China Detains US Seismologist Who Studied N. Korea Tests
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- Youlin Chen, a 54-year-old Chinese-born American seismologist and the only US citizen designated wrongfully detained in China, has been held nearly two years on espionage charges that could carry life imprisonment or the death penalty.
- Secretary of State Marco Rubio designated Chen as "wrongfully detained" on March 19, making his release a top US priority, though the Trump administration withheld a public announcement to allow high-level diplomacy.
- President Trump raised Chen's case with Xi Jinping during a May state visit to Beijing; Xi promised to look into it but no action has been taken, according to his wife Yufang Rong.
- Eric Lebson, a former US national security official advising Chen's family, believes Beijing wants to use his expertise to conceal underground nuclear weapons tests through a technique called decoupling; Chinese officials interrogated Chen more than 100 times about his work, his wife said.
- Chen was arrested November 5, 2024 at Beijing International Airport and charged with espionage May 1, 2025; he has lost 30 to 40 pounds and is denied adequate diabetes medication, according to his wife.
- The Trump administration in February accused China of trying to mask a low-yield underground nuclear test on June 22, 2020 using the same decoupling technique, which Beijing denies.
- The Foley Foundation estimates at least 12 Americans are unjustly held in China, including people under exit bans, framing Chen's case as part of a broader pattern.
Why it matters: Chen's detention sits at the intersection of two Trump-era flashpoints: US accusations that China has concealed underground nuclear tests, and hostage diplomacy involving at least 12 Americans. Xi's reported September Washington visit puts his case back on the negotiating table, and Lebson's theory directly ties his expertise to the very testing technique Washington says Beijing used.
