The United States said Wednesday it had charged four Chinese intelligence officers with helping an American citizen spy on prominent critics of China.
Together all five conspired to silence Chinese dissidents, pro-democracy activists and human rights leaders, New York prosecutors said in a statement.
The US citizen -- 73-year-old Shujun Wang, a prominent Chinese-born academic living in New York -- was arrested in March on suspicion of acting as an agent of the Chinese government.
The indictment, dated Tuesday, accuses him of using the pro-democracy organization that he founded to "covertly collect information about prominent activists and human rights leaders."
Federal prosecutors say he passed on the information to his "handlers" inside China's Ministry of State Security (MSS): Feng He, Jie Ji, Ming Li and Keqing Lu.
The agents directed Wang to target Hong Kong pro-democracy activists, advocates for Taiwanese independence, and Uyghur and Tibetan activists, the Brooklyn prosecutors said.
He passed on messages to the four "using encrypted messaging applications and emails, as well as during face-to-face meetings" in China, according to the department of justice statement.
Wang faces up to 20 years in prison if convicted. His four co-defendants remain at large.
Wang was arrested on March 17 as US Attorney for the Eastern District of New York Breon Peace announced charges in three separate cases.
In one, MSS agent Lin Qiming, 59, was accused of conspiracy to harass a congressional candidate who was a student leader of the pro-democracy demonstrations in Tiananmen Square in 1989.
In the other case, Fan "Frank" Liu, 62, of New York; Matthew Ziburis, 49, of New York; and Qiang "Jason" Sun, 40, of China, were charged with conspiring to act as agents of the Chinese government.