A “great nexus”, the CBI said in court on Tuesday about former RG Kar Medical College and Hospital principal Sandip Ghosh and three others.

Metro compiles what is known about the four, who were arrested by the CBI on Monday, and what is not so well known about them, based on the CBI’s submissions in the court and conversations with officers in the agency.

Sandip Ghosh, 53

Ghosh was the principal of RG Kar Medical College and Hospital on August 9, the day a junior doctor was found raped and murdered in the Emergency Building of the hospital.

He resigned as the RG Kar principal on August 12. Within hours, he was appointed the principal of Calcutta National Medical College and Hospital. The swift reinstatement triggered a public outcry and allegations that his clout was such that he could do whatever he wanted with impunity.

On August 13, while transferring the probe into the rape and murder to the CBI from Kolkata Police, Calcutta High Court sent Ghosh on “leave until further directions”.

Afsar Ali, 44

Ali was Ghosh’s “additional security guard” at RG Kar and often referred to as his “bouncer”. He had been recruited by the state health department.

In a video, which was from last year but gained online traction recently, he was heard flaunting his alleged links with “Didi” and “CM Didi” in front of senior RG Kar officials, who were querying him about his designation and the work he did. “You call Didi. Does anyone have Didi’s number?” Ali is heard saying in the video.

He also ran a cafe on the campus, allegedly a favour extended by Ghosh.

Biplab Singha, 52

Singha supplied medicines and other items to the hospital. He owns an agency called Ma Tara Traders in Banipur, Howrah.

Suman Hazra, 46

Hazra supplied medicines and medical equipment at inflated rates to the hospital.

Charges

The arrested persons have been charged with

• Cheating

Section 318(4) of Bharatiya Nyaya Sanhita (BNS)

• Forging documents

Section 338 of BNS

• Fraudulent use of original documents and criminalconspiracy

Section 340(2) of BNS

• Criminal conspiracy

Section 61(2) of BNS

• Under the Preventionof Corruption Act