Why CBI arrested Sandip Ghosh, RG Kar hospital ex-principal. Who are 3 others?

The Central Bureau of Investigation on Monday arrested Dr Sandip Ghosh, former principal of RG Kar Medical College and Hospital in Kolkata, for his alleged involvement in financial misconduct at the establishment.
Within an hour after Sandip Ghosh was arrested, CBI officials picked up his security guard and two vendors who used to supply materials to the hospital where the body of a woman medic, who was raped and murdered, was found on August 9.
The three persons arrested by the CBI are Sandip Ghosh’s security guard Afsar Ali Khan and two hospital vendors – Biplav Singha and Sumon Hazra.
On August 23, the Calcutta high court ordered the transfer of the investigation into the alleged financial irregularities at hospital from a state-constituted Special Investigation Team (SIT) to the CBI.
The direction came in response to a petition by former deputy superintendent of the facility Dr Akhtar Ali, who sought for a probe by the Enforcement Directorate (ED) into multiple counts of alleged financial misconduct at the state-run institute during the tenure of Sandip Ghosh.
Sandip Ghosh was questioned for the 15th day at the CBI’s Salt Lake office over the alleged rape and murder of a 31-year-old woman trainee doctor at RG Kar hospital on August 9. He was later escorted to the CBI’s Nizam Palace office in Kolkata which houses the agency’s anti-corruption wing and was shown as arrested.
This is the second arrest in the ghastly RG Kar crime fallout scenario that took place 24 days after the crime was committed. Earlier, a Kolkata Police civic volunteer, Sanjay Roy, was arrested by the Kolkata Police and handed over to the central agency in connection with the medic’s alleged rape and murder.
(With inputs from agencies)