A Beijing law firm says it is unaware of the whereabouts of one of its top public interest lawyers, amid a nationwide clampdown sparked by government fears of a "Jasmine" uprising inspired by recent events in the Middle East.
Jin Guanghong, who has represented members of the banned Falun Gong spiritual movement, was incommunicado on Tuesday, his firm said.
"I don't know his situation now," said an employee at the Beijing Jingfa Law Firm. "I couldn't get hold of him at the time, but I just thought that was because he was in court."
"All the lawyers have to turn off their cell phones when they are in court."
Jin's last known communication with the outside world was on Friday. Repeated calls to his cell phone number on Tuesday resulted in a recorded message saying the phone was switched off.
The attorney had defended a member of the banned Falun Gong spiritual movement in the Luoyang district of Guangzhou.
He was also on the legal team for a group of three Fujian bloggers jailed on defamation charges after they reported doubts about the official version of events surrounding the death of a young woman.
Beijing-based rights lawyer Lan Zhixue said he was surprised at Jin's "disappearance."
Lan described Jin as an erudite legal scholar and a lawyer of high principle.
"He is a highly respectable lawyer, very moderate and steady," Lan said. "He isn't remotely showy, not at all."
"It's very strange. Why would this have happened to him?"
Lan said he was concerned for Jin's safety. "If he has just been 'disappeared' for no obvious reason, then I think that he could be in great danger."
The fears for Jin's safety come amid a worsening climate for public interest and civil rights lawyers in China.
Others go silent
Since a group of anonymous young Chinese posted calls for "Jasmine" rallies to protest against corruption and call for political change eight weeks ago, the authorities have swooped down on large numbers of individuals listed on a nationwide "stability protection" database.
Recently, top civil rights lawyers Jiang Tianyong and Teng Biao have also stopped communicating with the outside world, with a third, Tang Jitian, being held under house arrest.
Guangzhou-based Tang Jingling is also missing, believed detained.
China's national security police frequently use "soft" detention tactics around sensitive anniversaries and politically charged times.
They may escort dissidents and activists out of town to holiday resorts, where they are kept under constant surveillance, or order them to remain at home and contact no one, with a police guard on their door.
However, top human rights lawyer Gao Zhisheng, who reported being extensively tortured during detention, disappeared in April 2010 and hasn't been heard of since, despite widespread calls for his release and fears for his safety.
Taiwan-based lawyer Zhu Wanqi, who follows developments among her colleagues in mainland China closely, said the authorities have become increasingly jittery in the wake of recent popular unrest in the Middle East.
"One after another, these things are blowing up against dictatorial regimes," she said. "Of course the Chinese Communist Party can't tolerate it."
"Of course they are going to start looking to their own political power, and keep things going along with their 'stability and harmony.'"
"Now you can't say anything on the microblogs any more," Zhu said. "If you do, it just gets deleted immediately."
"They are never going to let up."
Jin, who also signed Charter 08, a controversial document calling for widespread political change, last sent an update via the popular microblogging service Twitter on April 5.
Charter 08 co-author and 2010 Nobel peace prize winner Liu Xiaobo was jailed as soon as the charter was published, and was later sentenced to an 11-year jail term for subversion in December 2009.
Reported by Qiao Long for RFA's Mandarin service. Translated and written in English by Luisetta Mudie.