The legal scenario around Narco analysis and polygraph tests in India

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The most sensational news at present is of the Shradha Walker murder, Aftab Poonawalla who is the prime accused in that case is now about to take the polygraph and narco analysis test to dig out the truths in the miser case.

The Delhi Police took the polygraph test and narco analysis for the prime accused Aftab Poonawala to know the entire details of the murder and the timeline of the murder to crack up the case

Generally, these tests are not considered genuine as it involves inhumane practices and reduces the quality of the investigation process but if the accused is not cooperating with the investigation then the police take these tests as the last option to know the facts in the case. This Nacro analysis and polygraph tests are commonly known as DDT’s Deception Detection Tests to crack up the inch-to-inch information

A few months back in another sensational murder case of a 19-year-old Dalit Woman in Uttar Pradesh who died in Delhi hospital while undergoing medical care; the government of Uttar Pradesh went to conduct the polygraph and narco test.

These tests are done to know the facts of the issue so they present the physical body in the test so many systems of the body react and are involved in this process when the test is going on.

The physical body should maintain the balance with the mental condition of the body so that if the person is telling the truth, If the person is lying then the physical body and mental state of the body go in different directions and the lie can be dexter easily

Narco Analysis Test

This test was started during world war 2. At that time it became a widespread topic among all the countries.

While performing this test the accused takes the chemical Sodium Pentothal which is commonly called truth serum. When the accused takes this serum he goes to a drowsy state of mind and complete vision and thinking become normal with a certain point of truth-telling.

Generally, it’s a common fact that when someone is in sedated dosing his mind works completely neutral so that the person reveals the facts

Brain Mapping Test or P-300 Test

Brain mapping test reads if the person's state of mind thinking is normal or abnormal in condition if it’s normal then the mapping is with the equal state if a person lies or tries to hide the truth it gets changed and becomes high and lows of mapping. After the test got reported test gives a clear idea to investigating officers about whether the revealed facts of the accused are true or not

Critical analysis 

As of now the status of these tests can’t be completely taken into consideration as there is a lack of scientific evidence that these are accurate.

These tests are still in debate. It can not be concluded as proper information. 

For finding some facts and truth findings the agencies which do investigations are opting this type of investigation as an alternative to general investigation methods so that time can be consumed and also the level of torturing the accused gets reduced.

Normally in our country, illiteracy is high. These tests can show adverse effects on the common people who lack legal knowledge.

The legal scenario around these tests: 

As per the legal system of our country conducting these tests are currently in legal status. Cops have to give reasoning as to why this test is conducted and can proceed further with the investigation. But the acceptance of the accused is compulsory for performing this test

In the case of Selvi & Ors vs State of Karnataka & Anr case 2010, the Top Court noted that no lie detector tests must be monitored or moved “except based on the consent of the accused”. The court continued and strongly said that the accused or person undergoing this type of test must have access to an advocate. 

Before undergoing these tests the consequences of the test must be informed to the accused and the legal implications must also be informed then only this test can be performed. The apex court in earlier verdicts strongly noted that the police should perform this test without violating human rights. Police must follow the NHRC guidelines.

Police must take the permission of the judicial magistrate before conducting these tests.

The answer to these tests can’t be considered confessions. Because the accused takes drugs and his condition cannot be completely normal and the accused has the choice to answer or not. A harsh investigation for getting answers is a violation of the rule.

During the test, any material information given by the suspect cannot be considered a statement. For suppose if the suspect says that something is at some place and after that cops found it in that place then in court it is considered as a piece of evidence, not a statement.

It is mentioned in the Indian constitution article 20(3) that a person cannot be made a witness against himself.

In the 1997 apex court’s case of D.K. Basu vs. The State of West Bengal case, it was noted that if these tests are performed against the will of the accused then it is considered a cruelty act of police; the top court strongly said such acts are against the right to life and personal liberty.

As per the Indian Evidence Act of 1871 findings of these tests can not be considered evidence. 

Some sensational investigations through these tests in our country:

The rape case of Unnao: 

Central Bureau of Investigation asked the court to perform DDT’s on both of the accused who took part in driving the vehicle which was carrying the victim of Unnao rape in the state of UP. 

2008 Noida double murder case: 

Both of the accused in this case were the parents of the victim Arushi Talwar. Police conducted the polygraph test during the investigation.

As of now, no proper scientific proof is there to accept the complete accuracy of these tests. But these are opted by the investigative agencies to crack the case easily and effectively understanding the case.


These tests cannot be considered proper findings of evidence as they lack scientific proof. But, these tests can play a crucial role in finding the truth and cracking the case with less difficulty because some sort of clues will be known to the investigation agencies. Nowadays our country must bring and develop the methods of technology in fact-finding otherwise lengthy investigation processes goes on and the intensity of the crime gets reduced day by day and justice cannot be served speedily.


1. What is Narco Analysis and Polygraph Test?
2. What is the legal scenario surrounding Narco Analysis and Polygraph Tests in India?
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