US seismologist who studied North Korean nukes detained in China, wife fights ‘unjust’ charges

An American seismologist who spent his career studying North Korean nuclear tests has been locked up in China for years and is expected to be hauled in front of a court over spying charges, his wife and advocates said. 

Youlin Chen, 54, was cuffed by Chinese authorities on Nov. 5, 2024 at Beijing International Airport while attempting to fly home to Boston after visiting his family and lecturing on seismology. 

He was then hit with espionage charges on Mar. 1, 2025. 

While Chen was born in China, he became a US citizen in 2011. He’s being held unjustly in a country that’s not his own – with trial for espionage looming over his head, his wife Yufang Rong and a team of advocates told Reuters. 

“I believe they will convict him no matter what and the trial will be behind closed doors,” Rong told the outlet. 

US embassy officials have visited Chen, but his wife said that Chinese officials are always present when they do, preventing her husband from speaking freely. 

Rong and advocates say Chen’s wrongful detention is based around his scientific work as a seismologist, studying earthquakes and other seismic waves in the Earth’s ground. 

Family and advocates said Chen’s scientific research into secret North Korean nuclear tests is what ended up drawing the ire of Chinese authorities. 

They cite a December 2020 paper Chen published – written while he was a US government contractor for the State Department – using open source data available in China to examine the earth-shaking differences between earthquakes and secret underground nuclear weapons being tested by China’s ally North Korea. 

Human rights orgs said that they’re worried that part of China’s prosecution of Chen may involve the use of a law that retroactively criminalizes the use of what was once publicly available data.  

Chen has been interrogated nearly one hundred times for his seismological research, his wife said. 

Eric Lebson, who leads the hostage advocacy organization Global Reach and is advising Chen’s family, suggested that Chinese authorities may be particularly interested in using Chen’s knowledge in learning how to better hide the seismic signs of their own nuclear tests. 

China allegedly carried out an underground nuclear test in 2020, which was quickly caught by American authorities and caused a strain on already fraught relations with the US.  

Chen’s case has caught the attention of higher-ups in the Trump administration, including Secretary of State Marco Rubio, who declared Chen as “wrongfully detained.”

Chen’s wife Rong has also said that the Trump administration is engaging in sub rosa talks with the Chinese government to release Chen, having brought up the matter with Chinese leader Xi Jinping. 

But the Trump administration has not publicly commented about the supposed talks, and a US source told Reuters they couldn’t confirm Trump had broached the matter with Xi. 

But another US source also told the outlet they’re “focused on gaining his release from [Chen’s] unjustifiable detention.”

Chinese authorities have also pushed back the claim that Chen’s detention is “unjust.”

Chinese foreign ministry spokesman Lin Jian has said “there is no so-called wrongful detention,” and that the matter is handled according to the law. 

But as the matter is hashed out by American and Chinese diplomats, Chen continues to sit in prison in “harsh conditions,” according to his wife. 

Massachusetts Sen. Ed Markey, who first brought the plight of Chen to Secretary Rubio’s attention, told Reuters he’s “deeply concerned” about Chen’s well-being. 

“It is my hope that increased attention on his unjust detention will force the Chinese government to do the right thing and release Dr. Chen,” Markey told the outlet in a statement.