Dried biological stains at crime scene

Technique - Steps in DNA Profiling:

1. Extraction - DNA extracted from biological sample
2. Restriction - Cutting DNA using restriction endonuclease enzymes (molecular scissors) at specific sequences
3. Electrophoresis - DNA fragments separated by gel electrophoresis (smaller fragments travel faster)
4. Southern Blotting - Transfer of DNA fragments from gel to nylon membrane
5. Hybridization - Radioactive probes attach to specific complementary DNA sequences
6. Autoradiography - X-ray film exposed; produces characteristic banding pattern (the "DNA fingerprint")

For Degraded/Old Samples - PCR (Polymerase Chain Reaction):

• Used when DNA is limited or degraded
• Amplifies tiny amounts of DNA millions of times
• Used for: old blood stains, mummified remains, bones, teeth
• Most important technique for forensic DNA from degraded samples

Forensic Applications of DNA Profiling:

1. Criminal identification - Match suspect's DNA with crime scene biological material
2. Rape cases - Semen in vagina matched with accused's blood DNA
3. Mass disasters - Identify decomposed/mutilated bodies in accidents
4. Parentage disputes - Paternity/maternity determination (absolute identification possible, not just exclusion)
5. Linking body parts - Match different body parts from same person
6. Immigration cases - Verify family relationships
7. Missing persons
8. Baby mix-ups in hospital
9. Sex determination from foetal cells in maternal blood (Y chromosome sequences from 5th week)

Advantages over Blood Group Testing:

• Can distinguish mixed semen + vaginal fluids (blood grouping cannot)
• Gives positive identification (blood grouping gives only exclusion)
• Works on degraded samples using PCR
• Applicable to very small samples

Limitations/Legal Issues:

• Requires careful chain of evidence to prevent contamination
• Gujarat High Court (Premjibhai case 2009): "Random occurrence ratio must be provided; match alone is not conclusive proof"
• Supreme Court (Smt. Kamti Devi vs Poshi Ram 2001): "Only a genuine DNA test is scientifically accurate"
• Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad - Nodal agency in India
• No published Indian population database exists as of yet
• A DNA report without statistical probabilities is not accepted by courts as infallible evidence
• Identical twins cannot be distinguished

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Q5. DENTAL IDENTIFICATION (Forensic Odontology)

Why Teeth are Important for Identification:

• Teeth are the most durable structures in the human body - resist fire, decomposition, immersion
• Survive mass disasters (fires, explosions, aircraft accidents)
• Individual teeth characteristics (restorations, extractions, anomalies) are unique

Age Estimation from Teeth:

Below 25 years (Eruption method):

Above 25 years (Gustafson's Method - 1950):

1. Attrition (A) - Wearing down of occlusal surface
2. Periodontosis (P) - Recession of gum margin (periodontal disease)
3. Secondary dentine formation (S) - Deposition in pulp cavity
4. Cementum apposition (C) - Deposition at root apex
5. Root resorption (R) - From apex upward
6. Root translucency (T) - Transparency of root starting at apex

Dental Identification in Mass Disasters:

• Antemortem dental records compared with postmortem findings
• Unique dental restorations (fillings, crowns, bridges), missing teeth, dental anomalies
• INTERPOL uses dental comparison as one of primary identification methods

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Q6. AGE ESTIMATION FROM BONES (Skeletal Age Estimation)

From Long Bone Epiphyseal Fusion:

From the Skull (Sutural Closure - Todd & Lyon):

• 20-30 years: Endocranial sagittal suture begins closing
• 30-40 years: Coronal and lambdoid begin closing
• 40-50 years: All major sutures closed endocranially
• 50+ years: Ectocranial closure, sutures may be completely obliterated

From the Pubic Symphysis (McKern & Stewart):

Osteon Counting Method:

Biological Age vs Chronological Age:

• Biological (physiological) age = Age estimated from the state of development/degeneration of tissues
• Chronological age = Age from birth certificate
• These may differ; biological age is what forensic expert estimates
• Medico-legal importance: Criminal liability, marriage, voting, insurance, service records

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Q7. SEX DETERMINATION

From Pelvis (Most Reliable Bone):

From Skull:

From Femur (Dikshit):

• Vertical diameter of femur head >48 mm = Male; <43 mm = Female
• Maximum length >455 mm = Male

Barr Body (Chromatin Sex Determination):

• The sex chromatin or Barr body is the condensed, inactive X chromosome
• Formula: Number of Barr bodies = (Number of X chromosomes) - 1
• Normal female (46,XX): 1 Barr body
• Normal male (46,XY): 0 Barr bodies
• Klinefelter syndrome (47,XXY): 1 Barr body (as in question 11 - one Barr body = female sex chromosomally, but clinically Klinefelter male)
• Turner syndrome (45,X): 0 Barr bodies

1. Cresyl violet (most common)
2. Feulgen stain
3. Aceto-orcein
4. Haematoxylin and Eosin

Klinefelter Syndrome (47,XXY):

• Phenotype: Male
• Genotype: 47,XXY
• 1 Barr body present
• Testicular biopsy: Hyalinized (atrophic) seminiferous tubules, absent spermatogenesis, Leydig cell hyperplasia
• Features: Tall, eunuchoid, small testes, gynecomastia, infertility

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Q8. STATURE ESTIMATION

From Long Bones (Pearson's Regression Formula):

• Most accurate from femur (longest bone), then tibia, humerus, radius

• From femur: Height = 81.306 + 1.880 × femur length (cm)
• From tibia: Height = 86.465 + 2.890 × tibia length
• From humerus: Height = 97.294 + 2.894 × humerus length

Trotter and Gleser Formulae:

• More accurate; separate formulae for different racial groups
• Widely used in modern forensic anthropology

From Height of Intact Cadaver:

• Actual height measured; ~1.5% allowance for postmortem elongation (due to laxity of intervertebral discs)

From Vertebral Column:

• Sum of all vertebral body heights + allowances for discs

From Skull:

• Length of skull (basion-bregma) and width provide indirect estimate

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Q9. TATTOO MARKS

Definition:

Medico-legal Significance of Tattoo:

1. Identification - Of unknown living/dead persons; frequently helps identify bodies when all other features are obliterated
2. Provides information about:
   • Religion (e.g., "OM" in Devnagari script, cross, crescent)
   • Nationality/community
   • Personal relationships (partner's name)
   • Gang/criminal associations
   • Army/military service

Methods of Making Tattoo:

1. Pricking method - Traditional method; needle or pin dipped in ink; pricked into dermis
2. Cutting method - Skin cut, colored material rubbed in
3. Electric tattooing machine - Modern method; oscillating needle with electric motor

Pigments used:

• Black/dark blue: India ink (carbon), lamp black
• Red: Cinnabar (mercuric sulphide)
• Green: Chrome oxide
• Yellow: Cadmium sulfide
• White: Lead oxide (titanium dioxide)

Methods of Removal of Tattoo:

1. Surgical excision - Complete; scar remains - most definitive method
2. Dermabrasion - Mechanical abrasion of skin layers
3. Salabrasion - Rubbing with moist gauze saturated in salt
4. Laser treatment - Q-switched Nd:YAG laser; photoacoustic disruption of pigment particles; most advanced
5. Chemical methods - Application of tannic acid + silver nitrate
6. Cauterization - Thermal destruction

Forensic Significance of Removal Attempts:

• Even after removal, ghost tattoo or scar remains visible to naked eye or under UV/infrared light
• Histologically, pigment granules remain in macrophages in dermis
• Under infrared light/photography - pigment becomes visible even after superficial removal
• Deliberate removal suggests criminal activity/attempt to hide identity

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Q10. HAIR EXAMINATION

Differentiation of Human vs Animal Hair (Microscopic):

Human Hair Racial Characteristics:

Structural Characteristics of Hair:

• Cuticle - Outermost layer; overlapping scales
• Cortex - Middle layer; spindle-shaped cells, pigment granules, air spaces (cortical fusi)
• Medulla - Central core; air spaces; may be continuous, interrupted, or absent

What Can Be Determined from Hair:

1. Human or animal origin
2. Race
3. Sex (limited; DNA from root sheath more reliable)
4. Age (infant hair vs adult vs senile)
5. Region of body (head, pubic, axillary, beard)
6. Forcibly removed or naturally shed (root tag presence)
7. Toxicological analysis (arsenic, drugs)
8. DNA profiling (from root sheath cells)

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Q11. LOCARD'S EXCHANGE PRINCIPLE

Principle (Edmond Locard, 1928):

1. Leaves something behind at the scene (hair, fingerprints, fibers, soil, blood)
2. Takes something away with him (fibers, hairs, soil, victim's blood)

Application in Forensic Practice:

• Collection of trace evidence at crime scene: hair, fibers, glass fragments, paint chips, soil
• Finding victim's material on suspect's clothing and vice versa
• Basis for trace evidence analysis in forensic science

Importance in Examination of Unknown Skeletal Remains (Question 3 - JMN):

1. Samples to preserve: Teeth (for DNA, age estimation), long bones (for age, sex, stature), soil around bones, any foreign material adhering to bones (trace evidence - Locard's principle)
2. Why preserved: DNA profiling, toxicology, trace evidence analysis, establish time since death by taphonomic study

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Q12. SKULL-FACE SUPERIMPOSITION

Principle:

• Photograph of known person superimposed on skull image using video/computerized technique
• If skull matches - positive opinion can be given
• If skull does not match - definitive opinion of exclusion can be given

Important Exam Point (from WBUHS colleges):

• "Definitive opinion can be given after superimposition if skull DOESN'T match" (Sanaka) - This is the CORRECT statement
• If skull matches, opinion given is "consistent with" - not absolutely definitive
• Because: One can exclude with certainty; can only suggest probability when including

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SCENARIO-BASED ANSWERS (from WBUHS Questions)

For Question 1 (Railway accident - charred body):

1. Take all secondary methods: clothing, jewelry, personal belongings
2. Dental examination - teeth survive fire; dental records comparison
3. Fingerprints - if fingers not charred, use ninhydrin/silver nitrate on fragments
4. Tattoo marks - may survive surface charring; look under dermis
5. DNA profiling from bone marrow, dental pulp (most heat-resistant), blood relatives comparison
6. Radiological comparison - bone trabecular pattern, old healed fractures
7. Anthropological examination for age, sex, stature

For Question 3 (Bundle of bones from construction site):

For Question 11 (Mutilated body - Raiganj):

• Tattoo "TRISHUL" - Permanent identification; forensic significance
• 28 teeth all permanent, spaced jaws - All permanent teeth erupted (6-year molar to 3rd molar) + spacing = above 17-18 years; no wisdom teeth erupting = may be >25 years but teeth count of 28 (no wisdom) or 32; spacing suggests older adult
• Rounded orbit, U-shaped chin, prominent frontal and parietal eminences = Female skull
• One Barr body = 2 X chromosomes = Klinefelter syndrome (47,XXY) = Genetic female karyotype / chromatin-positive male
• Combined sex determination: Skull = female morphology, but Barr body = Klinefelter; final sex = biological male (Klinefelter) with female skull features

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SHORT NOTES (5 & 4 Mark Topics from WBUHS)

Latent Fingerprint:

Dactylography is the Best Datum for Identification (Why):

1. Permanent - from 3rd month fetal life to complete putrefaction
2. Unique - no two identical (even twins differ)
3. Classifiable - Henry-Vucetich system allows systematic searching
4. Cannot be successfully obliterated (scar becomes new mark)
5. Supreme Court accepted under Section 293 CrPC
6. First fingerprint bureau in world = Calcutta, 1897

PCR / DNA Profiling from Degraded Blood:

• PCR (Polymerase Chain Reaction) is the method of choice for degraded/old DNA samples
• Amplifies minimal DNA; works on blood stains years old, old bones, charred material
• Used in India by CDFD, Hyderabad

Significance of Tattoo Mark in Forensic Medicine:

1. Permanent identification mark even after death
2. Survives moderate decomposition and injury
3. Indicates religion, nationality, gang affiliation
4. Ghost tattoo visible under infrared even after removal attempts
5. Age of tattoo can sometimes be estimated by degree of pigment fading

Sex Determination from Femur (Bankura Sammilani):

• Vertical diameter of head: >48 mm = Male; <43 mm = Female; 43-48 mm = overlapping
• Maximum length: >455 mm male, <430 mm female
• Bicondylar width, neck-shaft angle also used

Ages of 6-11 Years as Mixed Dentition:

• 6 years: First permanent molar erupts
• 7-8 years: Deciduous central incisors shed; permanent central incisors erupt
• 8-10 years: Lateral incisors transition
• 10-11 years: Canines and premolars transitioning
• 11 years: All anteriors permanent; second permanent molars start
• Up to 11 years: Both deciduous and permanent teeth coexist = mixed dentition

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EXAM TIPS (WBUHS Pattern)

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