American Seismologist Detained in China for Nearly Two Years on Espionage Charges
Yulin Chen, a 54-year-old American seismologist originally from China, has been secretly detained in China since November 5, 2024, on espionage accusations related to his research on North Korea's underground nuclear tests. Chen, who became a U.S. citizen in 2011, was arrested at Beijing International Airport just before boarding a flight back to his home in Boston after visiting family and lecturing at Chinese universities. His family and advocacy groups revealed his detention after more than 600 days of silence, aimed at allowing behind-the-scenes diplomatic efforts by U.S. officials to secure his release.
Chen's wife, Yufang Rong, described harsh detention conditions early on, including being forced to sit on a hard bench all day without medication for his diabetes and other health issues. He has lost significant weight and receives inadequate food and low-quality medicine. Although formally charged with espionage on May 1, 2025, Chen has yet to stand trial. U.S. embassy officials have visited him multiple times, but Chinese officials have always been present, limiting his ability to speak freely.
The U.S. government, including Secretary of State Marco Rubio, has officially declared Chen's detention unjust, making his release a top priority. The case has been raised in high-level talks, including a May 2025 meeting between former President Donald Trump and Chinese President Xi Jinping in Beijing, where Trump requested Chen's release without success. Trump has invited Xi to Washington in September 2026, where the issue is expected to resurface.
Chen’s research, funded by the U.S. State Department and Air Force research labs, focused on detecting and analyzing seismic signals from North Korea’s nuclear tests, using publicly available Chinese data. Despite this, Chinese authorities accuse him of espionage, possibly aiming to exploit his expertise to improve their own nuclear test concealment techniques. Human rights groups warn that China’s broad state secrets laws allow retroactive classification of public data, complicating cases like Chen’s.
Chen’s wife fears a closed trial and conviction regardless of evidence, emphasizing that he never held U.S. security clearance or conducted classified work. His detention adds strain to already tense U.S.-China relations amid ongoing efforts to stabilize ties following recent trade conflicts. Advocacy groups note Chen is among at least a dozen Americans unjustly held in China, but he is the only one officially recognized as wrongfully detained by the U.S. government.
