An eight-week crackdown by the authorities across China is beginning to take its toll on political and civil rights activists, who say many of their fellow activists have succumbed to intense political and personal pressure.
"The local national security police brought me home last night," said outspoken blogger Guo Weidong.
"I have promised, so please don't ask me anything about the case," Guo, who is known online by his nickname "Daxa," said.
"I'm not allowed to give interviews."
Guo was taken from his home in the eastern province of Zhejiang by police from his home district of Haining on March 10, for investigation on charges of subversion.
Police also searched the couple's home and Guo's office, taking with them Guo's computer and a DVD documentary about prominent artist and social critic Ai Weiwei and some Hong Kong periodicals.
Ai was also detained earlier this month, sparking an international outcry and an online campaign for his release. China has denied his detention has anything to do with human rights or freedom of speech, however, saying that Ai is under investigation for "economic crimes."
Ai's family said on Monday they had still had no formal word of his whereabouts or legal status.
"We tried to inquire directly with the municipal police department but they wouldn't accept our inquiry," said Gao Ge, Ai's sister-in-law.
"They said we would have to go through the district where [he] is registered."
She said the family continues to maintain Ai's innocence. "These slanderous accusations are because they can't find anything else on him," she said. "Ai Weiwei really is innocent."
Many of those detained since the online call for a "Jasmine revolution" was published by a group of young, overseas Chinese had taken no part in the "Jasmine" rallies, which have drawn heavy security and media interest but were sparsely attended in major cities.
Nonetheless, activists said the government was rattled by the comparison with Middle Eastern uprisings in Egypt and Tunisia, and launched a preemptive strike on activists around the country.
Chinese online activists have reported a flurry of pro-government activity via social media and microblogging sites since the "Jasmine" crackdown began.
"They are sending out fake tweets," said a Fujian-based netizen surnamed You. "The accounts look a lot like [the originals]."
"For example, they might add a '1' to the front of the account name, or turn a zero into an 'O'."
"There is one Ai Weiwei account that substitutes 1 for 'I'," You said.
"They will be on there saying rude things for a long time, and then you realize they are being rude about the person they are impersonating," he said.
Ai Xiaoming, a literature professor at Guangzhou's Zhongshan University and frequent Twitter user, wrote via a microblog update on Saturday that she had seen a number of accounts created that mimicked her account, and then sent out extremist tweets.
A microblogger who requested anonymity said he thought the microblog account imitators were agents provocateurs.
"It seems to me that they are trying to incite people into committing a crime, a bit like Wang Yi," he said, referring to a Nanjing-based activist who was recently sentenced to a year in labor camp over a single anti-Japanese tweet.
Xiamen-based blogger and online activist Peter Guo said the campaign by the impersonators, sometimes referred to as the "Fifty Cent Army" because they are paid a small amount of money per pro-government posting, had led to divisions and recriminations within the microblogging community.
"The online atmosphere has really deteriorated, I feel," Peter Guo said. "There are a lot of suspicions and accusations being traded back and forth."
"It's impossible to reestablish mutual trust now ... There are people attacking each other, exposing each other, informing on each other," he said.
Peter Guo said the widespread crackdown by the authorities on online activists and dissidents had taken its toll on many netizens.
"I'm not afraid that the government will take control of our microblog accounts," Peter Guo said. "I am more afraid that these [online activists] have been forced into changing their standpoint."
"Perhaps they are having pressure put on them via their family or their employer," he said. "They are suddenly starting to speak up on behalf of the government."
"This phenomenon is quite disturbing; nonetheless I still respect their views," Peter Guo said.
Hong Kong veteran democratic politician and trade-unionist Lee Cheuk-yan said there is currently a "white terror" sweeping China.
"Any dissident voices are being oppressed, silenced, and taken away," Lee said during a protest calling for Ai's release at the weekend.
"There is an atmosphere of white terror across China now," he said. "This use of economic crimes [against Ai] really is a last resort on the part of the Chinese Communist Party."
China on Saturday hit out at a recent State Department report detailing human rights abuses, calling it a pretext for interference in Beijing's internal affairs.
"We are firmly against interfering in our internal affairs under the pretext of human rights issues," foreign ministry spokesman Hong Lei said in a statement.
Hong said all ethnic groups in China enjoy "extensive freedom and rights."
Reported by Qiao Long and Ding Xiao for RFA's Mandarin service, and by Grace Kei Lai-see and Dai Weisen for the Cantonese service. Translated and written in English by Luisetta Mudie.