Another Chinese researcher has been accused of transporting biological samples into the U.S. This incident follows the recent detention of a University of Michigan student and her partner.
Chengxuan Han was arrested on Sunday at Detroit Metropolitan airport and charged with smuggling goods into the US.
Police allege Han sent four packages which ‘contained biological material related to round worms’ from China to the US.
The packages were sent between September 2024 and March 2025 and addressed to people linked to the laboratory at the University of Michigan.
Initially, Han denied having sent any packages, as stated in the court documents. Later, she claimed the parcels contained plastic cups instead of petri dishes.
Eventually, she confessed to mailing the samples, which she had gathered while conducting her Ph.D. studies in Wuhan, China, as per the documents.
The charges come less than a week after University of Michigan postdoctoral fellow Yunqing Jian, 33, was charged alongside Zunyong Liu, 34, for attempting to smuggle a weapon of ‘agroterrorism’ into the United States in a sinister plot allegedly tied to the Chinese Communist Party.
Liu arrived in the United States from China in July 2024 carrying four small baggies of Fusarium graminearum – a product responsible for causing billions of dollars worth of damage to livestock, wheat, barley, maize and rice globally each year.
All three of the accused have links to the same university laboratory.
Chengxuan Han was arrested on Sunday at Detroit Metropolitan airport and charged with smuggling goods into the US
Police allege Han sent four packages which ‘contained biological material related to round worms’ from China to the US
Two packages were sent – one in 2024 and another in 2024 – and addressed to people linked to the laboratory at the University of Michigan
Han was initially refused a visa to the US in March 2025, largely because she struggled to conduct her crucial visa interview in English, which is a requirement.
She was unable to answer basic questions about herself or her research field.
Two weeks later, Han applied again and during her second interview ‘spoke credibly about her educational background, current studies, and post graduate plans.’
Han is also accused of lying to border authorities who questioned her about the packages she had previously sent.
When officers attempted to check her phone, they learned it had been wiped three days before she arrived, the court documents state.
FBI boss Kash Patel issued a chilling warning following the initial arrest of Jian last week.
‘This case is a sobering reminder that the CCP [Chinese Communist Party] is working around the clock to deploy operatives and researchers to infiltrate American institutions and target our food supply,’ he said.
If successful, the plot ‘would have grave consequences… putting American lives and our economy at serious risk.’
The duo have been charged with conspiracy, smuggling, making false statements and visa fraud.
In a horrifying twist, the criminal complaint reveals that Jian may have been successful in smuggling pathogens into the United States years earlier.
University of Michigan postdoctoral fellow Yunqing Jian (pictured), 33, was charged alongside Zunyong Liu, 34, for the sinister plot
The research student, who reportedly had pledged her loyalty to the CCP, had indicated in messages to Liu that she previously carried a pathogen her shoe on a trip to America in 2022.
‘Electronic evidence also shows that Jian has been involved in smuggling packages of biological material into the United States on prior occasions,’ the complaint stated.
Separately, messages revealed she had arranged for another associate from China to mail her a book with a plastic baggie of the substance hidden inside in early 2024.
The horrifying revelations raise questions about what Jian and Liu were hoping to achieve with the pathogen.
The complaint also revealed that Jian had received funding from the Chinese government to conduct similar work on the same pathogen while she lived in China.
Her boyfriend is employed at a Chinese university where he also studies Fusarium graminearum.
The pair had ‘discussed the shipping of biological materials and research being done in the laboratory’ before he arrived in the United States.
Fusarium graminearum’s toxins cause vomiting, liver damage, and reproductive defects in humans and livestock if consumed.
‘The alleged actions of these Chinese nationals, including a loyal member of the Chinese Communist Party, are of the gravest national security concerns,’ US Attorney Jerome Gorgon Jr. said.
In July 2024, Liu was turned away at the Detroit airport and sent back to China after changing his story during an interrogation about the red plant material discovered in his backpack, per the FBI.
Messages revealed she had arranged for another associate from China to mail her a book with a plastic baggie of a substance hidden inside in early 2024
He initially claimed he knew nothing about the samples but later admitted he was planning to use the material for research at the lab, the complaint detailed.
The FBI said authorities found a scientific article on Liu’s phone that was titled, ‘Plant-Pathogen Warfare under Changing Climate Conditions.’
A week before he arrived in the US, Liu exchanged messages with his partner, who said: ‘It´s a pity that I still have to work for you,’ according to investigators.
FBI agents visited Jian at the campus lab in February, as she told them: ‘100% no,’ when asked if she had been assisting Liu with the pathogen at the lab.
But her text messages suggested she was in fact studying the product prior to her boyfriend’s arrival in the country.
The agency said it found a signed statement on her phone expressing her support for the Communist Party of China.
The university does not have federal permits to handle Fusarium graminearum.
In a statement, the University of Michigan said it did not receive ‘funding from the Chinese government in relation to research conducted by the accused individuals.’
‘We strongly condemn any actions that seek to cause harm, threaten national security or undermine the university’s critical public mission.’
Liu attempted to smuggle the pathogen through Detroit airport so he could study it at the University of Michigan laboratory where his girlfriend, Jian, worked, the complaint said
Gorgon Jr. described the allegations against the ‘two aliens’ as the ‘gravest national security concerns.’
The US does not have an extradition treaty with China, meaning Liu’s arrest is unlikely unless he returns.
The charges come as the Trump administration seeks to crack down on international students on US campuses, vowing last week to begin revoking the visas of some Chinese students, including those studying in ‘critical fields.’
China is the second-largest country of origin for international students in the United States, behind only India. In the 2023-2024 school year, more than 270,000 international students were from China, making up roughly a quarter of all foreign students in the United States.
‘Under President Trump’s leadership, the U.S. State Department will work with the Department of Homeland Security to aggressively revoke visas for Chinese students, including those with connections to the Chinese Communist Party or studying in critical fields,’ Secretary of State Marco Rubio said.
