How Beijing helped free 3 Chinese scientists jailed in US ‘worm’ smuggling case

Beijing Steps In As US Drops Case Against 3 Chinese Researchers Over ‘Worms’

A federal case once projected as a national security success by the administration of US President Donald Trump has been quietly dropped, allowing three Chinese research scholars to return home after spending more than three months in jail.

The three scientists, who had been temporarily working at the University of Michigan, were accused of helping a colleague smuggle biological materials into the United States. However, the Justice Department moved to dismiss the charges on February 5, and a federal judge in Detroit approved the request. The development was first reported by the Associated Press, which cited defence lawyers as saying that Beijing intervened in the matter.

What were the allegations?

Xu Bai and Fengfan Zhang were charged with conspiring to assist another researcher who allegedly shipped biological samples from China before arriving in 2025 for temporary lab work at the University of Michigan. A third researcher, Zhiyong Zhang, faced charges of making false statements to federal investigators.

Prosecutors had initially described the case as a national security concern. Attorney General Pam Bondi said at the time that authorities must remain vigilant when foreign nationals attempt to “advance a malicious agenda.”

The materials in question were later described by defence lawyers as tiny, transparent worms commonly used in laboratory research. According to the defence, the organisms posed no threat and had a limited lifespan.

Charges dismissed after diplomatic intervention

All three scholars were held in custody for over three months while the case proceeded in federal court. The charges were unexpectedly dropped at the Justice Department’s request.

“The dismissal came as a pleasant surprise,” defence lawyer John Minock said. “We don't know the details. What we were told was that there was some kind of intervention by the Chinese consulate in Chicago.”

Another attorney, Ray Cassar, said he had been negotiating a misdemeanor plea deal for Fengfan Zhang when prosecutors withdrew the case.

“We get this phone call saying China is negotiating with the US over these three students. Serious talks,” Cassar said. “These were kids studying for their PhDs. The last thing you want to do is destroy their careers. ... Was it the proper thing to do? Absolutely.”

Defence attorney Mark Satawa said the Chinese Consulate’s involvement appeared to influence the outcome. He also noted that Zhiyong Zhang, a Mandarin speaker, did not have a translator during questioning by investigators.

The US Attorney’s Office in Detroit declined to comment on the reasons behind the dismissal or on China’s reported role. The Chinese embassy in the United States has not issued a public statement.

Background and related cases

According to defence lawyers, the worms were routinely used to study chemical reactions and light sensitivity. Ray Cassar said the packages were not properly labelled because Chengxuan Han, the scientist who sent them, likely wanted to prevent delays during inspection.

“There was no intention of doing anything nefarious,” Cassar said. “The worms have been consistently used for studying chemical reactions and light sensitivity.”

In September, Han pleaded no contest to smuggling and making false statements. She served three months in jail before being deported to China.

In a separate but similar case, another temporary researcher, Yunqing Jian, pleaded guilty to charges related to a common plant fungus and was deported after five months in custody. An expert who reviewed evidence in that matter said the materials involved posed no risk to public safety.

The dismissal of charges against the three Chinese scholars marks an unexpected reversal in a case that had previously been framed as part of a broader effort to safeguard US national security.