The rape and murder of the 31-year-old postgraduate trainee doctor has sparked many questions.

So far, the police investigation has focused on one suspect, civic volunteer Sanjay Roy, who has been arrested. The Special Investigation Team (SIT) of Calcutta Police questioned four other junior doctors (three doctors and one intern) on Monday. They had allegedly ordered food through an online delivery system and had dinner with the victim at the incident spot on Thursday.

But many have been asking, for instance, how such violence can be perpetrated in a government hospital without anyone knowing anything. The clampdown by the investigators and the leak of selective information has led the protesters to question whether there is a cover-up on.

Here are some of the unanswered questions in the case so far:

1. The preliminary inquest report suggests injuries in her neck, left leg and ankle, and right hand ring finger. Though the nature of the injuries – whether superficial, deep cut wounds or fractures - was not mentioned. The police have denied that the victim's collar bone or pelvic bone was broken. What is the exact nature of her injuries? What caused them?

2. The nursing station at the ward is reportedly close to the seminar hall where the incident took place. How can a doctor be brutally raped and murdered and no one hear anything?

3. Was the victim sedated? What does the autopsy report say about it?

4. Was she gagged when the crime was committed?

5. Was she sexually assaulted after she was killed or before? Why aren’t the police forthcoming?

6. Apart from Roy, were there any other person/s involved in the crime? Is it possible for one person to commit such brutality?

7. Is the Calcutta Police’s special investigation team certain no second or third person was involved?

8. An audio tape is going around among a section of the students. The tape claims an intern could be involved. The Trinamul leader Kunal Ghosh had shared the audio clip on his X handle on Sunday. Has the Calcutta Police tried to verify the audio tape, confirm the identity of the “intern” and interrogate him?

9. The Telegraph Online had learnt Roy had a history of misbehaving with doctors in a drunken state. Was there any complaint filed against him? If yes, why didn’t the authority take any action against him?

10. Was the former principal Sandip Ghosh/administration unaware of Roy’s drunken conduct on the campus?

11. Why was no action taken against Roy in a domestic violence case filed against him at the Kalighat Police Station, accusing him of assaulting his three months pregnant wife, two years ago?

12. Did the police and the RG Kar Medical College and Hospital authorities make any attempts to check the antecedents of Roy?

13. Why are civic volunteers on guard duty allowed to have access to any and every part of the hospital building?

14. Why wait for seven days if CBI will ultimately take the case? Will a deadline not hamper the quality of the investigation?

15. Why is the Mamata Banerjee government keen on reinstating the controversial former principal Sandip Ghosh, who was made the principal of Calcutta’s National Medical College within hours of his resignation as principal of RG Kar?