On July 9, Li Yunhai, a 35-year-old Chinese postdoctoral researcher, was stopped by U.S. Customs and Border Protection and Homeland Security Investigations agents at George W. Bush International Airport in Houston as he prepared to board a flight back to China.

About 50 to 90 gigabytes of undisclosed research data related to breast cancer vaccine projects funded by the U.S. Department of Defense and the National Institutes of Health were found on his laptop and mobile phone.

Li Yunhai, who has been working on breast cancer research at the University of Texas MD Anderson Cancer Center since 2022 and is funded by the US Department of Defense and the National Institutes of Health, is accused by prosecutors of stealing trade secrets and forging documents by uploading undisclosed research data to his personal Google Drive and Baidu Netdisk in China.

Investigation showed that during his tenure at MD Anderson Cancer Center, Li Yunhai also received research funding from the First Affiliated Hospital of Chongqing Medical University in China, but did not declare this external funding source as required. He even claimed in his confession that "these data should have belonged to me" and said he planned to continue breast cancer vaccine research in China.

However, under U.S. law, research results supported by federal funds are usually attributed to funding agencies or executing units, not individual researchers. Li Yunhai has signed a confidentiality agreement prohibiting the disclosure of information to anyone outside the cancer center and stated that he has not accepted foreign research funding.

After the case came to light, Li Yunhai was charged with stealing trade secrets, a third-degree felony punishable by up to 10 years in prison and a $10,000 fine, and altering government records, a misdemeanor punishable by up to one year in prison and a $4,000 fine.

Li Yunhai has posted a bail of US$5100 and surrendered his passport. He is restricted from leaving the country and is currently under GPS location monitoring. Prosecutors said that the case is still under investigation and it is not ruled out to transfer it to federal prosecutors for additional more severe charges.

This case occurred against the backdrop of intensified scientific and technological competition between China and the United States. In April 2025, the National Institutes of Health issued new regulations prohibiting "countries of concern" such as China from accessing its controlled access data repositories and related data, especially for data in the fields of biomedicine and personal privacy.

This policy has left Chinese researchers facing challenges such as closing direct application channels, lengthening the approval process and potentially completely disrupting access rights. At the same time, the Department of Justice amended the Anti-Economic Espionage Law to include "cross-border flow of data" in the scope of national security review. Chinese AI scientists have been interrogated while transiting in the United States.

China's Ministry of Science and Technology has issued non-public recommendations to leading enterprises and research institutions in the field of artificial intelligence, requiring core researchers to "not go to the United States unless necessary" to prevent technology leakage and the risk of executives being detained.

The future development of the case may affect the direction and depth of Sino-US scientific research cooperation. If Li Yunzhou is convicted of several crimes, he could face long imprisonment; if federal prosecutors add additional charges, the penalty could be further increased. The incident may also exacerbate Sino-US data control measures in the biomedical field, complicating scientific research exchanges and cooperation.

For multinational researchers, it is crucial to clarify the ownership of intellectual property rights, abide by confidentiality agreements, and truthfully declare external funding relationships. The Li Yunhai case warns that there is often a gap between personal research efforts and legal provisions, especially at a time when international scientific research cooperation and competition are intertwined.