A former NYPD sergeant was convicted Tuesday of acting as a Chinese agent in a scheme called “Operation Fox Hunt” that sought to force people living abroad to return to China.

Michael McMahon — a cop-turned-private eye — was convicted by a Brooklyn federal jury Tuesday on three of the four charges he faced for acting as an agent of China when he stalked and coerced former Chinese official and New Jersey resident Xu Jin in a bid to get him to return to his home country to face bribery and embezzlement charges.

McMahon, 55, of Mahwah, NJ, was convicted of illegally acting as an agent of a foreign government, stalking, and conspiracy to engage in interstate stalking and faces up to 20 years behind bars at his sentencing.

He was acquitted on one count of conspiracy to act as an agent of a foreign government.

At trial, McMahon’s lawyer Lawrence Lustberg, argued that his client didn’t know that when he took the private surveillance job that he was working as an agent of Beijing.

“He certainly didn’t know he was involved in a campaign called Fox Hunt or Skynet that involved transnational repression,” Lustberg said, during opening statements at the end of May.

But federal prosecutor Irisa Chen argued McMahon knew what he was getting into but simply “looked the other way.”

McMahon — whose soap opera actress wife Martha Byrne appeared on “As the World Turns” from 1985 to 2009 — was charged in 2020 alongside Congying Zheng and Yong Zhu in a scheme that took place from 2016 through 2019 in an attempt to pressure Xu and his wife to return to China.

Prosecutors claimed that the trio sent strangers to Xu’s sister-in-law’s home to relay a threatening message, left a chilling note on his door and even sent his father to the US “as bait.”

McMahon’s role included researching information about Xu and his wife which he got from law enforcement and government databases and then feeding the information back to a Chinese police officer and others. He also spied on Xu’s sister outside of her New Jersey home and reported his findings to Chinese agents.

Zhu was convicted of all counts and faces up to 25 years at his sentencing.

Zheng was only convicted of interstate stalking and conspiracy to commit interstate stalking for leaving a threatening note on Xu’s door in 2018. He faces up to 10 years in prison.

“If you are willing to go back to the mainland and spend 10 years in prison, your wife and children will be safe,” said the ominous note left by Zheng.

Zheng Conying was convicted on the stalking and stalking conspiracy counts and acquitted of the other two counts

“The jury’s verdict confirms that defendants McMahon and Zhu knowingly acted at the direction of a hostile foreign state to harass, intimidate and attempt to cause the involuntary return of a resident of the New York metropolitan area to the People’s Republic of China, and that defendant Zheng harassed and intimidated that same person and his family,” Brooklyn US Attorney Breon Peace said in a statement.

“It is particularly troubling that defendant Michael McMahon, a former sergeant in the New York City Police Department, engaged in surveillance, harassment, and stalking on behalf of a foreign power for money,” Peace said.

Other coercive measures used against Xu included having his elderly father, Cewei Xu, sent to the US in 2017 with a flip phone and instructions on how Zu should fill out paperwork at the airport to show the Chinese meant business, prosecutors said.

McMahon also once followed Xu to his home following the meeting with his father and sent the address to Chinese operatives — who didn’t previously know where he lived, prosecutors said.

And Xu’s sister in law, Liu Yan, testified at trial about how two strangers came to her Short Hills, NJ home on Thanksgiving in 2016 giving her a message to relay to Xu.

“If you don’t go back to China, you and your family will be in trouble,” Liu was told to tell Xu. “If you want to resolve this issue, there’s only two ways: either you go back to China on your own and admit the crime or you disappear.”

Liu also claimed that she got an unexpected drop-in from Xu’s dad telling her he was on a mission to convince his son to repatriate back home. And a few days later, Liu claimed she thought she was being followed.

Xu — who has been in the US for 13 years — headed the municipal development division in Wuhan before the Chinese Communist Party turned on him and he was accused of taking millions of dollars in bribes, according to a 2021 ProPublica report.

The Chinese government put out an international notice for his arrest.

Three other defendants in the case previously pleaded guilty while two remain at large and are believed to be in China.

Lustberg told The Post the verdict was a “terrible injustice” and vowed to fight it including ultimately appealing “if necessary.”

“We are obviously very disappointed with today’s verdict and feel strongly that it is not consistent with the evidence in the case but more importantly, is not consistent with the truth,” Lustberg said. 

“That truth is that Michael McMahon never had any idea that he was working for the Chinese Government,” Lustberg said. “If he had, he would not have taken the job or done the work he did.”

Zhu’s lawyer, Kevin Tung, said the defendants “should not be held liable for the charges.”

“It is still my strong belief that the defendants were used by the foreign government to work for them,” Tung said, adding that they didn’t knowingly work as Chinese agents.

Zheng’s lawyer Renee Wong said they “are pleased the jury was able to see that Mr. Zheng’s brief and limited involvement had no connection to the Chinese Government.”

“We are disappointed in the stalking verdict,” Wong said. “Mr. Zheng’s one-time conduct of knocking on the door and leaving a note for the Chinese fugitive victims, definitely does not align with the common sense definition of stalking.”

Wong added that her client believed no one was home when he left the note and “in an act of maturity” returned to the house the next day to try to remove it. The lawyer didn’t say if she would appeal.

A lawyer for Zhu didn’t immediately return a request for comment Tuesday.