The students reported the matter to the PU authorities, who then informed the police.

The junior student, who is from Noida in Uttar Pradesh, is staying here in the hostel.

'We have registered a case against Nandal and started our investigation,' police officer Sukhbir Rana said Sunday.

In the last academic session, nearly 25 students were involved in ragging on the PU campus. Half a dozen of them were expelled.

PU, one of the oldest universities of the country, was established in 1882 at Lahore and was shifted to Chandigarh in 1956.

The campus is spread in Sectors 14 and 25 of the union territory. There are over 10,000 students, of which 70 percent are girls, who study here in over 60 teaching and research departments.