POLICE are preparing for a triad war in Tsim Sha Tsui following the conviction of film producer To Luen-shun for being a member of the Sun Yee On triad. To was found guilty on Wednesday of triad membership and was remanded in custody by the District Court for two weeks pending sentencing. His conviction confirms the link between the triads and the film industry which has long been suspected but was difficult to prove. It also shows connections between the Sun Yee On and Thai boxing, as police believe it was To who was behind a Muay Thai Boxing Council tournament last year. But as the 28-year-old prepares to spend up to three years in prison, officers of the Organised Crime and Triad Bureau believe rival triad groups could move in on To's Tsim Sha Tsui turf. Although he was acquitted of two charges of being an office bearer of the Sun Yee On and assisting in its management, the police believe he was an influential figure in the Sun Yee On. They said his absence is likely to cause a power vacuum which could produce fierce infighting. ''It could be that other members of the Sun Yee On will try to take his place while he is in prison,'' a senior bureau source said. ''But other triad groups such as the 14K may see it as a chance to move in and take control.'' The Sun Yee On has a grip on Tsim Sha Tsui's lucrative nightclub area, taking millions of dollars each year in protection money. ''He [To] will never be able to claim to be just a legitimate businessman. His conviction will send a warning to other triad members who previously thought they were untouchable,'' the source said. Two original witnesses who were to have given evidence at the trial disappeared and are still missing. Police believe they were paid by the Sun Yee On to stay away. To, married with a small child, was arrested in January last year in a Wan Chai bar with Andely Chan Yiu-hing, the reputed Sun Yee On boss of Wan Chai who was murdered in Macau last year. Intelligence gathered by the bureau suggested that both Chan and To were destined to become the future leaders of a new generation of Sun Yee On. To's film business, Chun Yue Amusement Production Ltd, made one film last year starring actress Maggie Cheung and singer Jackie Cheung. But its address at 37 Hillwood Road, Tsim Sha Tsui, was the same address given by the applicant for the licence to stage a Muay Thai Boxing Council tournament at the Queen Elizabeth Stadium on December 28 last year. The Television and Entertainment Licensing Authority granted the licence despite knowledge that To was facing trial at the time, because the actual licensee was another man who had no previous convictions or known triad links. The Hong Kong Boxing Association has constantly maintained its distance from the Muay Thai Boxing Council. Peter Tsi Ka-kei, chief executive of the Motion Picture Industry Association in Hong Kong, said he felt the film industry was no different to any other regarding triad involvement. ''I would not say there is a dominant or controlling factor [of triads] in the industry,'' he said. ''This is just another case, the only difference being that everyone has their eyes on the film industry because it is glamorous.''