Chen Youlin, 54, a U.S. citizen and seismologist, was arrested during a trip to Beijing in November 2024, according to Global Reach, a hostage advocacy group. His family says they have not seen any indication that Beijing plans to release him. Chen, who specializes in identifying nuclear tests using seismological data, has worked on projects funded by the U.S. government and has studied seismic data from North Korea, a country under international sanctions for its nuclear program.

Allegations of Espionage and Concerns Over Health

Chen’s wife, Rong Yufang, a seismologist herself, stated that the espionage allegations are “both wrong and inconsistent with the public and collaborative nature of the work” he has done. She noted that his work with Chinese colleagues was always transparent and not conducted in secrecy. Rong also revealed that Chen has not been allowed to speak to a lawyer for the first 13 months of his detention and has been interrogated more than 100 times about his work.

Chen, who became a U.S. citizen in 2011, currently lives in Boston, Massachusetts. His wife added that she has not been able to speak with him for over 600 days and is worried about his health and well-being. The Foley Foundation, another U.S.-based advocacy group, raised concerns about his health, noting that he has diabetes, high blood pressure, and high cholesterol. They said he needs reliable medical care, which is not available while he is in custody.

Context of Nuclear Test Monitoring and Diplomatic Tensions

Chen’s work, which has included analyzing seismic data from across Asia, is linked to improving methods for monitoring nuclear tests and estimating their yields. In a statement, Global Reach said there are “suspicions within the U.S. government that Chen’s arrest was spurred by China’s conduct of nuclear tests in violation of the Thorough Nuclear Test Ban Treaty.” The group also suggested that Chen’s expertise could help China understand U.S. seismic detection methods and develop ways to circumvent the treaty.

The Full Nuclear Test Ban Treaty seeks to ban all nuclear explosion tests on Earth, but several nuclear-capable countries, including the U.S. and China, have not ratified it. Both countries have established voluntary moratoriums on explosive nuclear testing. In June 2020, the Trump administration accused China of conducting a covert underground nuclear test at the Lop Nur facility. China dismissed the claims as “unfounded and politically motivated.”

Responses from the Chinese Government and U.S. Officials

When asked about the case at a daily press briefing, China’s foreign ministry stated that its judicial authorities handle cases “in accordance with the law.” Spokesman Lin Jian said there is “no such thing as so-called wrongful detention.” In China, espionage convictions can lead to life imprisonment or the death penalty. The U.S. government has designated Chen as the only U.S. citizen currently considered “wrongfully detained” by the Chinese government.

Senator Edward Markey, a Democrat from Massachusetts, expressed concern over how China has treated Chen. He said that the detention “has undermined [China’s] partnership [with the U.S.] and may deter other academics from engaging with their colleagues in China.” Markey added that he hopes increased attention on the case will lead to Chen’s release.

Details about Chen’s arrest emerged a month after China confirmed the detention of another U.S. scholar, Min Zin, a director at a Myanmar-focused think tank. Beijing has accused Min Zin of spying and endangering Chinese national security. This marks the second high-profile academic detention by Chinese authorities in recent months.