The Central Bureau of Investigation on Friday questioned former principal of RG Kar Medical College and Hospital Sandip Ghosh but did not come out with any fresh update on the probe related to the rape and murder of the young doctor at the hospital.

Ghosh has been questioned by the CBI around 15 times for long hours since the day the case was handed over to the central agency by the Calcutta High Court.

The case was transferred amid allegations that Kolkata Police was trying to shield the “real culprit or culprits”.

Kolkata Police had arrested a civic volunteer named Sanjay Roy for the alleged offense.

After the CBI took over the case, the central agency has not been able to arrest anyone in connection with the case.

A senior CBI officer said they will act only based on evidence.

“There could be a public view on the matter. The reality and the evidence could mean something different from the popular notion,” said the officer.

Till now, the CBI has questioned more than two dozen witnesses, conducted polygraph tests on around 10 people reportedly connected with the case but has not made any formal detentions or arrests.