Tang Yuanjun, 67, swam to a Taiwan-controlled island more than 20 years ago before being granted political asylum by the United States.
He was charged on Wednesday with acting as an agent for the People’s Republic of China in the United States from 2018 to 2023, the justice department said in a statement.
Tang completed “tasks at the direction of the PRC’s Ministry of State Security (MSS), which is the PRC’s principal civilian intelligence agency,” the department said.
Tang provided MSS officials with information on “individuals and groups viewed by the PRC as potentially adverse” to its interests, including “prominent US-based Chinese democracy activists and dissidents”.
He is also accused of lying to the Federal Bureau of Investigation for claiming he no longer had access to an email account used to communicate with his MSS handler.
He was arrested on Wednesday and was scheduled to appear before a district judge.
Tang, a native of China’s northeastern Jilin province, had been sentenced to 20 years for taking part in the 1989 democracy movement that resulted in the deadly Tiananmen Square crackdown in Beijing.
He was released after serving eight years.
Tang remained active in advocating for democracy in China and was repeatedly detained, questioned, and harassed by the authorities before fleeing to Taiwan, according to a Taipei-based rights group that helped with his asylum bid in 2002.