Police have since registered a case of unnatural death and launched investigations.

'We suspect he was mowed down by a speeding train although we cannot deny or confirm if it was an accident or a case of suicide,' a police official said.

'We are sure our brother was not suffering from any kind of depression other than ragging,' Gobind said.

There were no immediate comments from the college authorities.

Friends of Chintumoni said he left the hostel early Sunday, saying he would visit a nearby town to buy some books.

Earlier Friday, nine students of the prestigious Dibrugarh University were suspended for allegedly ragging juniors.