A local court here on Sunday sent former principal of RG Kar hospital Sandip Ghosh and Tala police station officer-in-charge Abhijit Mondal to CBI custody till September 17, an officer said.

Both Ghosh and Mondal were produced before a court here by the central agency in connection with the rape-murder of a doctor at the state-run hospital.

"We have got their custody for three days till September 17. Now, both will be questioned together. The duo has played vital roles in the RG Kar case," the officer told PTI.

The CBI, probing the case, had on Saturday evening arrested Mondal and added charges of evidence tampering against Ghosh, who is currently in judicial custody in a corruption case related to the RG Kar hospital.

Mondal also faces accusations of tampering with evidence, delaying registration of the FIR, and other related offences, according to the officer. The RG Kar Medical College and Hospital falls under the jurisdiction of Tala PS.

The police officer was held after he "failed to provide satisfying answers" during questioning by the CBI officers on Saturday.

The CBI claimed in court that "there could be a bigger conspiracy" and that both Ghosh and Mondal had played some "vital roles" in this crime.

The two were in touch with each other, and the former issued instructions to the policeman on how to proceed with the rape-murder case.

Mondal was informed about the death of the doctor around 10 am on August 9, but the FIR was lodged around 11 pm, the CBI said.

Both of them tried to "downplay the incident" as well as "shield" the heinous crime, it said in court.

The police should have treated it as a suo motu case at the outset, since it's a rape-murder incident, the central probe agency said.

The CBI arrested Ghosh on September 2 in connection with financial irregularities at the hospital.

The body of the postgraduate trainee was found in the seminar hall of the state-run hospital on August 9. To date, three persons have been arrested in connection with the rape-murder case.