A university student who had hidden inside a toilet tried to cover a woman's head with a paper bag before sexually assaulting her, San Po Kong Court heard yesterday. Wong Chung-ka, 22, a history student at the Chinese University of Hong Kong, denied indecently assaulting the woman at the Baptist University on July 11. The 22-year-old victim, a student at the university, was washing her hands when she saw a stranger coming out of a cubicle, the court heard. She said Wong ran towards her with a paper bag and tried to cover her head with it. The court was told that when the woman fell on the ground, Wong put his hand over her mouth and indecently assaulted her. Her boyfriend, 20, rushed to help after hearing her screams. With the help of another male student he chased and caught Wong on the podium, the court heard. Defence lawyer Cheng Huan SC said the two men assaulted the defendant and inflicted injuries to his face and neck. Mr Cheng argued that Wong went into the female toilets by mistake. He tried to apologise to the woman but she misinterpreted his intentions, he said. The trial will continue before magistrate Peter Law on October 6.