Two Chinese nationals accused of smuggling biological materials into the United States appeared in court Friday as federal authorities fight to keep them detained in cases they say concern “national security.”

University of Michigan post-doctoral research fellow Yunqing Jian and Huazhong University of Science and Technology student Chengxuan Han were ordered to remain in federal custody as their separate cases remain ongoing. 

During the hearing, Han, who is accused of mailing packages containing biological materials to the University of Michigan’s laboratory, became visibly emotional and was seen choking back tears when she learned her preliminary hearing had been pushed to a later date.

In her brief detention hearing Friday, Han’s attorney said her client is consenting to detention without prejudice and will remain in federal custody. 

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“Ms. Han is presumed innocent, and we will await further proceedings to comment any further,” her attorney previously said in a statement to Fox News Digital. 

Han’s preliminary hearing was initially set for June 23, but was subsequently rescheduled for June 30. Both Han and Jian will remain in federal custody until their next hearings. 

Jian and her boyfriend, Chinese researcher Zunyong Liu, were charged this month after they first attempted to transport Fusarium graminearum, a “potential agroterrorism weapon” that can inflict dangerous health effects on humans, into the country in August 2022, prosecutors said. 

“The alleged actions of these Chinese nationals—including a loyal member of the Chinese Communist Party—are of the gravest national security concerns,” interm U.S. Attorney for the Eastern District of Michigan Jerome Gorgon said in a statement. “These two aliens have been charged with smuggling a fungus that has been described as a ‘potential agroterrorism weapon’ into the heartland of America, where they apparently intended to use a University of Michigan laboratory to further their scheme.”

Han was also arrested in June after allegedly mailing four packages containing undeclared biological material to individuals working in the University of Michigan’s laboratory from September 2024 to March 2025, according to the criminal complaint. 

In the case of Jian and Liu, a WeChat conversation allegedly revealed the couple brainstorming ways to transport the substance, with Jian ultimately deciding to stash the bags in her shoes. 

The fungus causes a “head blight,” described as a disease of wheat, maize, rice and barley, and is responsible for billions of dollars of economic losses throughout the world each year, according to the Department of Justice. If ingested by humans, the substance can cause vomiting, liver damage and “reproductive defects in humans and livestock.” 

Friday’s detention hearing lasted approximately two minutes, with Jian appearing in an orange jumpsuit and handcuffed around the waist. A federal judge adjourned the hearing until next Friday due to Jian’s request to seek private counsel. 

According to the criminal complaint, Jian initially received Chinese government funding for her work on the pathogen while studying at the University of Michigan and allegedly lied on her student visa application regarding her education plans in the U.S. Prosecutors allege Jian first attempted to smuggle the fungus into the U.S. in 2022, with one instance of her asking a third party to send her Fusarium graminearum in January 2024. 

Jian’s attorney did not immediately respond to Fox News Digital’s request for comment. 

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“There are usually no problems,” Jian said in a message to the third person. “Rest assured. I have mailed these before.”

The most recent smuggling attempt allegedly occurred in July 2024, when Liu arrived at the Detroit Metropolitan Airport to visit Jian, according to authorities. Upon landing, Liu was flagged by U.S. Customs and Border Protection (CBP) and subsequently searched. 

Authorities allegedly discovered “a wad of tissues crumpled up in a small pocket in Liu’s backpack,” according to the affidavit. 

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“The tissues concealed a note in Chinese, a round piece of filter paper with a series of circles drawn on it, and four clear plastic baggies with small clumps of reddish plant material inside,” the affidavit said.

The filter paper was sent for testing by the FBI, which revealed it contained Fusarium graminearum, according to authorities. The plastic baggies also allegedly carried material that was contaminated by the fungus, authorities said. 

“In addition, the laboratory identified 10 separate samples from the filter paper,” the affidavit said. “Each sample had a hand drawn circle around it, and each circle was labeled with a code containing letters and/or numbers. The sample labeled ‘06172’ was identified by the FBI laboratory to contain the DNA sequence for Fusarium graminearum.”

Liu allegedly denied carrying the pathogen, but later admitted to bringing it to the U.S. intentionally, officials said. He allegedly told authorities the pair planned to use the university’s laboratory to conduct research. 

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“These individuals exploited their access to laboratory facilities at a local university to engage in the smuggling of biological pathogens, an act that posed an imminent threat to public safety,” Cheyvoryea Gibson, Special Agent in Charge of the FBI Detroit Field Office, said in a statement. 

Both Jian and Liu are charged with conspiracy, making false statements, visa fraud and smuggling goods into the U.S. 

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“As one of the world’s leading public research institutions, the University of Michigan is dedicated to advancing knowledge, solving challenging problems and improving nearly every facet of the human experience,” the university previously said in a statement.

“We strongly condemn any actions that seek to cause harm, threaten national security or undermine the university’s critical public mission. It is important to note that the university has received no funding from the Chinese government in relation to research conducted by the accused individuals. We have and will continue to cooperate with federal law enforcement in its ongoing investigation and prosecution.” 

Han also made an appearance in federal court Friday. She is charged with smuggling goods into the U.S. and making false statements, according to court documents obtained by Fox News Digital.

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Authorities allege Han, a Ph.D. student at Wuhan’s College of Life Science and Technology in the Huazhong University of Science and Technology, mailed four packages containing undeclared biological materials to staff members at the University of Michigan’s laboratory. 

Han was arrested on Sunday while traveling to the Detroit Metropolitan Airport from Shanghai on a J1 visa. Upon her arrival, Han was searched by CBP officers, and subsequently confronted about the packages. 

According to the criminal complaint, Han allegedly denied mailing the packages, but later admitted she had sent them after being pressed by authorities. Han initially told CBP officers the packages only contained plastic cups – not petri dishes – and a book, according to court documents. 

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Han allegedly confessed to sending the packages, which contained roundworm-related biomaterials, telling FBI and Homeland Security officials that she had initially lied to CBP agents. Officers also discovered Han’s electronic devices had been wiped of their content three days before her arrival in the U.S. 

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“The alleged smuggling of biological materials by this alien from a science and technology university in Wuhan, China – to be used at a University of Michigan laboratory – is part of an alarming pattern that threatens our security,” Gorgon said in a statement. “The American taxpayer should not be underwriting a PRC-based smuggling operation at one of our crucial public institutions.”   

Fox News’ Olivianna Calmes and Peter D’Abrosca contributed to this report.