Narco test decoded: What is 'truth serum', to be given to Aaftab Poonawala? Are 'confessions' admissible in court?

A Delhi Court on Thursday ordered narco test for Aaftab Amin Poonawala in the bone-chilling Shradha Walkar killing case. After police moved court seeking permission for the test, Poonawalla consented, telling the judge he was aware of the consequences. 

This has put the spotlight on use of the specialised examination as an advanced tool for interrogation. Here is what a narco test means:

What is a narco test?

The narco analysis test is also known as the truth serum and has been used by investigative agencies to solve crucial cases in the past. 

The test involves the intravenous administration of a drug (such as sodium pentothal, scopolamine and sodium amytal) that causes the person undergoing it to enter into various stages of anaesthesia. 

In the hypnotic stage, the person becomes less inhibited and is more likely to divulge information, which would usually not be revealed in the conscious state.

Sodium pentothal or sodium thiopental is a fast-acting, short duration anaesthetic, which is used in lager 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”, and is said to have been used by intelligence operatives during World War II.

The term narco-analysis is derived from the Greek word narko (meaning anaesthesia or Torpor) and is used to describe a diagnostic and psychotherapeutic technique that uses psychotropic drugs, particularly barbiturates.

According to experts, during the narco test, the person's inhibitions are lowered by interfering with his or her nervous system at the molecular level. In such a sleep-like state, efforts are made to obtain probative truth about the crime. The dose of the injected substance is decided as per the person's sex, age, health, and physical condition.

The person concerned is then interrogated by the investigating agencies in the presence of doctors. The revelations made during this stage are video recorded. The report prepared by the expert is used in the process of collecting evidence. The procedure is conducted at a government hospital, after a court order permitting the same.  

Are narco and polygraph tests same?

No. In polygraph test, a device called lie detector is used that records physical phenomena such as blood pressure, pulse rate, and respiration of a human subject as he answers questions from an operator; the data is then used to determine whether or not the subject is lying. The lie detector, which has been used in police interrogation and investigation since  1924, is still controversial among psychologists and is not always judicially acceptable, Britannica explains.

Such a test is believed to have been first done in the 19th century by the Italian criminologist Cesare Lombroso, who used a machine to measure changes in the blood pressure of suspects when interrogating them.

Conditions of putting accused through narco test

According to a Supreme Court order in the Selvi & Ors vs State of Karnataka & Anr case, no lie detector test shouls be administered “except on the basis of consent of the accused”. 

Those who volunteer 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, the court had ruked.

It said that the ‘Guidelines for the Administration of Polygraph Test on an Accused’ published by the National Human Rights Commission in 2000, must be strictly followed. The subject’s consent should be recorded before a judicial magistrate, the court said.

Are narco test confessions admissible in Indian courts?

The Supreme Court ruled in the Selvi vs State of Karnataka & Anr case (2010) that results of the tests cannot be considered “confessions," but any information or material discovered as a result of such a voluntarily administered test can be admitted as evidence, reports stated.

The Supreme Court cited Article 20 (3), or the right against self-incrimination, which states that no accused can be forced to testify against himself. In the 1997 case of D.K. Basu vs. State of West Bengal, the Supreme Court ruled that involuntary administration of the polygraph and narcos test constituted cruel, inhuman, and degrading treatment under Article 21 of the Constitution, or the Right to Life and Liberty. It may also violate the Right to Privacy, which is a component of the Right to Life.

The results of these tests are not admissible as evidence under the Indian Evidence Act of 1871.

Narco and polygraph tests used in crucial cases in past

The narco analysis test was most notably used in the 2002 Gujarat riots case, Abdul Karim Telgi fake stamp paper scam, the Nithari killings case in 2007 and the 26/11 Mumbai terror attack case on captured terrorist Ajmal Kasab.  

Dr Rajesh Talwar and Dr Nupur Talwar, who were accused of killing their daughter Aarushi and help Hemraj in Noida in 2008, were given polygraph tests. A video of the narco test on their compounder, Krishna, was leaked to the media.

In August 2019, the CBI wanted to conduct polygraph and narcoanalysis tests on a former staffer of Punjab National Bank (PNB), who was in custody in the alleged Rs 7,000-crore fraud involving the absconding jewellers Nirav Modi and Mehul Choksi. The manager, Gokulnath Shetty, declined consent.

In October 2020, the UP government sought to conduct polygraph and narco tests as part of the investigation into the alleged gangrape and murder of a 19-year old Dalit woman by four men of the Thakur caste in Hathras. The victim’s family refused.