A FILM company shareholder was injured when she opened a letter bomb at her Quarry Bay office yesterday. An employee of Mandarin Films Singapore Pte Ltd was also taken to hospital suffering from smoke inhalation. The Organised Crime and Triad Bureau (OCTB) has taken over the investigation of the incident to see whether it is connected with triad activity in the film industry. Siu Fook-ping, 43, received burns to her hands when she opened a large envelope yesterday morning in her 18th floor office in the Westlands Centre, Westlands Road. Ms Siu and employee Lee Koon-fun, 21, were taken to Lady Edward Youde Hospital, where Ms Lee was treated and discharged and Ms Siu was admitted in a satisfactory condition. Ms Siu was questioned by five OCTB officers yesterday afternoon at the hospital. She was discharged at about 7 pm with her hands in bandages. Two friends accompanying her said her condition was ''not bad''. Film-maker Raymond Wong Pak-ming, one of the company's owners, visited Ms Siu at about noon. A special OCTB taskforce was set up to investigate links between triads and the entertainment industry after the gangland murder of Sun Yee On triad boss Andely Chan Yiu-hing in Macau last year. Chan had links with several film producers, actors and actresses. OCTB senior staff officer Detective Senior Superintendent Peter Yam Tat-wing said: ''We were told by explosive ordnance disposal officers that the device was not lethal. It contained four small batteries, a switch and a small container with an inflammable substance.'' Bomb disposal officer Dominic Brittain said the incendiary device was a classic letter bomb. ''It was designed to burn rather than explode. It was made up in the usual way.'' he said. Mandarin Films moved into the 400-square metre premises last month from offices in Wan Chai and Central. Two years ago, five men armed with pistols and knives went into the company's processing laboratory and stole two reels of director Ko Chi-sum's film All's Well Ends Well. It is believed the raid was provoked because a film producer could not persuade a contract actor from a rival company to work for him. Mr Wong was last month engaged in a business dispute in Macau with another movie maker, who had earlier been interviewed by Macau police because of his links to Andely Chan.