Officials stated that Sandip Ghosh, the former principal of RG Kar Medical College, was found to be "deceptive" during his polygraph test and layered voice analysis while responding to critical questions regarding the rape and murder of a female postgraduate trainee doctor.

The CBI, which is investigating the case, arrested Sandip Ghosh on September 2 in connection with financial irregularities at the hospital. The agency later also charged him with evidence tampering.

During the investigation, Sandip Ghosh underwent various voice analysis and a polygraph test. According to a report from the Central Forensic Science Laboratory (CFSL) in New Delhi, Ghosh's responses were found to be "deceptive on certain important issues" related to the case, according to officials familiar with the developments.

While the findings from the polygraph test cannot be used as direct evidence in court, they may help the agency gather corroborative evidence that can be presented during the trial, officials said. Polygraph tests assess the accuracy of statements made by suspects and witnesses by measuring psychological responses such as heart rate, breathing patterns, sweating, and blood pressure, to identify discrepancies in their accounts.

The CBI has accused Ghosh of receiving information about the rape and murder of the trainee doctor at 9:58 am on August 9 but delaying the filing of a police complaint. It is alleged that he only made a "vague complaint" later through the medical superintendent-vice principal, even though the victim had been declared dead by 12:44 pm.

During the investigation, Sandip Ghosh underwent a layered voice analysis and a polygraph test. According to a report from the Central Forensic Science Laboratory (CFSL) in New Delhi, Ghosh's responses were found to be "deceptive on certain important issues" related to the case, according to officials familiar with the developments.

While the findings from the polygraph test cannot be used as direct evidence in court, they may help the agency gather corroborative evidence that can be presented during the trial, officials said. Polygraph tests assess the accuracy of statements made by suspects and witnesses by measuring psychological responses such as heart rate, breathing patterns, sweating, and blood pressure, to identify discrepancies in their accounts.

The CBI has accused Ghosh of receiving information about the rape and murder of the trainee doctor at 9:58 am on August 9 but delaying the filing of a police complaint. It is alleged that he only made a "vague complaint" later through the medical superintendent-vice principal, even though the victim had been declared dead by 12:44 pm.

The CBI has alleged that Sandip Ghosh contacted the Officer in Charge (OC) of Tala Police Station, Abhijit Mondal, at 10:03 am and an advocate at 1:40 pm, while a case of unnatural death was registered later that night at 11:30 pm.

Mondal, who was also arrested by the CBI in connection with the case, allegedly received information about the incident at 10:03 am on August 9 but delayed reaching the crime scene, arriving an hour later. Officials claim the general diary entry (No. 542) recorded that the body of the postgraduate trainee doctor from RG Kar Medical College was found in an "unconscious state" in the seminar room of the chest medicine department, despite a doctor having already confirmed the victim was dead.

This entry was allegedly made "in conspiracy with hospital authorities and other unknown persons," intentionally including false details. Mondal's failure to file an FIR and secure the crime scene led to the "destruction of crucial evidence," officials said. He is also accused of protecting Sanjay Roy and others who had unauthorized access to the scene, possibly contributing to the tampering of evidence.

Ghosh allegedly instructed his subordinates to quickly transfer the body to the morgue. The trainee doctor was reportedly raped and murdered in the seminar hall of RG Kar Medical College and Hospital when she went to rest during her shift in the early hours of August 9. Her body, showing severe injury marks, was discovered by a doctor making rounds.

Sanjay Roy, a police volunteer, was arrested the next day after CCTV footage revealed him entering the seminar hall at 4:03 am on the day of the incident. The Calcutta High Court, on August 13, ordered the transfer of the investigation from the Kolkata Police to the CBI, which officially took over the case on August 14.