The deceased first-year student of Jadavpur University was paraded naked in the corridor of the main hostel's second floor, minutes before he fell off from there and died, Kolkata Police's initial probe has revealed.

Investigators have also found that the teen was "sexually molested" and the arrested 12 people, including present and former students of the varsity, "had played active roles" in the entire episode, leading to the Nadia teen's death, a senior police officer said on Tuesday.

"The teen was definitely ragged and sexually molested. He was paraded naked in the corridor after he was forced to undress in room no. 70. We have evidence," the officer told PTI.

Kolkata Police investigators have got hold of a WhatsApp group created by one of the arrested accused, he said, adding, it was done to "misdirect cops".

"Probe also revealed that those arrested had planned to misdirect police so that the ragging part could be concealed," the officer said.

On Tuesday, police questioned the cook of the hostel to find out more about the August 9 incident, he said.

Two other students of the varsity have been summoned to appear before the investigators for questioning in connection with the probe.

The teen died after falling from the second-floor balcony of the main boys' hostel near the campus on the night of August 9.

His family has alleged he was a victim of ragging and sexual molestation.