The police too have started the investigation in the case by registering cases under the sections of rape and murder.

Based on CCTV footage within the hospital campus, one person identified as Sanjay Ray has been taken into custody by the investigation officials. However, police have declined to divulge further details about him.

Sources added that the preliminary postmortem report also suggests that the victim house staff, also a second-year post-graduation student with R.G Kar Medical College & Hospital, had to go through a sort of trauma for quite some time and she was probably strangulated to ensure her death.

As per the preliminary postmortem report, there were injury marks on the private parts of the victim’s body, besides a broken collarbone.

However, more details regarding the cause of death will surface only after the final post-mortem report is available, sources said.

The police have already recorded the statements of some of the fellow house staff and doctors of the victim. The investigating cops, sources said, have got hold of the mobile phone of the victim and they are checking the call details to get further clues about the incident.

Kolkata Police have already formed a special investigation team (SIT) under the leadership of the joint commissioner of police (crime) Murli Dhar to probe the case. Chief Minister Mamata Banerjee has given instructions to the city police commissioner Vineet Kumar Goyal to ensure that those behind the incident are arrested at the earliest.

Meanwhile, the house staff of the RG Kar have started a cease-work there to protest against the incident demanding a judicial probe into the matter. However, the emergency department of the hospital has been kept out of the ambit of the crease-work.