What is a narco test, how does it work?

May 28, 2023

Why in News?

Protesting wrestlers at Jantar Mantar recently said they were willing to undergo a narco analysis test, provided it was monitored by the Supreme Court.
The remark was made in response to Wrestling Federation of India (WFI) president comment that he was ready to undergo the narco test on the condition that wrestlers take one too

What’s in Today’s Article?

What is a Narco Test?

In a ‘narco’ or narco analysis test, a drug called sodium pentothal is injected into the body of the accused, which transports them to a hypnotic or sedated state in which their imagination is neutralised.
- Sodium pentothal/sodium thiopental is a fast-acting, short-duration anaesthetic 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.
- Because the drug is believed to weaken the subject’s resolve to lie, it is sometimes referred to as a “truth serum”, used by intelligence operatives first during World War II.
In this hypnotic state, the accused is understood as being incapable of lying and is expected to give information that is true.

Narco Tests vs Polygraph Tests:

Polygraph tests, although having the same truth-decoding motive, work differently.
A polygraph test is carried out on the assumption that physiological responses triggered when one is lying are different from what they otherwise would be.
Rather than injecting drugs into the body, polygraph tests attach instruments like cardio-cuffs or sensitive electrodes to the suspect (while being questioned) and measure variables such as blood pressure, pulse rate, respiration, etc.

SC’s Guidelines in Selvi vs State of Karnataka (2010):

Taking into consideration the international norms on human rights, the right to a fair trial, and the right against self-incrimination under Article 20(3) of the Constitution, the court said that -
- A forcible intrusion into a person’s mental processes is an affront to human dignity and liberty.
Therefore, the guidelines for the administration of polygraph tests published by the NHRC in 2000, must be strictly followed.
Such tests cannot be administered without the subject’s consent, which must be obtained before a Magistrate.
Those who volunteer must have access to a lawyer and have the physical, emotional, and legal implications of the test explained to them by the police and the lawyer.

What is the Evidentiary Value of Such Tests?

The results of narco-analysis tests are not considered “confessions” since those in a drugged-induced state cannot exercise their choice in answering questions put to them.
However, the SC clarified that any information or material that is subsequently discovered with the help of voluntary administered test results can be admitted, in accordance with the Evidence Act, 1872.
Thus, if an accused reveals a physical piece of evidence (like a murder weapon) and the police later find that evidence, the statement of the accused will not be treated as evidence, but the physical evidence will be valid.

Legal Position before the SC Ruling:

In 2006, the Madras HC observed that since the accused did not come forward with the truth, the scientific tests resorted to by the investigating agency did not “amount to testimonial compulsion”.
In 2008, the Delhi HC said that narco-analysis tests “do not suffer from any constitutional infirmity” and are a “step in aid of investigation”.

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