Zhu is a citizen of China who lived in Clovis at the time of the lab’s discovery, according to prosecutors. His romantic and business partner, 38-year-old Zhaoyan Wang, was also named in the indictment.

Their lawyer did not immediately respond to a request for comment.

The two were linked to a limited partnership based in Oakland that owns the property in question in downtown Reedley, California, that was secretly used by Universal Meditech Inc. and Prestige Biotech Inc.

The companies stored dozens of refrigerators filled with vials of blood, viruses and other infectious agents; containers of laboratory chemicals; hundreds of laboratory mice; and an array of other stored laboratory equipment.

The defendants were accused by prosecutors of defrauding buyers of Covid-19 test kits between August 2020 and March 2023.

They allegedly imported “hundreds of thousands” of test kits from Ai De Ltd., which was a company in China that they controlled, and falsely represented to the buyers that the test kits were made in the United States, according to a news release.

Prosecutors said the pair told regulators the kits were pregnancy tests to get them into the US.

They represented to buyers they could make as many as 100,000 kits a week in the US approved by the Centres for Disease Control and Prevention, according to federal prosecutors. They avoided showing the buyers around the lab by claiming it was under construction.

Zhu remained in custody pending his trial, according to the Justice Department. Wang was not in custody.

Zhu faces maximum statutory penalties of 20 years in prison for the conspiracy and wire fraud charges, and an additional three years in prison for the distribution of adulterated and misbranded medical device charges, the news release said.

The next hearing was set for September 11.

Tang was subsequently granted political asylum in the US where he “regularly participated in events” with fellow Chinese dissidents, according to the criminal complaint.

In 2018 and 2023, and possibly on other occasions, however, Tang worked as an agent for MSS, China’s principle civilian agency handles foreign intelligence, counter-intelligence, espionage and political security activities.

Prosecutors allege that Tang agreed to cooperate in a bid to see his family back on the mainland. They add that after a visit home in 2018, he was introduced to an unnamed MSS official at which point the MSS provided money to his family.

The Chinese embassy in Washington said it was not aware of specific details involving the case.

“But in recent years, the US government and media have frequently hyped up the so-called ‘Chinese agents’ narratives, many of which have later been proven untrue,” said spokesman Liu Pengyu.

“China requires its citizens overseas to comply with the laws and regulations of the host country, and we firmly oppose the [groundless] slandering and smearing targeting China,” he added.

According to the Justice Department filing, Tang used an email account, encrypted chats, text messages and audio and video calls to communicate with and receive instructions from an MSS intelligence officer.

Of particular interest to Beijing, US prosecutors said, were details on US-based Chinese democracy activists, dissidents and groups that China saw as “potentially adverse” to its interests; events planned to commemorate the 2021 June 4 anniversary; and details of the US asylum process.

“He also travelled at least three times for face-to-face meetings with MSS intelligence officers and helped the MSS infiltrate a group chat on an encrypted messaging application,” the filing said.

The chat platform, with some 140 participants, was reportedly used to communicate about activist issues and criticise the Chinese government.

Tang also allegedly provided MSS with information about an unnamed Congressional candidate – reportedly a Chinese dissident and human rights activist – including details on the candidate’s campaign team and fundraising.

During a 2022 meeting, prosecutors allege, the MSS officer inserted a monitoring device in one of Tang’s cellphones that “caused any photo, screenshot, or voice memorandum generated or captured on the compromised phone to be immediately transmitted” to the officer.

The Justice Department said that the FBI is still investigating, but that law enforcement agencies have recovered instructions that MSS sent Tang as well as photographs, videos and documents Tang collected or created to send back to the spy agency from several electronic devices.

In recent years, Chinese President Xi Jinping has made security a cornerstone of his administration and significantly expanded the power of the MSS.

In May, MSS warned on its WeChat account against “quite deceptive” foreign operatives seeking to steal hi-tech Chinese industrial secrets.

Agencies investigating and prosecuting the Tang case include the FBI’s national security unit and the Justice Department’s counter-intelligence and export control section.

Neither Tang, who was arrested in the New York City borough of Queens, nor any lawyer he has hired, could be reached. New York, where Tang has lived for two decades, has the largest concentration of Chinese-Americans – more than half a million – of any US city.