Forensic Science laboratory

INTRODUCTION
Forensic science laboratory is indispensible, one of the three fundamental pillars of criminal
judicial system and connecting link between the police and judiciary

FSL is a multidisciplinary institution in which through modern and up to date sophisticated

instrumentation and verified scientific methodology, the physical exhibits pertaining to
crime are scientifically analyzed.

Examination report of forensic science lab is established as strong evidence in establishing

the involvement of accused under IEA and Crpc 293, which is given by the director, Deputy
director or Assistant director of the concerned division.

History
 The first state forensic science laboratory in India was established in the year 1952 at
Calcutta on July1st
 It became fully operational in the year 1953
 It started functioning under the guidance of Dr. NK Sen as Director

Organisation
FSL should provide 3 major categories of service-clinical, pathological and laboratory.

 Clinical services – they include examination of victims of assaults, sexual

crime, drunkenness etc
 Pathology services – they include chemical analysis, toxicology, serology,
biology, photograph, fingerprints,ballistcs etc.

Museum – every laboratory should establish a museum containing fingerprints bullets and
catridgecases, tyre thread patterns, animal hair,soil, typewritten specimens,inks,ropes and
etc.

FORENSIC LAB CATEGORIES:

1 Central FSLs

2 State FSLs

3 Mini and local FSLs (CSFL,SFSL,RFSL,MFSL)

There are seven central forensic laboratories in India, at Hyderabad, Kolkata, Chandigarh,
New Delhi, Guwahati, Bhopal and Pune.
CSFL Hyderabad is a centre of excellence in chemical science.

CFSL Chandigarh in physical sciences.

CFSL New Delhi comes under the CBI, Delhi,whereas other laboratories are under the
control of directorate of forensic sciences services CDF SS of the ministry of home affairs.

STAFF:
 Director, medical or scientific.
 Clinical services, physical and obstetritician
 Pathology services, pathologist
 Laboratory micro analyst- Biologist, physicist, serologist, micro analyst
 Others-Librarian,liason officer
FUNCTION
 To examine ,compare and evaluate physical evidence so as to link a suspect to the
victim or the scene of a crime
 Protection of the innocent

 Training of the police investigations as to what constitutes physical evidence, how it

is to be found ,collected, preserved and delivered to the laboratory

ROLE OF FSL
 It helps in administration of justice system and provides knowledge and facilities to
various training programmes to people involved with justice delivery.
 It provides the scientific aid in criminal aid in criminal justice system
 It guides, regulates and controls the working of forensic science laboratories.
 Provides financial and technical help to State Forensic lab(SFSLs)
 Promotes research and development in forensic field. To access and review the
current procedure and practices in the labs

DIVISIONS
1.Physical division-Physical evidences collected from scenes of crime are tested in this
section.

2. Documents division- Handwritting,typewriting and examination of alleged forged

documents, currencies are undertaken in this section.

3. Chemical and toxicology division- It undertakes chemical analysis of viscera and body
fluids or other exhibit for detection of various poisons or drugs.

4. Biology divisions – Identification of different body fluids as their nature .

Example: Examination of hair of different organs is done in this section.

5.Serology- This section undertakes blood group and serological tests for different
suspicious stains, body fluids and blood.
6. Many of the evidences detected from different exhibits or materials require to be
photographed.

7. Ballistics and explosive divisions- All about firearms, missiles, gunpowder’s and other
explosives materials are examined.

8. Molecular biology division- With the use of DNA test in forensic investigation, many FSL
have started this new unit.

9. Fingerprint division- Development and study of latent and chance finger prints are the job
of this unit.

10. Polygraph division- In many countries, service of polygraph or lie detector is

incorporated in FSL.

LOCARDS EXCHANGE PRINCIPLE

 When any 2 objects come into contact, there is always a transfer of materials from
object on the other.
 It is actual evidence, and its presence is absolute proof of the crime
 Traces from the scenes may be carried away on the person or tools of the criminal.
Example: Fingerprints, footprint, fibers from clothes, blood stains , seminal stains

PHYSICAL EVIDENCES
 It is useful as it helps to decide whether a crime is committed or not
 Physical evidences cannot be wrong but eyewitness may be wrong
 The evidences which are usually handled by FSL such as weapons,firearms,bullets.
EXAMPLES:

1. In case of poisoning or food poisoning

o Chemical analysis of viscera /body fluids to know the nature of
persons.
o Chemical analysis of food/clothes if it is corroborative evidence.
2. In assault and murder
o Examination of weapons /objects.
o Blood grouping from blood stains on victim’s hair, in victim’s hand, saliva
on cigarette butts.
3. Forgery
Examination of documents, paper inks, pencil and typewriter alteration /
obliteration under UV rays .
4. Burglary
Examination of paint,algae,vegetable matter, glass fragments on his tools,
clothes /body
5. In hanging/strangulation
Matching of ligatures
6. In drowning
Detection of diatoms in body tissues and water
7. In sexual offences

Examination of vaginal fluid, blood/seminal stains to check whether crime is

committed or not. Examination of hair , epithelium.

ANALYTICAL TECHNIQUES

1. Chromatography
o It is laboratory technique for separating compounds within a mixture.
o There are 2 phases of chromatography.
o The compounds in this mixture separate due to travelling at different
velocities in mobile fluid.
o There are different chromatographic techniques.
 Columns chromatography
o It is a preparative technique used to purify compounds depending on their
polarity
o This process may directly help to detect the tested materials or help to collect
the material in the pure form after evaporation of the solvent from the level
of the columns which has absorbed the material
  Thin layer chromatography and paper chromatography or Planar
chromatography
o This technique can be used to identify substances such as ink on banknotes
or forgeries, dyes and different drugs.
o Thin layer chromatography is most commonly used technique for this
purpose .
o This technique is advantageous due to their quick and inexpensive nature.
 High performance liquid chromatography9HPLC)

It is used mainly for analyzing the contents of explosives different substances

that are used in them have different retention time due to their differing
chemical and physical properties.

 Gas chromatography
o It is widely employed technique, also known as gas-liquid
chromatography.
o It is used as screening to determine if a deceased person has ingested
drugs or alcohol prior to death.

2. Electrophoresis
 o It is a technique in which the migration and separation of charged
particles (ions) under the influence of an electric field.
o Electrophoresis can be used to analyze proteins, including those
found in human blood, electrically charged protein components move
in phase plate and at end is treated with coloring agents.

3. Spectroscopy

o There are a lot of spectroscopy, methods which are based on various

effects of retractions between radiation and matter among which
vibrational spectroscopy observe special attention.
o These methods are widely used for gathering structural information
systemic investigation such as this helps in identification of various
forms of Hb.
4. Spectrophotometer
 o These are used to measure the concentration of known substances in
a solution.
o It works by taking a sample and measuring the intensity of a light
when a beam passes through it.

5. Neutron Activation Analysis

It is useful to detect trace elements in hair, gun powder deposited around a

firearm wound, primer containing the hand of the user of a gun etc.

6. Microscopes

o This helps in identification of minute trace elements present on the

surface of a matter.
 o There are different types of microscopes such as stereoscopic,
comparative, fluorescent, polo rising and electron microscope.
o Microscope can be utilized for detection of extensive range of trace
elements available in dress and other articles of the accused or victim.

7. Polygraph/lie detector

 It is the process which is used in medical practices for comprehensive study of

functioning of different body systems with particular reference to circulation.
 The basis of its application is the fact that with mental excitation or stimulation
there is alteration of these body functions due to autonomic /sympathetic
excitation.
 Polygraph process uses and records:
I. Bp
II. Pulse
III. Heart rate
IV. Respiratory rate
V. Psycho galvanic reflex

 Such phenomenon reflects emotional reaction which is used in detecting

deception . It is popularly known as lie detector . The tracing made is called as
PolyGram.
 Procedure
I. Consent of persons is taken prior to procedure and the process is
explained to person.
II. The person has to answer questions in YES or NO as answer.
 III. Usually not more than 10 questions are asked to a person in a given
time
Irrelevant question- Having no relation with incident
Relevant questions-Having relation with incident
Control question
 Among all responses , responses to change in respiration and galvanic skin
reaction are assumed to be more reliable.
8. Narcoanalysis

 Also known as “Truth serum drugs”

 This is based on the principle , that at a appoint very close to unconsciousness ,
the subject will be mentally incapable of resistance to questioning and
incapable of inventing the falsehoods that he has used to conceal the guilt.
 It involves administration of light anesthetic agents/drugs intravenously.
 Drugs used are –Thiopentane Sodium
Scopolamine hydrovromic
Benzodiazepines
 Large number of false negatives are common.

9. Brain fingerprinting
 It is developed by Dr. Lawrance A .Farwel of USA
Brain fingerprinting determines specific information i.e, present in the brain of criminal
regarding criminal act.
The suspected person is questioned about the crime and also shown the visuals of the
crime scene on computer screen. Apart from his verbal replies another computer
keeps track of the neuro impulses.
Intensity of brain waves shoots up when a suspect is the perpetrator of the crime.
It is more accurate than polygraphic test.