The accused in the alleged rape case at the Indian Institute of Management-Calcutta campus has admitted to purchasing sleeping pills from a nearby pharmacy, which he had mixed with cold drinks and drinking water offered to the woman before committing the crime, a senior police officer said on Monday.

Police, however, have found several discrepancies in the statements of the accused student of the IIM-Calcutta, he said.

"The accused had admitted to having bought sleeping pills and spiked the cold drinks and drinking water which he had offered the woman when she was there. But he could not clarify what the real intention was behind doing all these to a woman who went to him for counselling. He is not answering this question," the officer said.

Circumstantial evidence led to the discovery that the survivor, after consuming the cold drink, went to a room in the boys' hostel where the alleged crime took place, he said.

"The accused after committing the crime, rang up one of his friends and narrated the entire crime. During the conversation, he was loitering in the verandah in front of the room where the crime took place," the officer said.

Talking about the rape survivor, the officer said, there was confusion about whether she was truly a psychologist or not.

"She could not place any documents supporting her qualifications as a psychologist. She has not disclosed which institution she attended. We are yet to get information about her chamber and any prescription having her name and other details," he said.

Talking about the "contradictory" statement of the father of the victim, police said they were also trying to find out whether the family was "under pressure" to change the statement or not.

They were also investigating whether there was any financial transaction behind this change of statement of the victim's family, he said.

Police have constituted a nine-member special investigation team (SIT) to probe the alleged rape of a woman by a student at the IIM-Calcutta hostel.

The team is led by an assistant commissioner from the South West Division, they said.

The alleged incident took place in a boys' hostel of IIM-Calcutta on Friday, and the accused student was arrested the next day based on an FIR lodged by the woman at Haridevpur Police Station.

A court here has remanded the student to police custody till July 19.

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