Gao Zhisheng , a former coal miner, soldier, self-trained lawyer, Christian and ex-party member, was once recognised by the Ministry of Justice as one of the mainland's top 10 lawyers for his pro bono work. However, he ran afoul of authorities in 2004 after investigating the persecution of the Falun Gong, a spiritual group banned by the central government, and underground Christians. Since then, he's suffered six years of harassment, abuse, illegal detentions, beatings and torture at the hands of the government, which seems at a loss about how to deal with the man known to some as "the conscience of China".

Gao is among a handful of activists and dissidents whose arrest or disappearance make news around the world. Last month in Washington, US officials led by assistant secretary of state Michael Posner met a Chinese delegation for a formal dialogue about human rights. Posner said little afterwards about individual cases raised during the talks, except to note that the US side brought up Gao's case.

He was sentenced to prison in 2006 for "inciting subversion" after writing a series of open letters to President Hu Jintao and Premier Wen Jiabao , accusing the government of persecuting and torturing Falun Gong practitioners and Christians. Gao's licence to practise law was revoked and his law firm was shut down. He was given a suspended sentence in December that same year, after which things grew worse for the whole family. They were placed under constant surveillance, their movements were restricted and they suffered repeated abuse. For a period, police even moved into their apartment.

After sending an open letter to the US Congress in 2007, Gao was again detained and said he suffered more than 50 days of torture before being sent back home. Early last year, his wife and children were secretly smuggled out of China, eventually taking asylum in the United States. Shortly after, Gao "disappeared" again when he was taken from his family home in Shanxi by government security agents, who put a hood over his head. He did not resurface until late March this year, when he turned up at a Buddhist monastery town. He returned to his Beijing home on April 6 after 14 months in illegal secret detention. The South China Morning Post (SEHK: 0583, announcements, news) met Gao in his apartment two days after he returned home. But, his freedom was brief. Within a little more than one week, he had vanished again.

During the more than two-hour conversation, he repeatedly emphasised that it was not an interview, but a discussion among friends. He said he'd been warned that he would "disappear" again if he talked to the media, although he was sure the conversation was being recorded. His supporters believed Gao had been encouraged to speak with foreign reporters to get the word out that he had not been mistreated. Several days after returning home, Gao was taken away under a police escort to visit his father-in-law in Urumqi , in Xinjiang . His father-in-law called friends in Beijing to report that Gao would return to the capital on April 20.

He never arrived. His family has not heard from him since and the government has provided no details about what happened to him, leading to concerns that he has been detained once again and mistreated. Human rights experts believe the government introduced Gao to the public briefly to reduce the growing international pressure on his behalf, and took him away once they thought the pressure had receded.

At the time, Gao asked that details of the conversation not be reported because it might land him in more trouble. His friends, fellow lawyers and human rights workers now agree that his continued detention makes it unlikely that reporting his remarks will adversely affect him.

Gao seemed in good health and mentally fit, but was worried about his family, which has paid a heavy price for his activism. He said the most difficult choice for him was whether to abandon his activism so he would be allowed contact with his relatives.

"My freedom now has come at the cost of engaging in some lies. This is something that has really put a lot of pressure on me mentally and my sense of morality. If it were not for my family, I could not do this."

He seemed especially concerned about his older brother, who he said was like a father to him after their own father passed away when he was 12. He said his brother had developed stomach problems because he was worried about him.

"Each time I disappear, my bother can't eat," he said, adding his brother was suffering psychologically. "I feel terrible. My brother begged me, crying like a child, to stop the activism and allow the family to have a sense of peace. It's not difficult for me to be locked up in secret, but it's terrible for my family. I don't want to say much more. I hope this time, my resumption of contact with my family will be a bit longer."

Gao said he was very close to his father-in-law, who lives in Urumqi. After it was reported earlier this year that Gao was missing and might be in Urumqi, his father-in-law posted 600 notices with his photograph around the city to try to find him. However, someone followed closely behind, tearing each poster down as soon as it was put up.

He described how his father-in-law, with whom he had brief contact during his time in captivity, had also visited mortuaries every day looking at bodies, once mistakenly identifying one as Gao's "I have finally found you," the father-in-law said, bowing in front of the body before realising he had made a mistake.

Gao spoke movingly about his concern for his wife and two children in the United States. He sat on a chair in his spartan living room, the walls behind him covered with crayon drawings done by his young son, Tianyu - one of the few remaining signs of the family that once lived here. He told a friend that on his first night home he'd put his son's shoes beside his bed so that he would not feel lonely.

Gao's wife Geng He , daughter Gege , 16, and Tianyu, six, escaped to Thailand last year, and then were granted asylum in the United States. Gao said he had hoped they would forget him and everything that had happened in the past in China, but this was not the case. "The distance has made their concern for me increase." Gao said that his wife was struggling to take care of the family. His daughter was admitted to a hospital in December due to the psychological pressure, and his son appeared depressed.

"In the absence of their father, my children's psychological growth is suffering. Tianyu used to be a very feisty boy. Now he's extremely shy. Gege is worried about him. She said he can recall the names of 20 schoolmates from Yayuncun," he said, referring to a district of Beijing where they lived, "and asks his mother to let him call them. In Beijing, he would immediately disappear when he went downstairs. Now he basically clings to Geng He. These are not the conditions for someone to grow up in a healthy way.

"It's extremely difficult for my wife to manage, to do all this," he said. "I'm very worried. I spent a lot of time on the phone keeping her spirits up. For myself, I can take any kind of hardship, but I can't take knowing they're in trouble," he said. "It's like the situation of a moth flying into a candle and dying. They left China thinking it would improve their situation."

As his family struggles in his absence, Gao continues to endure his own nightmare at the government's hands. He provided details of his time in captivity, focusing on the irony of the fact that he could not have the "luxury" of actually going to jail.

"I'm a bit special among China's 1.3 billion people," he said. "I can't enjoy the privilege of being in prison in China. I can only have the option of disappearing. I often said to the people who detained me that the relationship between us was a legal one and that they should identify themselves as the government and treat me according to the law, and not just use mafia methods. They replied, `If you want to go to jail, you're just dreaming. Prison has proved ineffective in dealing with you'.

"My family in Shanxi said that if I were under house arrest or legally arrested and sent to prison they could accept it, because they would know that I'm alive."

Gao described the torture he received during a detention in 2007 as "like a dream to me". Last year, he was tortured for 48 hours, he said. In a personal account of his ordeal published in September 2007, titled Dark Night, Dark Hood, and Kidnapping by Dark Mafia, Gao described horrible beatings, electric shocks to his genitals, toothpicks being stuck into his penis and having lit cigarettes held up to his eyes for extended periods, causing temporary blindness.

"I can't associate what happened to me with the faces of Wen Jiabao and Hu Jintao. I can't believe they would have taken the responsibility for this or would have done this. But that's the reality of China today. Each time, I sort of turned off. I became very calm ... I would take food when fed and go to sleep when told to.

"They didn't let me watch TV, read any books or newspapers," he said. "During this period, I was like an animal. You're treated like an animal and the only way to bear this is to act like an animal," he said, adding that God had given him the courage to be able to bear the treatment. "You're required to sit in a fixed position for 16 hours a day. Sometimes facing the wall. If you move, someone will hit you on the head.

"Every three months they changed my location. When taken to another place, they would tie me up and cover my head with something. They forced me to bend when I walked. They treated me like the worst kind of terrorist."

He said that permission for even basic grooming had to go way up the political ladder. For 18 days after first being detained last year in Beijing, he was not allowed to shower or brush his teeth.

"I kept protesting and demanded to be allowed to brush my teeth and bathe. On the 18th day, a guy dressed in a Western suit came and told me: `We're paying great attention to the question of your bathing'. His answer was that the local authorities - the Beijing police - did not have the authority to approve this. He asked me to be patient. In Xinjiang they didn't give me toilet paper when I went to the toilet. They said, `You're an animal and don't need toilet paper. You're a beast and not a person, so you don't need toilet paper'. I went on a hunger strike for four days.

"My hair grew to my shoulders and they said they could not give me a haircut because I would have to wait for a response from the central government. They never said what level. The Beijing police and the Bureau of Public Security is very far from the level of approving a haircut, so my haircut was a big matter. They just shaved my head. I could only wash my hair once every 20 days."

He said he did not see the sun for 5  1/2 months, and when he asked his captors about it, the answer was: "We have been seeking instructions from above on whether you can go out. It's difficult to arrange." He asked if they could take the panel off the window, so that he could just hold his back to the window to get a little sunlight. They replied it was too difficult. "It seems they didn't even have the authority of letting me have sunlight."

Gao then turned quite serious for the first and only time in the conversation, saying the police had threatened to secretly exile him to a third country. This was the first time he showed any fear. "I was given to understand that it was possible that once I had settled in and the media interest had quieted down, that I might be forced to leave China. As long as I'm here, even if I do nothing, I'm still a problem for them."

He said he had not seen any newspapers in the more than a year he was in detention, until he bought the Southern Weekend, one of the mainland's most hard-hitting newspapers, his first day home. What he read made clear to him the party's control had increased and the political situation had worsened.

"The absolute exercise of power is much worse today than at any time in Chinese history," he said. "I looked at the newspaper yesterday ... so many things go against my conscience. I feel bad. I have to think about what to do. I have only been free for about 28 hours and I'm very conflicted. I was planning to calm down, but it's very difficult in this kind of situation."

He told an ancient story about some common people who retreated to the mountains to escape an evil government. A scholar asked them why they had fled to the mountains, where tigers could attack them at any moment. They replied: "The officials are far worse than the tigers. A government without restrictions is far worse than being exposed to tigers."

Gao then said he had few opportunities to see or talk to people and that he wanted to explain something that was very important to understand.

"I want to emphasise that if China cannot have democracy and constitutionalism, this will be a problem not just for the Chinese themselves, but the entire world," he said. "People outside China have to understand that what happens in China and the political situation here directly impacts the situation elsewhere.

"I want to thank the American government and all Western people who have been concerned, and continue to show their concern, because they are our only hope," he said. "The support of the foreign media, governments and people has given us confidence and courage and made it easier for us to bear the solitude of our activism," he said.

Gao said he was confident change would come. "There is one thing that I've never doubted, and that's that China will eventually have democracy and constitutionalism," he said. "Our only concern is when they will arrive.