Doctors found scratch marks on the body of Monojit Mishra, the arrested prime accused in the gang rape of a student at a Kolkata law college, a well-placed police source said on Tuesday.

The injury marks from nails are indicative of the resistance put up by the victim during the alleged sexual assault that took place inside the room of a security guard at the South Calcutta Law College on the evening of June 25, he said.

"There are signs of injuries, precisely scratch marks, on the body of Monojit. These injuries are fresh. Such injuries happen when someone faces struggle or resistance," the officer said.

Going through the phone call details record (CDR), the nine-member Special Investigation Team (SIT) of the Kolkata Police also found evidence of a conversation between Monojit and Vice Principal of the college, Dr Nayna Chatterji, the morning after the crime.

"The CDRs of the mobile phones of the three arrested accused have been cross-checked. We found that there was a call from Monojit's number to the college VP the next morning after the crime took place. We have questioned the VP twice since yesterday to know the details of their conversation," the IPS officer said.

Efforts were on to find out every detail of their telephonic conversation between the two, he said.

Police have also seized the CCTV footage of a medical shop from where one of the arrested accused purchased an inhaler for the victim during the period of her torture inside the campus, the officer said.

"Zaib Ahmed had gone to the medical store to fetch the inhaler. The owner of the pharmacy said that Zaib wanted to make half of the payment in cash and the rest via UPI, which we didn’t agree to. The accused then made the full payment online. We have taken a note of their version," he said.

PTI earlier reported that the victim in her complaint had stated that she requested her attackers to take her to a hospital after she fell ill during the torture. But after her plea was denied, she urged them to provide her with an inhaler to relieve her of the breathlessness she was suffering.

She mentioned in her complaint that Zaib, Mishra's accomplice, had fetched that inhaler which made her feel better, but only temporarily since the torture resumed after that.

On Tuesday, the investigating officers questioned six of the 16 people, mostly students, who were seen in the footage of the CCTV at the college about their activities on June 25, the officer said.

"We have prepared a list of 16 people whose presence was captured in the CCTV at the college after class hours. We are talking to them to find out whether they have seen or heard anything there on June 25," he said.

Police confirmed that digital footprints collected from the scene of the crime, medico-legal evidence found on the accused and the victim, as well as circumstantial evidence, pointed to a match with the victim’s official complaint.

Police have prayed for a further custody of 10 days for all the arrested accused at the Alipore court on Tuesday after their initial four-day remand expired.

Talking to reporters, Kolkata Police Commissioner Manoj Verma said that the investigating sleuths have collected several pieces of evidence in connection with the crime.

"The matter is quite sensitive and I will not be able to reveal details. We have arrested the three accused within 12 hours after the FIR was filed. Another person was also arrested later," Verma said.

The fourth arrested person, Pinaki Bandyopadhyay, is the security guard on duty at the time of the crime.

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