Brooklyn federal prosecutors charged two former Chinese diplomats Tuesday with a forced labor scheme in which workers brought from China under special visas to work at diplomatic facilities were instead deployed to private construction projects including a dwelling in Old Brookville.

The government said the workers were forced to work or risk losing their homes in China and face unspecified “political” repercussions. So-called “escapees” were tracked down and projects in Old Brookville and elsewhere weren’t licensed by local authorities, officials said.

The description of the Long Island residence appeared to match a $10 million mansion in Old Brookville that has figured in two other recent cases involving China, adding more mystery to an investigation that has involved suggestions of spying and diplomatic intrigue.

Chinese billionaire Ng Lap Seng, now facing federal charges of bribing UN diplomats in Manhattan, allegedly visited the house just before his arrest last year. The government questioned him about intelligence ties of its owner, a Chinese man named Qin Fei, and has charged a former China Air agent from Queens with obstruction of justice for helping the owner flee the U.S.

The case, unsealed Tuesday, charged Dan Zhong and Landong Wang with carrying out the illegal labor scheme as the “principal” and manager of U.S. operations for an unnamed Chinese construction company that brought in workers under special A2 and G2 visas to work on People’s Republic of China facilities.

Zhong, 46, was detained Saturday and has a bail hearing in Brooklyn federal court scheduled for Thursday, according to court records. His lawyer did not return an email request for comment. Wang’s whereabouts is unknown. A spokesman for Brooklyn U.S. Attorney Robert Capers said he was a fugitive.

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“Multiple” escapees allegedly said they were threatened with the loss of large cash deposits as well as their homes in China if they didn’t stay and work or tried to run away, and were forced to sign “debt bondage contracts.”

They were paid $1,180 a month, according to the complaint, but had to leave $22,000 on deposit and were housed together in packed dwellings in Jersey City. The contract said that if the workers ran away or violated other terms, the company “will no longer assume responsibility for . . . personal or political safety.”

Violations could include words or deeds “detrimental” to the “national prestige” of the company, or a “secretly liaison with overseas connections,” said the complaint, filed by an agent of the Department of Homeland Security.

The government said the scheme had been operating since 2010, and during a 2015 FBI surveillance of the house in Old Brookville several workers linked to the company were spotted working on renovations that documents indicated were to cost more than $1.2 million.

A proposal for the work, obtained by the government, contained the provision, “No filing with the local department of buildings, No permits, No insurance or bond, No licensed plumbing and electrical trades will be used.”

The complaint indicated that as many as 46 Chinese workers may have been in the U.S. as part of the scheme. One house in Jersey City, raided in 2011, housed 28, and some were in the U.S. as long as four years.

In addition to the Old Brookville mansion, the complaint said the construction company did work on a Queens house whose owner appeared to fit the description of the China Air agent previously charged, and a 5th Avenue high-rise that is under construction.

The complaint said that last fall, after agents questioned Wang, a half-dozen workers were booked on flights back to China. After questioning, they were served with grand jury subpoenas. They left for China the next day and have not returned, the government said.