American officers caught a person who landed in the United States carrying vials of a coronavirus from China, according to documents from the Department of Homeland Security (DHS) and other agencies made public on July 24.
U.S. Customs and Border Protection (CBP) officers found the vials of porcine epidemic diarrhea virus and antibody genetic material on a courier, whose name was redacted, during an inspection at Detroit Metropolitan Airport on Nov. 28, 2018, according to the documents.
The courier was not authorized to carry the vials, which had been obscured in carry-on baggage with a combination of paper towels and wax film, officials said. The courier said that he was given the vials by Yusen Zhou, who worked for China’s Academy of Military Medical Sciences, and that the vials were intended for Fang Li, a researcher at the University of Minnesota who has co-written papers with Zhou.
Laboratory testing from DHS and the FBI confirmed that porcine epidemic diarrhea virus spike protein was in the vials, as well as partial immunoglobulin heavy chain precursor messenger ribonucleic acid.
Porcine epidemic diarrhea virus is a highly dangerous coronavirus that causes illnesses and deaths in swine.
The attempted delivery came just one month after a student in Li’s lab offered to send live porcine epidemic diarrhea virus to an American researcher, Ralph Baric, according to emails also released on Friday.
It also came six months after Dr. Zhengli Shi, a virologist at the Wuhan Institute of Virology, asked Li to have a student take coronavirus antibodies from the United States to China, the emails showed. Li said that plan was not a good idea “given the current tension between USA and China,” but suggested another scientist ship the antibodies to China.
CBP officials said in a report dated June 15, 2020, that Li had received funding from the National Institutes of Health. They said that some of his research fellows and collaborators have connections to the Chinese military and may pose a risk to U.S. national security.
“Additional investigation is necessary to determine if LI’s research, and any resulting scientific discoveries and advances, are for the benefit of the United States or for China, and if the intention of LI’s research fellows/affiliates are to act as unconventional collectors of information,” they said.
Li and CBP did not return requests for comment by time of publication.
In 2021, the same courier was stopped at the Detroit airport before flying to China and CBP officers found 132 undeclared vials they said likely contained a species of fly regularly used in biological research, as well as a computer issued by an unidentified research institution that belonged to another person, in addition to credentials to log onto the computer.
The courier was described as a teacher at Zhengzhou University in China, and that he completed work with an U.S. facility whose name was redacted. He said he did not declare the flies because “he was not sure he [was] allowed to transport” them on the plane, the CBP documents said. The vials were seized and the courier was allowed to leave.
Sen. Rand Paul (R-Ky.), who released the documents, said in a statement that he found “undeclared coronavirus materials moving between American and Chinese labs as far back as 2018—years before anyone had heard of COVID-19.”
Federal prosecutors in 2024 and 2025 charged other Chinese nationals over trying to smuggle viruses into the United States. Some of them, such as Youhuang, who was a post-doctoral researcher at Indiana University, have pleaded guilty and were sentenced to time in prison.
