Authorities in China have detained the anonymous author of the Program-Think politics blog, who evaded government surveillance for around 12 years, subjecting him to brutal interrogations in a bid to gain a "confession," RFA has learned.

"Program-Think's family is asking for help," a comment posted to his blog dated May 24 said.

"Last week, he went on a business trip to a big city in East China, and lost contact with us the next day," the comment said. "There were no unusual messages before he lost contact."

"It has been almost a week now. At first, I was not sure if something happened, or if there was an accident, I didn't call the police," the comment said.

"Last night, the police gave us an official response [to our missing persons report], saying that they were processing his case, but ... without giving any information on the progress of their investigation," it said.

Twitter account @GFWfrog cited a source inside the state security police on June 14 as saying that Program-Think was detained by Shanghai police in early May, and that his last post on May 9 had been a scheduled posting.

"He is currently undergoing brutal interrogations to ensure a conviction," the account tweeted, adding that the case would be "a gift to the CCP on its centenary."

A person familiar with the matter who gave only his surname, Xu, told RFA that the anonymous blogger was now in police custody.

"Recently, through my own credible sources, I learned that they have detained Program-Think, and are putting him through harsh interrogation," Xu said.

"I can't accept the persecution of a person of such conscience and outstanding ability ... so I have to make this information public despite the risks," he said.

Exposing hidden wealth

Xu said Program-Think was likely detained for exposing the hidden wealth of high-ranking members of the ruling Chinese Communist Party (CCP), and his political theorizing and anti-brainwashing campaigns, conducted via his blog on the overseas-based Blogger.com platform.

Xu said he had himself been transformed from an uncritical supporter of the CCP to a person with doubts, and then to someone who longs for freedom and democracy, after reading Program-Think's blog.

The blogger had continued an in-depth analysis of CCP leaders' wealth following the publication of the Panama Papers in 2016, Xu said.

"I think Program-Think had a bigger impact than anyone on the Chinese internet," Xu said. "Particularly his posts laying out very complete evidence to refute [government] propaganda."

"He would convert Little Pinks [CCP supporters]. He is a hero, and totally irreplaceable," Xu said.

A legendary figure

Zhou Fengsuo, of the U.S.-based NGO Humanitarian China, agreed.

"Program-Think is a legendary figure; an anonymous Chinese rebel," Zhou told RFA. "He had advanced anti-censorship technology."

"A lot of people learned how to circumvent the Great Firewall [of government censorship] through his blog," he said. "He posed a huge threat to the CCP's totalitarian rule."

"I am very worried about him, as we haven't heard from him in a very long time, and it is very likely that he has been detained," Zhou said.

Repeated attempts to contact Program-Think's family members were unsuccessful.

Program-Think was nominated for best Chinese blog in the 2013 Deutsche Welle International Best of Blogs awards, or BOBs.

The author told the station at the time that he had never set out to write political content to begin with, but just wanted to share his years of experience in programming.

But the blog gradually become popular with people wanting ways to get around government censorship, and later branched out into information security tips and political analysis, the station reported at the time of the blog's nomination.