Narco Test

Table of Contents

What is Narco Test

Narco Test involves intravenous administration of a drug (such as sodium pentothal, scopolamine and sodium amytal) into an individual. The drug is also known as ‘truth serum’.
Working: During the narco test, the person’s inhibitions are lowered by interfering with their nervous system at the molecular level, through usage of drugs.
- This allows them to speak without inhibition. During this stage, the person is more likely to divulge information, which would usually not be revealed in the conscious state.
Need for Narco Test: The test is carried out after other evidences do not provide a clear picture of the case or the investigators believe that accused is hiding facts.
Guidelines: The Narco test is carried out under the guidance and supervision of a psychologist, an investigating officer, or a forensic expert.

Sodium pentothal or sodium thiopental is a fast-acting, short duration anaesthetic.
It is used in larger doses to sedate patients during surgery. It belongs to the barbiturate class of drugs that act on the central nervous system as depressants.

Before the injection of drug, the subject has to undergo a general medical examination to check their condition.
The dosage of drug depends on the subject’s age, sex and other possible medical conditions they may have.
Subject is nearly sedated by this drug and is allowed reach a semi-conscious state where they can answer specific questions.
The person concerned is interrogated by the investigators in the presence of doctors. The revelations made during this stage are video recorded.
The report provided by the expert is used in the process of collecting evidence. The procedure takes place in a government hospital, after a court order permitting the same.
Accuracy of Narco Test:
- The accuracy of narco tests is not 100 per cent. Many subjects have made false statements in their drugged state.
- This method has been deemed as unscientific method of investigation.

In Selvi & Ors vs State of Karnataka & Anr (2010), the Supreme Court has ruled that narco analysis, brain mapping and polygraph tests cannot be conducted on any person without his or her consent.
Those who volunteer for the procedure must have access to a lawyer, and have the physical, emotional, and legal implications of the test explained to them by police and the lawyer.
Statements made by the subject during narco analysis test are not admissible in the court, except under certain circumstances.
However, any information or material subsequently discovered with the help of statement made during such test can be admitted as evidence.
Significance of narco test:
- Scientific techniques such as narco test would reduce ‘third degree’ methods currently used by investigators to obtain information from accused.

The Supreme Court had allowed narco test in the 2002 Godhra riots case. It was also used on Abdul Karim Telgi, in the Telgi stamp paper scam.
The accused in the 2007 Hyderabad twin blasts case were also put under a narco test.

Polygraph Test:

A polygraph test is based on the belief that physiological responses that are triggered when an individual is lying are different from what they would be otherwise.
The process does not involve injecting drugs into the body; instead instruments like cardio-cuffs or sensitive electrodes are attached to the suspect.
Variables such as blood pressure, respiration, pulse rate, change in sweat gland activity, blood flow, etc., are measured as questions are put to them.
A numerical value is assigned to each response to conclude whether the person is telling the truth, is deceiving, or is uncertain.

Brain Mapping:

Brain mapping test determines if a person is friendly with given knowledge by measuring brain activity in response to selected stimuli.
Sensors are attached to the scalp of the accused and he/she is shown words, images or videos that stimulate brain activity.
If the individual has knowledge about the particular information, a particular wave is generated in brain, which is captured by the sensors. This helps investigators find out if the accused is lying or not.

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