What is the difference between Polygraph and Narco Analysis Tests?

Delhi Murder Case: The accused apprehended for the murdering and dismembering of Shradha Walker, Aftab Poonawalla will undergo a Narco Analysis test in order to bring out the concealed details regarding the murder.
Polygraph and Narco Analysis Tests
Polygraph and Narco Analysis Tests

Aftab Poonawalla, the accused of Shradha Walker's murder, will have to undergo a Narco Analysis test, in order to figure out the real motive behind the murder and timeline.

Narco analysis and polygraph (or lie detector) tests are often considered to be inhumane and degrading investigation practices and are only used in extreme cases of investigation, where the crime is vicious and gruesome, and the accused is refusing to cooperate with the investigation. These Deception Detection Tests (DDTs) are carried out to bring out concealed information. 

IN 2022, Adityanath led UP Government decided to conduct polygraph and narco-analysis tests of the accused and the police personnel who were involved as part of the investigation in the alleged gangrape of a 19-year-old Dalit woman,  who died while undergoing treatment at Delhi's Safdarjung Hospital.

Do you know what these tests are and are they legal? Read the article below to find out. 

Polygraph or Lie Detector Test

In this procedure, several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity are measured and recorded while a person is investigated.

It is assumed that the physiological responses of a person are different from the responses recorded when a person is lying. Each response is assigned a numerical value which concludes if a person is telling the truth, lying, or is uncertain.

In the 19th century, Italian criminologist Cesare Lombroso performed a similar test to measure the changes in the blood pressure of criminal suspects during interrogation. In 1914 and in 1921, American psychologist William Marston and California police officer John Larson created similar devices to conduct the tests. 

Narco Analysis Test

In this test, Sodium Pentothal, also known as 'truth serum' is injected into a person inducing a hypnotic state of mind, and neutralizing the imagination. 

It is believed that in the sedated state of mind, a person speaks the truth. This drug is used in higher doses as anesthesia during surgery. 

The Narco Analysis test is said to have been used during World War 2 to seek information. 

Brain Mapping Test or P-300 Test

This test measures the activity of the brain of the suspect during the interrogation to conclude whether the person is concealing any information or not. 

Key Takeaways

1- No scientific evidence has been found to date to state the success of the above-mentioned tests. 

2- These tests are contentious in the medical field. 

3- Nowadays, investigating agencies are employing these tests in the investigation as a softer alternative to torture or the third degree to find out the truth. 

4- These tests may have an adverse impact on individuals who aren't aware of their fundamental rights and cannot afford legal advice. 

Legal aspects of the tests: 

Yes, these tests are legal in India. However, the consent of the suspect is mandatory to perform the test. 

1- In the year 2010, in the Selvi & Ors vs State of Karnataka & Anr case, the Apex Court ruled that no lie detector tests should be administered “except on the basis of the consent of the accused”. The court further stated that the individual undergoing the test must have access to a lawyer. 

2- Not only this, the physical, emotional, and legal implications of the tests must be explained to the suspect in advance by the police and the lawyer. The court also stated that the ‘Guidelines for the Administration of Polygraph Test on an Accused’ published by the National Human Rights Commission in 2000, must be taken into strict consideration. 

3- Before performing the test on the subject, his/her consent must be recorded before a judicial magistrate. 

4- The results of these tests cannot be labeled as 'confessions'. This is because, in a drug-induced state, a person cannot exercise a choice in answering questions that are asked. 

5- If any information is found to be true or material is discovered via the test, it can be admitted as a piece of evidence. For instance, if the suspect reveals the location of the material during the test and if the police find the same at the said location, the material discovered will be considered a piece of evidence and not a statement. 

6- As per Article 20 (3) of the Indian Constitution, an accused cannot be forced to be a witness against himself. 

7- In the D.K. Basu vs. State of West Bengal case in 1997, the Supreme Court of India ruled that involuntary administration of these tests will lead to cruel, inhuman, and degrading treatment in the context of Article 21 or the Right to Life and Liberty. 

8- The Indian Evidence Act of 1871 does not accept the results of these tests as evidence. 

Have these tests been used in India Before?

Yes, these tests have been used in investigating the following cases:

1- Unnao Rape case: CBI sought to conduct these tests on the driver and the helper of the truck that hit the vehicle carrying the Unnao rape victim in Uttar Pradesh. 

2- 2008 Noida double murder case: Dr. Rajesh Talwar and Dr. Nupur Talwar underwent the polygraph test. The parents were accused of killing their daughter Aarushi and helping Hemraj. 

So far, no scientific evidence has backed these tests.

However, they are used by the officials of the investigating agencies to solve complicated and grievous cases. 

What is TRP and how is it calculated?

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