Concerns are growing over the health of a former leader of the 1989 student-led democracy movement, currently charged with subversion in the southwestern Chinese region of Guangxi.
Zhou Yongjun was charged by the state prosecutor in Guangxi's Dongxing city with "incitement to subvert state power" last December, paving the way for a trial.
He has been held in the Dongxing Detention Center for the past eight months, according to his lawyer Tan Yongpei.
"His case was recently transferred to the prosecutor's office," Tan said. "Mostly, bail isn't granted [in cases like this]."
Tan, who visited his client on Tuesday, said there are concerns over Zhou's health, as he suffers from a dermatological disorder.
"His main demand is that he receive medical treatment," he said.
A friend of Zhou's, who gave only his surname Nong, said Zhou's detention could be a way to prevent him from marking the 30th anniversary of the massacre of civilians in and around Tiananmen Square by People's Liberation Army (PLA) troops, starting on the night of June 3, 1989.
The ruling Chinese Communist Party has never changed its official verdict on the weeks-long student-led democracy movement, which it regards as a "counterrevolutionary rebellion."
Memorials forbidden
Public memorials and events marking the anniversary of the bloodshed are forbidden in mainland China, although Hong Kong still holds an annual vigil attended by thousands of people.
"According to our assessment, this is probably part of the security measures linked to the 30th anniversary of June 4," Nong told RFA. "He may get out on bail after June 4."
"We call for his immediate release ... [because] we are mostly concerned about his health," he said.
Former 1989 democracy activist Gao Jian, who is now based in Australia, said he knew about Zhou's case.
"The mainland authorities are stepping up the pressure on all dissidents, rights activists, and petitioners, to a much greater extent than before," Gao said.
"In the past, a lot of dissidents used to go back to China regularly, but now they daren't go back at all, because this year is different," he said. "They are being extra careful."
Zhou Yongjun was initially detained last August in Guangxi's Dongxing city, near the border with Vietnam. His case has been sent to state prosecutors in Fangchenggang city, which is administered by Dongxing.
Lawyers say "subversion" charges are a catch-all crime used to target peaceful critics of the ruling party.
Zhou has served a number of prison sentences ever since his initial involvement with the pro-democracy movement on Tiananmen Square, only being released from the last in 2015.
If his case goes to trial, he could face another jail term of up to 10 years.
A prominent figure
Zhou was a prominent figure on Tiananmen Square in 1989, and was photographed by international media kneeling on the steps of the Great Hall of the People in a plea for China’s communist leaders to heed student calls for political reforms.
He was arrested and jailed for two years in the subsequent crackdown on student protesters in June 1989, losing his university place and his Beijing "hukou," or residence permit.
Zhou fled to Hong Kong and then traveled to the United States in 1993, living in New York City and Los Angeles.
He was detained again in 2009 for using a false passport to visit his ageing relatives after the Chinese consulate refused to renew his passport and imprisoned him on a fraud charge. His lawyers said Zhou was tortured in detention and denied family visits.
Zhou had also tried to visit China once before in December 1998 but was arrested in Shenzhen and spent more than two years in a labor camp.
Reported by Wen Yuqing for RFA's Cantonese Service, and by Wu Jing for the Mandarin Service. Translated and edited by Luisetta Mudie.