A top New York state government aide secretly helped the Chinese government access an official call about Covid-19 while enjoying a lavish lifestyle as an undercover agent for Beijing, according to a US indictment.

Over a period of roughly 14 years, Linda Sun rose through the ranks to become deputy chief of staff to the governor.

But according to federal prosecutors, the 41-year-old used her position to aid Chinese officials, including by blocking Taiwanese diplomats from contacting the state government and covertly sharing internal documents with Beijing.

In return, China allegedly showered Ms Sun and her husband, Christopher Hu, with millions of dollars in kickbacks that helped them buy a $4.1m (£3.1m) house in New York and perks including special home deliveries of salted duck.

They also bought a $2.1m ocean-view condominium in Honolulu, Hawaii, and luxury vehicles including a 2024 Ferrari Roma sports car, according to the indictment.

The couple pleaded not guilty on Tuesday in a Brooklyn federal court to a range of charges, from failing to register as a foreign agent to visa fraud and money laundering.

US law requires that individuals acting for or in the interests of foreign countries or political parties register as foreign agents.

Ms Sun never did – and, according to prosecutors, the Chinese-born naturalised citizen “actively concealed that she took actions at the order, request, or direction” of Chinese government officials and representatives.

In 2020, as the Covid-19 pandemic spread through the state, Ms Sun allegedly found ways for Chinese consular officials to gain access to New York leaders.

So brazen were her efforts that, in one instance, she surreptitiously added a Chinese official to a private state government call about the public health response to the virus, according to prosecutors.

Former New York prosecutor Howard Master told the BBC the charges reflect a “disturbing” trend of senior public officials – including former New Jersey Senator Bob Menendez – corruptly receiving gifts from foreign governments.

“How she got away with it for so long will be a matter for ongoing investigation, but it appears that she took numerous steps to avoid getting caught, allegedly lying to the FBI, the New York State Office of the Inspector General, and others when questioned and taking other steps to conceal her role,” he said.

The indictment against Ms Sun lists occasions in which she worked to prevent Taiwanese representatives from either communicating with or meeting high-ranking officials in the US government.

“It’s all been taken care of satisfactorily,” Ms Sun is said to have bragged in one 2016 message to a Chinese consular official after successfully diverting a top New York politician from an event hosted by Taiwan.

And when the island’s president travelled to New York City in 2019, she was even pictured joining a pro-Beijing protest against the visit.

Up until January 2021, she worked behind the scenes to scrub mentions of Beijing’s detention of Uyghurs, a mostly Muslim ethnic group in Xinjiang Province.

When Chinese officials asked if the governor could record a Lunar New Year video, Ms Sun asked what “talking points” they wanted.

“Mostly holiday wishes and hope for friendship and co-operation,” the Chinese officials wrote. “Nothing too political.”

Ms Sun later told another Chinese official that she had argued with Ms Hochul’s speechwriter to get a mention of the “Uyghur situation” removed from a draft of the governor’s remarks.

In 2023, while working in the New York labour department, Ms Sun obtained a framed official Lunar New Year proclamation from Governor Kathy Hochul and presented it to a Chinese official.

The proclamation was produced outside of ordinary channels and even without the permission of Ms Hochul’s office.

Ms Sun also drafted fraudulent invitation letters for Chinese politicians to travel to the US and wrote an unauthorised letter of employment to add a compatriot to the New York governor’s Asian American advisory council.

In return, Ms Sun and Mr Hu “received substantial economic and other benefits from [Beijing] representatives”, prosecutors say.

The gifts included all-expenses-paid travel to China; tickets to top shows, concerts and sporting events; employment in China for Ms Sun’s cousin; and home deliveries of Nanjing-style salted ducks prepared by a Chinese government official’s personal chef.

According to the indictment, the duck delicacy was gifted to Ms Sun – and sent directly to her parents’ home – on at least 16 different occasions.

On Tuesday morning, federal agents entered the couple’s Long Island home and detained them on 10 criminal counts.

Her lawyer, Jarrod Schaeffer, was quoted by AP news agency as saying: “We’re looking forward to addressing these charges in court. Our client is understandably upset that these charges have been brought.”

A judge released the pair on bail, limiting their travel to three US states and ordering Ms Sun to avoid any contact with representatives from the Chinese consulate or mission in New York.