SINGAPORE - The National University of Singapore (NUS) law professor involved in the sex-for-grades trial claimed that he was ordered to go to the Corrupt Practices Investigation Bureau (CPIB) on the day he was discharged from the hospital. 41-year-old Tey Tsun Hang, is facing six charges of obtaining sexual gratification from his former student Darinne Ko, in exchange for better grades. Tey was admitted to Alexandra Hospital from 2 April to 5 April last year. On 2 April 2012, he was picked by up by CPIB officers for investigation. Tey claimed that during the interrogation on 5 April last year, he was badgered by CPIB officer even though he was in a "very fragile condition".