A South Korean exchange student, who ran naked in his Chinese University of Hong Kong hostel after smoking marijuana, was arrested on Tuesday morning for allegedly indecently assaulting a compatriot in the same dormitory.

At 4am, the 21-year-old surnamed Choi and a 23-year-old South Korean female student returned to the Chan Chun Ha Hostel in United College, Headline Daily reported.

It is believed the pair were earlier studying in the University Library, which is open 24 hours and a 20 minute walk from the hostel. Choi had smoked weed outside the library after they had left, the report said.

Choi, who lives on the sixth floor, was escorting the woman back to her room on the fourth floor when he suddenly took off all his clothes and tried to remove her trousers, the daily said.

The woman put up a fight, but Choi grabbed her around the throat and bit her in the forehead. The woman shouted for help and fled to her floor, the report said.

College security guards subdued the naked student, who was later restrained to an ambulance stretcher and sent for a checkup at the hospital, the daily said. The victim was also treated for her injuries.

At 8am, Choi’s roommate surnamed Nam, also a 21-year-old exchange student from South Korea, was arrested for possessing drugs after a small amount of marijuana was recovered from their dormitory room, Oriental Daily reported.