CBI to conduct polygraph test of accused. How accurate is it? – Firstpost

On Monday, the Central Bureau of Investigation (CBI) was granted permission to conduct a polygraph test of prime accused Sanjay Roy in the brutal rape and murder of a postgraduate trainee doctor at Kolkata’s RG Kar Medical College and Hospital.

Due to this development, the High Court postponed the case’s next hearing until August 29, as per The Economic Times.

The accused, Roy, who is now in the agency’s custody, had his psychoanalysis test conducted earlier on Saturday by the CBI.

The Kolkata Police had arrested him a day after the 31-year-old victim’s body was found in the seminar hall of the chest department of the Hospital between 3 am and 5 am on Friday.

But what are polygraph tests, and how do they help in an investigation? We explain.

A polygraph test

A polygraph test, sometimes referred to as a lie detector test, is a scientific technique that evaluates physiological reactions that could reveal whether an individual is telling the truth or lying, as per News18.

When a person answers questions from an operator, the polygraph machine records many physiological indications, including heart rate, blood pressure, skin conductivity, and respiration.

Then, based on the data, it is determined if the individual is telling the truth or not.

According to Britannica, the lie detector has been a part of police interrogations and investigations since 1924. However, psychiatrists remain divided on its efficacy, and the results are also not always judicially acceptable.

Also read: Kolkata rape-murder case: The many questions parents of the victim are now asking Mamata Banerjee

Process of conducting the test

A polygraph test subject has four to six sensors linked to them, according to a report by HowStuffWorks.

A polygraph is a device that records several signals from sensors on a single moving paper strip, or “graph,” or “polygraph.”

Typically, sensors capture:

• The individual’s breathing rate

• The person’s pulse rate

• The individual’s blood pressure

• The perspiration of a person

• A polygraph will sometimes record arm and leg movement as well.

Before the polygraph test starts, the interviewer poses three or four straightforward questions to set the standard for the subject’s signals, as per News18.

The actual questions are then posed by the polygraph examiner.

Throughout the questioning, every signal made by the subject is captured on the moving paper.

The rules

In the 2010 Selvi v. State of Karnataka and Anr case, the Supreme Court declared that no lie detector test should be conducted without the accused’s approval, the report said.

It is mandatory for volunteers to have legal representation and to be informed by police and the lawyer on the psychological, physical, and legal ramifications of the test.
Article 20(3), the right against self-incrimination, which stipulates that an accused person cannot be made to testify against themselves, was referenced by the Supreme Court.

The Supreme Court held in the 1997 case of DK Basu v. State of West Bengal that the forcible administration of the narcotics test and polygraph was in violation of Article 21 of the Constitution, which guarantees the right to life and liberty, and thus constituted cruel, inhuman, and humiliating treatment.

It can also be against the Right to Privacy, which is a part of the Right to Life.

Although the test findings cannot be regarded as “confessions,” any data or information obtained from a voluntary test of this kind may be accepted into evidence.

The Indian Evidence Act of 1871 prohibits the use of the test results as admissible evidence.

Also read: Kolkata rape-murder case: Why doctors in India are in urgent need for a central protection law

Accuracy rate

Both polygraph and narcotics tests are controversial in the world of medicine and have not been shown by science to have a perfect record of success.

These tests are occasionally viewed as a “softer alternative” to torture or the “third degree” in terms of getting the truth from suspects, but recently, investigating agencies have attempted to use them in their work.

The estimated accuracy of the polygraph test stands at 87 per cent, as per HowStuffWorks.

The report also cited the National Research Council that there is evidence suggesting that lie detector results can also be fabricated.

Usefulness in the latest case

Due to its ability to provide information about a suspect’s honesty, the polygraph test can be quite helpful to the investigation.

The test can be used to confirm if Roy’s claims and alibis are consistent, explained ET. Investigators can ascertain whether any inconsistencies in his account might point to deception by evaluating his psychological responses to certain questions regarding the crime.

Investigations can focus more precisely on the use of test results.

About Sanjay Roy

The second-year postgrad had gone to an empty seminar room alone that evening to catch some sleep after working a 36-hour shift. There is no on-call room at the hospital.

The following morning, August 9, her partially clothed body was discovered there with several injuries.

The primary suspect is Sanjoy Roy, a Kolkata Police volunteer who served as a civil servant and was given access to every department while he was stationed at the police outpost at RG Kar Medical College and Hospital.

According to NDTV, CCTV footage showing him entering the building where the doctor’s body had been found murdered served as the basis for his arrest. A Bluetooth headset found next to the victim’s body was seen on his neck in the CCTV footage. It turned out that his phone had been linked with it.

Roy reportedly confessed to the crime shortly after police began questioning him, according to local media. He had nonchalantly informed the cops, “Hang me if you want,” according to the reports.

According to the authorities, Roy was a “womaniser” and had been married at least four times.

As per a PTI report, the accused has received training in boxing and has developed relationships with a few senior police officers over the years.

He was transferred to the Kolkata Police Welfare Board and assigned to the RG Kar Medical College and Hospital police outpost.

The medical community is seeking justice and strict regulations to safeguard the fraternity in response to the brutal rape and murder of the doctor.

With inputs from agencies