Mamata Banerjee on Monday met the grieving parents of the junior doctor who was raped and murdered at RG Kar Medical College and Hospital and gave the police till Sunday to solve the case, failing which the probe would be handed over to the CBI.

The chief minister made the announcement after stepping out of the victim’s home on the city’s northern fringes.

She said the family suspected the involvement of more than one person. She also spoke of the possibility of “people inside” having a hand.

The police called seven junior doctors who were on duty the night of the crime and a food delivery boy, believed to have served the victim her last meal, to their Lalbazar headquarters. They were allowed to leave after questioning.

Thousands joined a 4.5km protest march from Medical College Kolkata to RG Kar. The participants included many young women and elderly people. The length of the procession stretched almost 2km.

RG Kar principal Sandip Ghosh tendered his resignation and was later transferred to Calcutta National Medical College as principal. He has been the subject of a public furore for failing to provide basic security and allegedly blaming the woman for what had happened to her. Ghosh has denied the allegation.

“If someone from inside (the hospital) is involved, if there is suspicion on anyone among the (victim’s) friends, the police should call and question all of them,” Mamata said.

“And if they fail to complete the probe by Sunday —because people inside are also there — we will not keep the case with us. We will hand it over to the CBI.”

Police commissioner Vineet Goyal was by Mamata’s side as she made the announcement.

The police confirmed they were probing the parents’ allegation about the possible involvement of “insiders” and the alleged problems the young doctor had had with some colleagues.

Mamata Banerjee speaks to reporters after meeting the parents of the murdered postgraduate trainee at their residence in Sodepur on Monday. Picture by Ankit Mukherjee

Mamata said the hospital official who phoned the family to inform them about the incident on Friday morning should also be called and questioned. The family has alleged they were informed over the phone that their daughter had committed suicide.

Two senior hospital officials — the head of the department of chest medicine and the assistant hospital superintendent — have been summoned to Lalbazar on Tuesday.

A police sniffer dog was taken to the seminar room — the crime scene — on Monday evening.

Mamata reaffirmed that the prosecution would seek the death sentence.

“I was in Jhargram that day (Friday). But the moment I learned (about it) from the police commissioner, I told him this was a very despicable incident, a very painful incident,” she said.

“We want the case heard in a fast-track court…. We will demand capital punishment,” she added, while referring to “the brutality with which she was assaulted and killed”.

Mamata expressed surprise that the incident happened while nurses andsecurity guards were at the hospital.

A senior officer said all the staff and doctors who were on duty in the building where the crime occurred would be called for questioning.

Of the seven on-duty junior doctors called, four had had dinner with the victim while the other three had met the four earlier in the day.

The police said they had seized CCTV footage for the30 days preceding the crime from several buildings inthe hospital to look for any suspicious movements.

The strength of the special investigation team has been increased.

Samples extracted from the arrested accused, Sanjay Roy, a civic volunteer with the Kolkata Police, have been sent for DNA sampling tobe matched with skin and semen samples found on the victim’s body.

Samples from the woman’s body have been collected to ascertain the number and identities of the people involved.

The police formally confirmed on Monday that the post-mortem did not show a fracture in the woman’s collarbone or pelvic bone, contrary to what some reports had suggested.

From Roy’s call detail records, the police found a woman’s number to which he had made multiple calls.

“The woman has been contacted. She says Roy met her when she went to the hospital for some treatment, and helped her. But after that he started disturbing her,” an officer said.

Mamata underlined her trust in Kolkata Police, calling them the “best police force in the world”.

But she said she was ready to hand the case over to the CBI “for the satisfaction of the people” if the city police were unable to carry out the probe properly.

“I have been saying this from the beginning. Their (the CBI’s) success rate is very low. Tapasi Mullick was killed in Singur, but justice has not been delivered,” she said.

“When 14 people were killed in Nandigram and 10 people went missing — they have not returned till now. Rizwanur’s case was also in the hands of the CBI. Rabindranath Tagore’s Nobel (medallion) theft too was probed by the CBI. But people have not got any justice.”