Thousands of protesters demanding an investigation into the death of Tiananmen dissident Li Wangyang marched on the central government's liaison office yesterday. The demonstration took place as authorities in the activist's home city gave the first official account of how he died, saying his body was cremated 'at the request of relatives'. And in a major U-turn, a National People's Congress delegate from the city's leading pro-Beijing party said he would be writing to NPC chairman Wu Bangguo to express the city's concerns about the case. Ip Kwok-him, of the Democratic Alliance for the Betterment and Progress of Hong Kong, who previously said he would decline from writing to the NPC on the matter, said: 'We want to make public the facts.' A coalition of 30 local political and pressure groups organised the rally yesterday, which set off from Chater Road in Central at 3.30pm. The first demonstrators arrived at the liaison office in Western two hours later. Organisers said 25,000 people took part, while police put the figure at 5,400. Organiser Shum Wai-nam urged chief executive-elect Leung Chun-ying and local NPC delegates to 'express Hongkongers' anger' over the cremation of Li's body. He said: '[We] demand that the central government thoroughly investigate [his death].' The statement issued by the propaganda office of Shaoyang , Hunan province, emphasised Li died 'an accidental death' and the cremation was carried out 'at the request of relatives'. According to reports, Li's family did not consent to an autopsy or his cremation. The statement also said his funeral was held on Saturday with his sister and other relatives and friends present. It fell short of describing Li's death as 'suicide', the word used by Shaoyang's Daxiang Hospital, where Li, 62, was found dead on Wednesday. It said Li was found by staff hanging near a window with a white bandage around his neck. It also quoted Li's roommate as saying he had been 'acting weird' at about 3am. The statement said four forensic scientists carried out a 'completely videotaped' autopsy on Friday and the cause of death would be given when the results were obtained. By late last night, the statement had still not been carried by any official mainland media. Yin Zhengan, a friend of Li's, said Li's sister and sister-in-law were missing after being taken away by police. He added: 'I'd like to express my gratitude and admiration for the support from Hong Kong people.' Shaoyang activist Ouyang Jinghua said: 'From now on, anyone who dares to oppose the government may end up dying, just like Li. We know that's exactly what authorities want to achieve - muzzling dissent by stoking fears. But it won't work because we cannot be fooled by lies and we will not be intimidated.' Chief executive-elect Leung said: 'I believe the central government would be aware of Hongkongers' views on the issue.'