Prof (Dr) Sandip Ghosh, the controversial former principal of the R G Kar Medical College Hospital, and five others, including four junior doctors (two first-year postgraduate trainee (PGT) doctors, one house staff and an intern of the teaching hospital) on Monday underwent second round of polygraph tests conducted by the Central Bureau of Investigation (CBI) probing the heinous rape and murder case of a 31-year-old woman PGT doctor happened in the chest medicine department of the same government medical teaching institute on 9 August.

The central investigating agency on Saturday had conducted the first round of polygraph tests separately on the same six suspects at the CGO Complex.

CBI had also conducted polygraph test on the prime accused Sanjay Roy, a civic volunteer of the Kolkata Police (KP) at the Presidency Correctional Home on Sunday. He is the only accused arrested so far by the KP that was initially investigating the case. With the directive of the high court, CBI is investigating the R G Kar Medical College Hospital incident.

According to sources in the CBI, over the last 10 days, Prof Ghosh provided inconsistent answers during questioning, prompting officers to conduct another round of polygraph tests.

Additionally, Prof Ghosh, an orthopaedic surgeon, and former medical superintendent and vice-principal (MSVP) of R G Kar Medical College Hospital Dr Sanjay Vashisth are also being investigated by the CBI for their alleged financial irregularities within the medical institute.

On Sunday, the CBI searched houses of both Prof Ghosh and Dr Vashisth, with the former presenting files and documents at the central agency’s CGO Complex office in Salt Lake on Monday morning. Dr Vashisth appeared at Nizam Palace, where a forensic medicine department professor was also questioned.

The agency also searched 13 other locations in Kolkata and Howrah, including residences and offices of people involved in patient care and management supplies connected to the hospital.

Besides the rape and murder case, CBI, following directives of the high court, started investigation to probe alleged link of Prof Ghosh and Dr Vasisth in the financial irregularities at in R G Kar Medical College Hospital.

The court directed the central investigating agency to probe the alleged irregularities after Akhtar Ali, former non-medical deputy superintendent of the hospital, brought charges of financial scams in connection with tenders for the construction of food stalls, cafes, canteens, and urinals keeping the health department and the college council in dark.

The two first-year PGT doctors underwent the lie detection test because their fingerprints were found inside a seminar hall at the R G Kar Medical College Hospital where the medic’s body was discovered, sources said.

A special team of the CBI along with experts of the Central Forensic State Laboratory (CFSL) reached the CGO office on Saturday from Delhi.

The CBI told the Supreme Court on Thursday that there was an attempt to cover up the alleged rape and killing of the postgraduate doctor by the local police, as the crime scene was altered by the time the federal agency took over the probe.