Close associates of Chinese legal activist Xu Zhiyong say he is being detained on charges of tax evasion. Xu's case is one of several that appear to be part of widening crackdown on dissent in China ahead of October's 60th anniversary of the founding of the People's Republic of China.
More than a week ago, without explanation, Chinese police detained Xu Zhiyong, the head of a legal aid organization Gongmeng in Beijing.
Teng Biao, a co-founder of the group, says Xu's family has not seen him since he was taken from his home early on Wednesday last week.
Teng says Xu's brother went to the Beijing University of Post and Telecommunications, where Xu Zhiyong taught. There, he learned that his brother had been taken away by public security forces and was being charged with tax evasion.
Teng added that Zhang Lu, another member of Gongmeng who also has been missing since last week, has still not been heard from.
Many political analysts and human rights groups say Gongmeng and other activist groups are being targeted as part of a widening crackdown on dissent ahead of the October 1 anniversary of the founding of the communist government.
However, Randy Peerenboom a professor of law at La Trobe University in Melbourne who is now based in Beijing, sees a broader purpose. He thinks what is happening is part of an effort to ensure social stability that is not exclusively linked to the coming anniversary.
"The number of demonstrations has been rising in recent years, many of them becoming more violent, and so you see the government trying to crackdown on various sources of instability," he said.
Peerenboom says the government has tried to force many of the country's disputes and controversial cases into the court system, but in his opinion that has ended up being too costly and has not ended the protests. Because of that, the government has started targeting activist lawyers and legal groups like Gongmeng.
"I think that one of the problems is they've [Gongmeng] handled an increasingly wide range of cases and gotten involved in a wider range of issues and this is one of the reasons why I think the government is re-calibrating its strategy," he said.
Gongmeng's lawyers represented victims of the Sanlu toxic milk powder scandal, which made nearly 300,000 babies ill, and has investigated institutions such as illegal detention centers. Their researchers even issued a review of last year's unrest in Tibet, which said Tibetans were protesting because of failed government policies.
Gongmeng is not the only one being targeted.
Last month, Yirenping, which fights discrimination against hepatitis patients, faced a clampdown, and more than 50 Beijing lawyers, many of whom focus on human rights issues, had their licenses revoked.
Two activists who have criticized the government's handling of the 2008 Sichuan earthquake have also been put on trial.
One of them, Huang Qi, appeared in court Wednesday ON charges of illegally possessing state secrets.
Tan Zuoren, an activist who questioned why so many children died in the earthquake, will be tried for subversion next week.