FOUR Correctional Services Department (CSD) officers yesterday denied charges in connection with the death of a 20-year-old detention centre inmate. Sin Kong-meng was unlawfully killed at Sha Tsui Detention Centre, Lantau, on August 13, 1991, according to an inquest in March last year. Chan Sai-cheong, 31, Wong Sze-yuen, 29, Yan Hung-tik, 30, and Kwok Man-yau, 31, were suspended from duty this April. Chan is charged with assaulting Sin, causing him actual bodily harm. Wong is accused of attempting to pervert the course of justice. He allegedly told an inmate, Lee Kwok-wai, that if the police asked him whether CSD officers had assaulted Sin he should answer ''no''. Yan faces four counts of common assault. Two of the charges allege that he assaulted Sin. It is also alleged that he assaulted Lee in April 1991 and Wong Yan-kit in July 1991. Kwok faces one charge of common assault on Sin. He also faces a count of attempting to pervert the course of justice. They have all denied the charges. District Court Deputy Judge O'Donnell ordered the case to be set down for an eight-day trial beginning on February 8 next year. He extended bail on the officers' own recognisance.