Gao Zhisheng is a self-taught lawyer who ran afoul of the Chinese government. On 4 February, witnesses say he was abducted by security personal and hasn't been seen since.
Gao has defended the most persecuted people in China, including people forcibly evicted by the government, practitioners of Falun Gong, and other minority groups. He wrote an open letter to the U.S. Congress detailing the level of repression in China.
Missing: Gao Zhisheng
Jerome Cohen, of New York University's School of Law, met Gao briefly in 2006. He was struck by Gao's stubborn determination to confront the Chinese system:
"I said to him, "if you continue to take that posture in public, I'm afraid a year from now, you're not going to be on the street and available to help people."
Cohen's warning was correct. After a suspended sentence for sedition in 2006, Gao was placed under effective house arrest. In 2007, he was abducted and tortured.
A recently released account of that arrest describes daily torture:
"After the 12th and 13th day of my kidnapping, and when I could again partially open my eyes, I saw my body was in a horrifying condition. Not a single square centimetre of my skin was normal. It was bruised and damaged over every part."
Rights campaigners fear that he could be experiencing the same treatment now.
Gao's current disappearance, Cohen suggests, may have something to do with the imminent visit of U.S. Secretary of State Hillary Clinton.
In the longer term, Sharon Hom of Human Rights in China is concerned that the harassment of rights defenders will increase as the 20th anniversary of the Tiananmen protests nears.
"This is a process where rights defenders are picked up, released, harassed, beaten, and released. This is part of a pattern, but it's an intensifying one."
Let history decide
Activists and the lawyers who defend them are always at risk of harassment or worse. So why do they do it?
Mo Shaoping is a defence lawyer in Beijing. He's been involved in dozens of what he calls ‘sensitive' cases, relating to human rights.
Some of these cases relate to freedom of speech, others are to the founding of democratic parties, and others involve the Tiananmen protests of 1989.
Mo endures harassment, following, and even surveillance by the authorities. But he is resolute in his work, explaining:
"I believe that everyone has rights, and everyone involved in a criminal case has the right to a lawyer to defend them. If no one defends these people, their rights to have a legal defence is taken away. I also believe in getting things onto the record. We have a saying in China, 'let history prove it'. So, eventually, history will prove who is right and who is wrong."