A Chinese Ph.D. student, Chengxuan Han, pleaded no contest on August 19, 2025 to multiple federal charges—including smuggling biological materials into the United States and making false statements to Customs and Border Protection (CBP) officials. Han, a doctoral candidate at Huazhong University of Science and Technology in Wuhan, China, had shipped four improperly documented packages containing biological materials related to roundworms to researchers at the University of Michigan between 2024 and 2025.
Upon arriving at Detroit Metropolitan Airport on a J‑1 visa in June, Han was stopped for inspection. She initially lied to CBP officers, downplaying her knowledge of the packages and mislabeling their contents as plastic plates or books. Authorities discovered that data on her electronic device had been erased just days before her arrival. Later, during further questioning, she admitted to both sending the packages and misrepresenting their contents.
If convicted, Han faces a prison term of up to 20 years for smuggling and an additional five years for making false statements. Her sentencing is scheduled for September 10, 2025.
This case marks a troubling pattern. Earlier this year, two other Chinese nationals—postdoctoral researcher Yunqing Jian and her boyfriend Zunyong Liu—were charged with conspiring to smuggle Fusarium graminearum, a toxic agricultural fungus and potential agroterrorism agent, into the United States via the University of Michigan. Han’s arrest is the third in a series of such incidents, prompting heightened federal concern over biosecurity risks tied to foreign researchers.
Justice Department officials underscored the severity of the offenses. U.S. Attorney Jerome Gorgon Jr. condemned Han’s actions as part of an “alarming pattern that threatens our security,” stressing that American taxpayers should not bear the burden of facilitating illicit biological transfers.
