Voice of America was in the middle of a telephone interview with dissident professor Wenguang Sun on Wednesday night when Chinese police burst into his house and dragged him away. His last words were, “I am entitled to express my opinion. This is my freedom of speech!”

Sadly these assertions by the professor proved to be inaccurate, as the tyrants of Beijing made him disappear. Efforts by VOA’s Issues & Opinions television show to get back in touch with its kidnapped guest have been futile. According to VOA:

VOA Mandarin has attempted to reach professor Wenguang Sun by cellphone and WeChat, a popular social media platform, since he was removed from his home during the Wednesday night broadcast. The professor, who lives in Jinan, the capital of eastern China’s Shandong province, has not responded. Sources in Shandong told VOA he was under house arrest.

Yibing Feng, VOA’s correspondent in Beijing, called the Information Department of the Ministry of Foreign Affairs of China for comment, but the mobile phone open to the public was turned off, and the landline was not answered. Feng also contacted the Public Security Department of Shandong University and the Shanda Road Police Station of Jinan’s Public Security Bureau. Neither would comment.

Professor Sun is a noted human rights activist who appeared on Issues & Opinions to discuss what he calls the “throw-money diplomacy” of Beijing. He recently wrote an open letter to Chinese President Xi Jinping criticizing Xi for spending too much money on foreign loans and investments instead of improving the lives of Chinese citizens. Xi received the letter just as he was setting off on a trip to Africa to do exactly what Sun criticized him for.

The letter was widely interpreted as a critique of China’s “Belt and Road” international infrastructure program, which is actually much more akin to colonial conquest using huge loans instead of armed forces, although “throw-money diplomacy” is a catchy phrase. It certainly seems to have caught the attention of the Xi regime.

Sun, who is 84 years old, kept talking for as long as he could before being dragged him away.

“Here they come again, the police are here to interrupt again,” he told the stunned Voice of America audience, counting off the six police officers who barged into his home.

“What? What, did I say anything wrong?” he asked the police. “Listen to what I say, is it wrong? People are poor. Let’s not throw our money in Africa. The seven, eight of you here, listen up, throwing money like this is of no good to our country and society. It’s of no good.”

“What are you doing? What are you doing? Let me tell you, it’s illegal for you to come to my home,” he continued. The police riposted by hanging up his phone and making him disappear.

AFP noted that Sun, who is now one of the oldest dissidents in China, has been under constant surveillance for years:

He was a co-signer of the pro-democracy manifesto Charter 08—a quickly censored document that landed co-author and Nobel Peace Prize winner Liu Xiaobo in prison. Liu died last year, the first Nobel winner to die in custody since Nazi Germany.

In 2009, Sun was viciously beaten by authorities when he snuck past guards watching his building in an attempt to pay his respects to ousted Communist leader Zhao Ziyang—who opposed the use of force to quell the 1989 Tiananmen Square democracy protests — on the 10th anniversary of the former premier’s death.

Sun was also sentenced to seven years in prison for “attacking Great Leader Chairman Mao,” but was “rehabilitated” and returned to Shandong University in 1982, where he taught until retiring in 1994.

In a 2013 interview, Sun said that even when he was not effectively under house arrest at politically delicate moments, the police “watch me from the gate and follow me when I go out.”

“If I go to a meeting or to meet someone, they can track my cell phone to pinpoint my location, then the police escort me home,” he said.

The UK Guardian added that Sun has been repeatedly denied a passport without explanation, which prevented him from attending Liu’s Nobel Prize ceremony or visiting family abroad.

AFP also tried to get in touch with Sun using his mobile phone, home phone, and WeChat account, to no avail.

“In an apparent attempt to chill an open exchange of ideas and opinions, Chinese police may have forcibly stopped a Voice of America interview with Professor Wenguang Sun. There is currently no information about Professor Sun’s whereabouts, but we urge his immediate release if detained for engaging in what should be his right to free speech,” Rep. Chris Smith (R-NJ), chairman of the House Subcommittee on Africa, Global Health, Global Human Rights, and International Organizations, told Voice of America on Thursday.

“The Chinese and American people must continue to work toward a day when someone like Prof. Sun can openly share his opinions, via a free press, without fear of reprisal,” Smith added.

Senator Marco Rubio (R-FL) expressed his dismay on Twitter:

CNN asked the Chinese Foreign Ministry on Friday morning to comment on Sun’s case but did not receive an immediate reply. Several Western media reports filed on Friday quoted sources in Jinan who said Sun is under house arrest and is being held incommunicado.