Hospital staff said the room was locked soon after police concluded their investigations and removed Li's body within a few hours of his death.

'We don't know why it is still locked and our hospital has nothing to do with it,' one doctor on the seventh floor said on Monday.

None of patients on the floor, most of whom were admitted in the past week, said they knew anything about Li or his death last week.

The early government explanation of Li's death, which said he had taken his own life just two days after this year's 23rd anniversary of the crackdown, has been widely challenged.

Members of Li's family, friends and fellow activists suspect foul play.

People who saw his body said Li was found dead near the window with a noose of white bandages around his neck. The noose was tied to the window frame.

Pictures, taken at the scene by one of Li's friends shortly before his body was taken away by police and posted on the internet, show Li's feet on the ground and clothed in slippers.

Many friends who visited him in hospital over the past year said the ailing June 4 activist, who was famous for his dogged perseverance after serving two jail terms totalling 21 years, had neither the motivation nor the physical strength to commit suicide.

Although he could barely walk and had become blind and deaf after years of torture in jail, Li was recovering from serious illness, including heart disease and diabetes, but remained hopeful, his friends told the South China Morning Post.

Supporters also asked how Li, under close guard by up to nine state security officers in the lead-up to the sensitive June 4 anniversary, could have been allowed to hang himself in the first place, and why hospital authorities appeared to have made no attempt to rescue him.

The local government's handling of Li's death, especially the hasty cremation of his body despite widespread opposition and a crackdown on local activists that was launched a few days before his death, has fuelled public suspicions.

Echoing an appeal by dozens of mainland activists for an open inquiry into Li's death, thousands of people in Hong Kong marched on the central government's liaison office on Sunday to protest against the mainland authorities' treatment of Li and other democracy activists.

An online petition calling for a probe by higher-level authorities, initiated by several mainland activists outside Hunan, has registered more than 10,000 signatures.

In an interview at the hospital on Monday, Lu Haiping , a deputy propaganda chief of the Daxiang district, shrugged off talk of foul play and reiterated the conclusion of the first official statement issued by his office the previous day, which described Li's death as 'an accident'.

'Everything we said in the statement was based on the truth that we have obtained from police investigations so far,' he said.

Veteran activist Ouyang Jinghua , 72, a signatory to Charter 08 - the 2008 manifesto drafted by activists which calls for basic democratic and human rights - travelled more than 200 kilometres from Suining county in the Shaoyang suburbs to meet Li on June 4. He said that although Li was in poor health, he was in a fighting mood and showed no signs of wanting to die.

'When I sneaked into Li's ward, only he and his sister were there and he was glad that I managed to visit him on the anniversary,' Ouyang said. 'We chatted briefly about a recent health check-up he had ... which showed minor signs of cerebral infraction. He was optimistic and promised to seek treatment.'

He said security was particularly tight in and around the hospital on that day. 'When I left, I was intercepted on the seventh floor by at least three security officers and taken away to a nearby police station for further interrogation,' he said.

Later, Ouyang was told by state security officers from his own county that he risked repercussions if he continued to get involved in calls for an inquest into Li's death.

'They told me that I could travel anywhere I want to across the country - except Shaoyang city,' he said.

Zhang Shanguang , from nearby Huaihua , who was jailed for nearly 17 years in the same prison as Li, said in an interview shortly before he was taken away by local police on Saturday that he could never believe that a 'tough guy' like Li would ever choose to kill himself.

'I was so shocked to learn that Li died in an alleged suicide attempt,' Zhang said. 'You won't believe that, just like me, if you know what he has been through all these years.'

Zhang and other activists said Li was almost tortured to death over his resistance to demands that he confess during his first 11 years in jail -which began shortly after the June 1989 crackdown - because of his involvement in the student-led demonstrations.

When Li was released in 2000, two years early, on medical grounds, he had lost his sight and hearing and many of his teeth, and he was nine centimetres shorter.

He was thrown back in jail for another decade after staging a 22-day hunger strike demanding government restitution and medical treatment and for his involvement in the banned China Democracy Party.

His younger sister, Wangling, was also sentenced to three years of 're-education through labour' for helping him disseminate his message.

Another activist, Huang Lihong, a middle school teacher in Longhui county, Shaoyang, said she had met Li on more than a dozen occasions over the past year and Li had talked about staging another hunger strike to fight against unfair government treatment . 'He said it was not because he wanted to die. He said he would rather have died in the Tiananmen crackdown and would fight until his last breath,' she said in a telephone interview before being taken away by the authorities late on Monday night.

Huang said she and many activists in Shaoyang had never heard of Li until he was released from jail last year. 'Li Wangyang may not be as famous as many other rights activists due to his long time in jail, but he was a true hero as well as an inspirational figure for all of us who ... pursue democracy and freedom,' she said.

Huang said Li regretted that his sister and her husband had also paid a dear price for his steadfastness and that his friends were constantly harassed for supporting him.

'He was in pain both physically and psychologically, but he had never given up hope and always encouraged us to persevere because we may be witnessing the darkest moment before the dawn,' she said.

Fellow activist Zhu Chengzhi , who went to junior middle school with Li, said Li had asked Wangling, who had taken care of him since his release last year, to buy him a radio on June 5, in an apparent attempt to help restore his hearing.

Zhu met Li for the last time on June 4 and told the South China Morning Post on the day Li died: 'I simply don't think it was a suicide because Li was the kind of guy who would never commit suicide even if a knife was held against his neck.'

Zhu, who went missing a day later, has been ordered to be detained for 10 days due to his outspokenness, the US-based group Human Rights in China said, citing Zhu's wife.

Li's friends said it had become extremely difficult to communicate with him. 'It was quite an effort to talk with him and we had to write on his hands or on his thighs what we wanted to say, one character at a time,' said one young activist based in Changsha .

'Li would pronounce the character, and if it was correct, we patted his hand once or twice and then went on writing the next character,' he said. 'If it was wrong, we drew a line and had to write it again. But he was eloquent and often in high spirits.'

Yin Zhengan, a close friend of Li who was also at the hospital on the morning of June 6, said it would be extremely difficult to find sufficient evidence to challenge the official findings. 'With the cremation, I think it is almost impossible to find out the truth,' said Yin. 'I cannot think of any motive for Li to hang himself because he was such a persistent and optimistic guy.'

Beijing-based lawyer Tang Jitian said the authorities in Shaoyang had failed to produce a credible explanation of Li's death or eliminate public doubts that the case had been handled properly.

'Their attempts to stifle dissent and organised opposition by restricting citizens' freedom are obviously at odds with existing laws and regulations,' he said. 'Such practices underline the deep-rooted sense of insecurity among the authorities, which usually results in overreaction and arbitrary measures and only exacerbates lawlessness.'

21

The number of years Li Wangyang spent in prison, the longest of any of the 1989 pro-democracy activists.