In a significant development, the CBI on Saturday slapped charges of rape and murder charges against former principal of RG Kar Medical College and Hospital Sandip Ghosh, currently in judicial custody in a corruption case, an official of the probe agency said.

The agency also arrested Abhijit Mondal, the officer in charge of Tala Police Station, for his alleged involvement in the rape and murder of an on-duty woman medic in the RG Kar Hospital, he said.

The hospital is under the jurisdiction of Tala Police Station.

Three persons have so far been arrested in connection with the rape and murder case.

On August 9, the semi-nude body of the woman postgraduate trainee was recovered from the seminar hall of the hospital.

Mondal, who was on Saturday questioned by the CBI officers at their CGO Complex office here for several hours, was arrested in the evening after he failed to give them satisfying answers.

He has been arrested on charges of destruction of evidence and delay in lodging the FIR, among others.

"The policeman has been questioned eight times earlier and every time he gave different versions. He has been arrested and will be produced in the court tomorrow," the CBI officer told PTI.

Earlier, one civic volunteer was arrested by the Kolkata Police in connection with the rape and murder case which is now being investigated by the CBI on an order of the Calcutta High Court.

The central agency arrested Ghosh on September 2 in a case of financial irregularities at the hospital.

CBI had applied in court seeking the remand of the Ghosh. The court has asked the jail authorities to produce him for CBI custody, the official added.