Authorities in China have detained or questioned at least 500 people in the past year over online comments in support of exiled billionaire Guo Wengui, who is on Beijing's most-wanted list for a number of criminal charges, RFA has learned.
Guo, who also goes by the name Miles Kwok, had an Interpol "red notice" issued for his arrest in April 2017.
He has vowed to expose what he calls a small clique of corrupt "kleptocrats" in charge of the ruling Chinese Communist Party.
Beijing-based rights activist Zhang Baocheng said at least 500 people have been hauled in to "drink tea" with the state security police over their apparent support for Guo on social media since last year.
"I am absolutely certain that more than 500 people have been asked to 'drink tea' and so on, at the very least," Zhang told RFA on Tuesday.
"There are so many groups on WeChat where people have been called down to their local police station to give a statement just for being a member of a chat group [where something sensitive was posted]."
"They were also forced to withdraw from these groups ... some of which had several dozen members."
Zhang said the authorities regard any mention of Guo and his overseas threats to reveal Communist Party secrets as particularly problematic.
"Internet censorship is very tight now, particularly when it comes to Guo Wengui, and that includes WeChat groups," he said.
Not everyone gets off with just a bout of questioning and a warning, however.
Authorities in the northeastern province of Liaoning recently detained Zhao Qin, known by her online nickname Tian Ai, on suspicion of "picking quarrels and stirring up trouble" after she made comments about Guo's revelations to overseas media organizations.
And fellow social media user Shi Jinsheng, known by his online nickname Cangtian Youxian, is currently out on bail after being detained for writing about Guo online.
A source close to Zhao told RFA that she was detained in Liaoning's port city of Dalian on the morning of June 7 after given a foreign media interview.
"She gave an interview ... in which she expressed support for Guo Wengui, so they blocked off the door of her home by having a tipper truck dump a load of stones outside," the source said.
"When she went down to the police station to report it, they held her under criminal detention."
Zhao is well-known in the local rights community for championing the rights of vulnerable people and for campaigning against official corruption, the source said.
She frequently posted to WeChat and Twitter, hitting out at the current social system in China, and the dictatorial rule of late supreme leader Mao Zedong.
Meanwhile, Shi Jinsheng was released on a year's bail on June 15 after being detained on suspicion of "picking quarrels and stirring up trouble," the source said.
He frequently posted on WeChat in support of Guo, and supported his view that the Chinese leadership is largely a "kleptocracy."
"He will be under residential surveillance for a year," the source said. "They can just accuse you of spreading online rumors and detain you, without even any kind of formal notification," the source said.
"Then they wait to see if you set up more WeChat groups, or if you persist in your support for Guo Wengui."
Guo, who has applied for political asylum in the U.S., has warned that the threat to the U.S. from Chinese espionage is "100 or 1,000 times" greater than that posed by major terror attacks on U.S. soil.
The Associated Press has reported that Chinese prosecutors are investigating Guo "for at least 19 major criminal cases," which included allegedly bribing intelligence officials, kidnapping, fraud, and money laundering.
In August, the AP revealed that Chinese authorities have requested a second Interpol warrant for Guo, on a claim that he raped a 28-year-old former personal assistant.
Reported by Qiao Long for RFA's Mandarin Service. Translated and edited by Luisetta Mudie.