Kolkata doctor rape-murder: What is a polygraph test and how it can solve puzzle pieces of RG Kar hospital horror
Times of India | 23 August 2024
NEW DELHI: CBI has obtained consent to conduct polygraph tests on Sandip Ghosh, ex-principal of RG Kar Medical College and Hospital and four of the victim’s colleagues.
The investigation is focusing on the 22 minutes between two calls made to the victim’s family on August 9 — the first at 10:53 AM stating she was unwell and the second at 11:15 AM reporting her death by suicide.
Investigators hope the polygraph tests will help piece together the victim’s final moments.
However, while the test measures physiological responses, it is not admissible in court without formal consent from the accused.
What is a polygraph test?
A polygraph test, commonly called a lie detector, tracks physiological responses such as blood pressure, heart rate, respiration and skin conductivity during questioning.It requires the accused's formal consent before a judicial magistrate to be administered.However, senior advocate Milon Mukherjee points out that the results are not admissible in court, as the law prohibits forced self-incrimination.
How is a polygraph test conducted?
A polygraph test begins with a pre-test interview where the examiner gathers information and develops diagnostic questions. The examinee is then introduced to the process and questions.A ‘stim test’ follows, where the subject is asked to lie intentionally and the examiner claims to detect it.The main test involves multiple charts being collected as questions are asked, with responses analyzed based on the subject’s physiological reactions.However, polygraph tests are not entirely reliable, as scientific and government bodies acknowledge their potential for inaccuracy in determining truthfulness.Why is it necessary in RG Kar Rape-Murder case?
A CBI officer revealed that former RG Kar principal Sandip Ghosh stated he was informed at around 9:15 AM on August 9 that an ASI had discovered the body with Tala police being alerted by 9:45 AM and a police complaint filed at 10:10 AM.
However, when the police arrived at the hospital, Ghosh was not present. Ghosh also mentioned that the victim’s parents received the first call at 10:53 AM, informing them of her condition, followed by another call at 11:15 AM reporting her death by suicide.
Investigators, dissatisfied with Ghosh’s account, are examining his call records to understand what occurred during the 22-minute gap between the two calls.
The CBI has also requested court approval for a polygraph test on Sanjay Roy, the prime suspect, with a decision expected by Friday evening when Roy appears in court.