The Chinese biology researcher accused of lying on applications to obtain a visa and gain access to the United States is now in custody and expected to make a court appearance via video conference Monday afternoon, the U.S. Attorney's office said.

Tang Juan, who was staying in the Chinese consulate in San Francisco, according to the FBI, and three other researchers are accused of concealing their identities as members of China's People's Liberation Army. All have been charged with visa fraud.

Tang, a researcher at the University of California, Davis, stated on her J-1 visa application that she "had never served in the military, but open source investigation revealed photographs of her in the uniform of the Civilian Cadre of the PLA [People's Liberation Army], and that she had been employed as a researcher at the Air Force Military Medical University, which is another name for FMMU [Fourth Military Medical University]," the FBI claimed.

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According to a June 20 interview with FBI agents, Tang "denied serving in the Chinese military, claimed she did not know the meaning of the insignia on her uniform, and that wearing a military uniform was required for attendance at FMMU because it was a military school."

The FBI said it executed a search warrant at Tang's home and found a trove of evidence of Tang's PLA affiliation.

"The FBI assesses that at some point following the search and interview of Tang on June 20, 2020, Tang went to the Chinese consulate in San Francisco, where the FBI assesses she has remained," the bureau said.

The FBI filing against Tang came as part of a document that cited a slew of other episodes in which Chinese nationals allegedly lied on their visa applications by concealing their military ties.

The FBI said it has interviewed visa holders in more than 25 U.S. cities who are suspected of lying about their connection to China. The bureau believes the deception is part of an ongoing government-orchestrated effort to steal research on a variety of topics from American universities for China's economic gain.

"Defendant's case is not an isolated one, but instead appears to be part of a program conducted by the PLA – and specifically, the FMMU or associated institutions – to send military scientists to the United States on false pretenses with false covers or false statements about their true employment," the FBI said, singling out Chen Song, another suspected spy.

In that case, prosecutors said Chen, a visiting medical researcher at Stanford University, entered the U.S. on a work-study visa in December 2018, identifying herself as a neurologist who was going to the California school to conduct research on brain disease.

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In her visa application, Chen states she had served in China's armed forces from September 2000 through June 2011 and listed her current employer as a civilian hospital in China. However, the FBI said research articles Chen submitted with her visa application identified her employers as hospitals controlled by the Chinese military.

An online profile of Chen on a Chinese website identifies her as a neurologist studying myasthenia gravis at a Chinese air force hospital and includes a picture of her in a military uniform.

As the allegations of visa fraud play out in court, the U.S. has ordered China to close its consulate in Houston, a move Beijing denounced as "outrageous."

The physical closure of the consulate, one of six China has in the United States, is a bold step in the escalating tensions between the two superpowers that have not only been strained by assigning blame over the coronavirus pandemic but also by disputes over human rights, trade and escalations made by Beijing in the South China Sea.

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In retaliation for closing the China consulate in Texas, China on Friday ordered the closure of the U.S. consulate in the western city of Chengdu.

“The measure taken by China is a legitimate and necessary response to the unjustified act by the United States,” the foreign ministry said in a statement.

Fox News' Nick Kalman contributed to the report.