Key facts
- American seismologist Youlin Chen has been detained in China for nearly two years.
- Chen is accused of spying and faces trial.
- The U.S. State Department has designated Chen as "wrongfully detained."
- Chen's research on North Korean nuclear test seismic signatures was funded by the U.S. State Department and Air Force Research Laboratory.
- Chen was arrested in November 2024 at Beijing International Airport before returning to Boston.
- He was charged with espionage in May 2025.
A Chinese-born American seismologist, Youlin Chen, has been detained in China for nearly two years and faces trial on spying charges, according to his wife, U.S. lawmakers, and advocacy groups. Chen, 54, who became a U.S. citizen in 2011 and lives in Boston, has published U.S.-funded work on detecting North Korean nuclear tests. His wife, Yufang Rong, stated that Secretary of State Marco Rubio designated Chen as "wrongfully detained" on March 19, making his release a top U.S. priority. The Trump administration has withheld a public announcement to allow space for diplomacy, with a U.S. source familiar with the case emphasizing the focus on gaining his release from "unjustifiable detention."
Rong reported that President Trump raised her husband’s detention with Chinese leader Xi Jinping during a state visit to Beijing in May, and Xi promised to investigate. However, no action has been taken by the Chinese government. U.S. embassy officials have visited Chen, but Chinese officials' presence has prevented free conversation. He was interrogated over 100 times about his research on the seismographic signatures of North Korean nuclear tests. Experts believe China may seek to use Chen's expertise to improve its ability to conceal underground nuclear weapons tests through decoupling, a technique the U.S. accused China of attempting to mask a test with in June 2020. Chen, employed by a U.S. government contractor, has never held a U.S. security clearance, and his research was publicly available and funded by the State Department and Air Force Research Laboratory.
Chen was arrested on November 5, 2024, at Beijing International Airport as he was preparing to return to Boston after visiting family and lecturing. His wife described harsh initial detention conditions and stated he has lost significant weight and receives poor nutrition and medication. He was charged with espionage on May 1, 2025, and his case is expected to be discussed during a potential visit by President Trump to Washington in September. U.S. Senator Ed Markey expressed deep concern for Chen's safety and wellbeing, hoping increased attention will lead to his release.