Wang Bingzhang, sentenced to life in prison in China for "spying and terrorism", has been fearlessly challenging the Chinese authorities for 20 years.
Wang Bingzhang has lived overseas since 1979
From his place of exile in the United States he founded two political groups which are banned in China and a pro-democracy magazine, China Spring.
At the age of 55, he is considered one of China's veteran dissidents.
His four children are all US citizens, but Mr Wang has refused to take citizenship himself, arguing that it is easier to fight for democracy in China as a Chinese citizen, his associates have said.
Mr Wang began speaking out against the Chinese political system at the start of the Cultural Revolution, and was jailed in 1966 and 1967.
He was sent to Canada to study medicine in the late 1970s and then moved to the United States after obtaining his degree.
From his new home in New York, he founded the magazine China Spring and the China Alliance for Democracy, an exiled dissident group.
Smuggled copies of China Spring circulated widely in China during the 1980s.
'Vowed to return'
But it was his high-profile return to China in 1998 that was considered one the boldest challenges to the Chinese authorities.
He went there to organise the opposition Chinese Democracy and Justice Party, to press for free elections and civil liberties.
But he was caught and expelled after only three weeks.
The Chinese Government has blacklisted scores of political dissidents whom it refuses to allow into the country, even if they possess Chinese passports.
Wang called me and told me there was a possibility that he would try to enter China
Fellow activist Fang Yuan
Mr Wang was apparently not deterred by the experience.
He vowed to return to China to battle for the right of dissidents to go back, human rights groups said.
It appears that he may have tried to sneak into China again earlier this year, before his arrest was confirmed by Chinese authorities on 5 December.
A fellow activist, Fang Yuan, said Mr Wang phoned him from Vietnam, where he was travelling, on 26 June.
"Wang called me and told me there was a possibility that he would try to enter China," he said.