A pair of Chinese nationals are facing federal charges for allegedly smuggling a dangerous crop pathogen into the United States and attempting to conduct unauthorized research at a University of Michigan laboratory, according to an FBI affidavit unsealed this week.
The complaint, filed by FBI Special Agent Edward Nieh, names Yunqing Jian, a postdoctoral researcher at the University of Michigan, and her partner Zunyong Liu, a faculty member at Zhejiang University in China. Both are accused of conspiracy, smuggling, and making false statements. Liu faces an additional charge of visa fraud.
At the centre of the case is Fusarium graminearum, a fungus that causes head blight in cereal crops like wheat and barley. It has been classified in scientific literature as a potential agroterrorism agent due to its devastating economic impact and ability to produce toxins harmful to humans and animals.
A Pathogen Hidden in Tissues
On In July of 2024, Liu arrived at Detroit Metropolitan Airport from Shanghai. During a customs inspection, officers discovered multiple plastic bags containing reddish plant material and a piece of filter paper hidden in crumpled tissues inside Liu’s backpack. The filter paper was labeled with hand-drawn circles and coded identifiers. Initially denying knowledge of the samples, Liu eventually admitted he was smuggling Fusarium graminearum into the country to conduct research at the University of Michigan, where Jian was employed. He confessed to hiding the materials because he was aware of USDA restrictions on importing plant pathogens.
Liu, who was in the United States on a B2 tourist visa—a category that explicitly forbids research activities—had not applied for the mandatory USDA permit required to bring the pathogen into the country.
While Liu claimed to be acting alone, FBI analysis of WeChat messages between Liu and Jian revealed a different story. A conversation from May 2024 shows Jian warning Liu that one of his biological samples had been discovered at the university lab: “Your cell death phenotype plants were seen by [the principal investigator]… I didn’t dare tell her it was Fg [Fusarium graminearum]. That’s even more serious.”
Other messages indicate that Jian was expecting seeds to arrive and had previously concealed biological materials in packages sent from China. In one exchange from August 2022, Jian described smuggling seeds into the U.S. by hiding them in her boots.
Smuggling by Mail
Jian is also accused of orchestrating a separate attempt to smuggle a sample labeled “06172”—identified by the FBI as a live strain of Fusarium graminearum—by instructing a colleague in China to embed filter paper in a statistics textbook and ship it to her home address in Ann Arbor.
Photos of the concealed material matched a package intercepted by U.S. Customs and Border Protection in Louisville, Kentucky, in January 2024. According to CBP, the textbook contained fifteen circles of filter paper, each holding an unknown biological substance.
When FBI agents interviewed Jian in February 2025, she repeatedly denied knowledge of the smuggling attempt. Agents found these denials inconsistent with her digital communication. During the interview, Jian also appeared to delete a WhatsApp conversation, and a forensic search later found missing WeChat message history coinciding with the July 2024 smuggling incident.
