CBI gets approval to conduct polygraph tests on Sandip Ghosh, ex-Principal of RG Kar & 4 others

A special court in Kolkata has granted the Central Bureau of Investigation (CBI) permission to conduct a lie detector test on Dr Sandip Ghosh, the former principal of RG Kar Hospital, where a 31-year-old trainee doctor was tragically raped and murdered.

The court also approved polygraph tests for four other medical professionals who were colleagues of the victim and were present with her on the night of the crime.

CBI sources have confirmed that the investigation team plans to perform polygraph tests on five individuals as part of their inquiry. These tests are designed to determine the credibility of the statements provided by those undergoing the examinations.

Earlier, on August 19, the team had received approval to conduct a polygraph test on Sanjoy Roy, the primary suspect in the case. This decision has prompted the Calcutta High Court to postpone the next hearing until August 29.

Sanjoy Roy, aged 33, stands accused of assaulting and murdering a 31-year-old second-year trainee doctor in the early hours of the incident.

Roy, a civic volunteer, was arrested the day after the doctor's body was discovered in the seminar hall of the hospital on August 9.

Earlier developments in the case included revoking Dr Ghosh's transfer to Calcutta National Medical College and Hospital, which came amid widespread protests following the unsettling incident. The ex-principal had resigned from his position at R.G. Kar Medical College and Hospital on August 12, shortly after the young doctor's body was discovered in the hospital's seminar hall on August 9.

What is a polygraph test?

A polygraph test, commonly called a lie detector test, measures an individual's physiological responses while responding to questions. According to the American Psychological Association, this test seeks to determine whether a person committed a crime, although it does not measure honesty directly. Instead, the assessment relies on the analysis performed by the polygraph operator.

The polygraph machine records physiological indicators, including heart rate, blood pressure, respiratory changes, and perspiration levels during questioning. Sensitive instruments such as cardio-cuffs or electrodes are employed to monitor these responses, with a numerical value assigned to analyse whether the individual is truthful, deceptive, or uncertain.

How will the lie-detector test help the CBI?

In Roy's case, the polygraph test results could clarify inconsistencies in his statements and alibis. Investigators may identify indications of deceit by evaluating physiological responses that deviate from baseline levels during questioning.