US expert on underground nuclear tests held in China for 18 months

By Mike Valerio, Simone McCarthy, CNN Beijing (CNN) — An American scientist who has studied underground nuclear tests has been detained in China for more than 18 months on spying charges, according to his supporters and a US lawmaker. Youlin Chen, a seismologist, has been “wrongfully detained” since November 2024, US Senator Edward Markey said