As part of this, over 20 women are alleged to have been taken to Narain’s residence in Port Blair during his year-long tenure and some of them are said to have got jobs in lieu of being sexually exploited, investigators have been told.

Narain is expected to appear before the SIT on October 28, the last date set for his appearance by the Calcutta High Court.

Senior police officers in Port Blair confirmed to The Indian Express that CDRs (call data records) and cell phone tower locations of mobile phones of the two bureaucrats, both suspended, and of the 21-year-old “match” the alleged sequence of events, as provided by the woman.

Sources have also confirmed that the hard disk of the DVR (digital video recorder) of the close circuit (CCTV) camera system installed at the Chief Secretary’s house was first erased and, subsequently, the DVR was removed at the time of his transfer from Port Blair to Delhi in July.

It is understood that a PWD official and a local CCTV expert have given their testimonies confirming the alleged destruction of electronic evidence.

While arguing for denial of transit bail to the bureaucrat, the A&N prosecutor had, before the Delhi High Court, said that the statement of the victim had been corroborated by a “protected witness” and by electronic evidence. The October 20 order also states that there are “instances of tampering the evidence by the petitioner (Narain).”

Denying the charges, Narain, in letters to the Home Ministry and A&N administration, has said there is a “conspiracy” against him and claimed that he has “specific materials which demonstrate the fake nature of the case.”

He has challenged his presence in Port Blair on one of the two dates given in the FIR and cited air tickets and appointment schedules to show his presence in New Delhi. On Wednesday, his lawyers moved a petition in the Sessions Court apprehending destruction of that evidence.

However, the 21-year-old’s family members are understood to have told the police there was a mix-up in the dates given by the woman and have since clarified this in their testimonies to the SIT.

When contacted in New Delhi, Narain said he could not comment on the latest developments since the matter was sub judice. His lawyer, who filed the latest petition in Port Blair today, declined to comment.

A day after The Indian Express reported on the allegations, Narain was suspended on orders of the Home Ministry on October 17 and has got interim bail until November 14. Rishi has also been suspended and non-bailable warrants have been issued in his name after his bail plea was rejected in Port Blair.

On October 18, a team of the A&N police, accompanied by officers of the Delhi Police, reached the residence of Narain in New Delhi, with a notice for him to appear before the SIT. While he was not at his residence, “electronic” evidence, including laptops and mobile phones, were collected by the police team and taken to Port Blair for forensic examination. The missing DVR player was not among the evidence traced by the A&N police.

When contacted, A&N’s Director General of Police Neeraj Thakur told The Indian Express here that the immediate priority is to pursue the gangrape allegation for which the 21-year-old lodged an FIR on October 1.

“We have formed an SIT and are confident about the oral and electronic evidences collected by them. As the investigation progresses, we are preparing to present a strong case in court,” Thakur said.

Crucial to the probe are testimonies (some recorded under Section 164 CrPC) to the SIT by members of the former Chief Secretary’s staff including drivers, cooks and other househelp. At least one of them has been listed as a “protected witness” by the SIT for fear of his security.

One staff member said: “I was threatened by the then Chief Secretary about danger to my life if I ever spoke about the (women) guests that visited the house.”

The staff member, among others, spoke to The Indian Express and alleged that between 20-25 women were escorted by him to the former Chief Secretary’s house with the pattern of visits “matching” the sequence described by the 21-year-old in her original complaint to the A&N police and later in the FIR.

At least one staffer has testified to the SIT about how he would be instructed to “pick up the women,” often pick up food from a local restaurant, serve it at the Chief Secretary’s house and later be asked to drop the women off at a pre-destined place. At least two “guests” of the Chief Secretary were escorted by him to his house even after the two visits of the 21-year-old in April and May, the staffer said.

Speaking to The Indian Express, the 21-year-old woman said that she had provided “every minute detail” to the SIT. She added that on both her visits, she found the door to the kitchen locked from the outside to confine the staff inside and that it was a “driver” who served them food and snacks.

She said she was asked to “deposit” her mobile phone in a bowl placed at the entrance of the house and that Rishi and Rinku, a hotel owner who had introduced her to the Labour Commissioner – he is also absconding — warned her against speaking about the violent sexual assault to anyone.

The woman has also given the SIT an audio conversation purportedly between herself and Rinku in which the latter warns her against going public and promises her a Government job. She has since been taken by the SIT for a medical examination and to the alleged scene of the sexual assault to help investigators reconstruct the events. She is said to have identified the car in which she was taken.

“I was repeatedly assured by the Chief Secretary and the Labour Commissioner that a job for me was confirmed. Then all this happened and when Rishi told me that the Chief Secretary has been transferred and there was no chance of a job, I decided to go to the police” she said.

Her family members said they were now proposing to move the Supreme Court for cancellation of the former Chief Secretary’s interim bail, granted by the Calcutta High Court.

SIT officials said they have collected “all possible, detailed” evidence in the case and will be ready to file a chargesheet in the next few weeks.

In her complaint, the woman said that in search of a job, she was introduced to Rishi through Rinku, the hotel owner, and Rishi took her to Narain’s residence. There, she said, she was offered liquor which she refused and was assured Government employment . Subsequently, she alleged, she was brutally and sexually abused by the two men.

Two weeks later, she alleged in the complaint, she was again called at 9 pm by them to the Chief Secretary’s residence and the assault was repeated.