A Long Island doctor claims a nearly $1.5 million house is being built on the vacant Connecticut lot that’s been in his family for 70 years without his knowledge because of a stunning fraud scheme, according to a federal lawsuit.

Dr. Daniel Kenigsberg’s jaw dropped when he swung by what used to be his empty lot in Fairfield, Connecticut — only to find a partially constructed three-story house on the property.

The pricey home, which boasts four bedrooms and four full bathrooms, has transformed a parcel previously covered in trees into a now-stalled construction project.

“I was living my life normally until May 31st,” Kenigsberg told the Washington Post, “and all of a sudden, this happened.”

The property was fraudulently transferred to Sky Top Partners LLC for $350,000 in October 2022, according to the federal lawsuit obtained by The Post.

While the transfer title claims Kenigsberg signed off on the move in Johannesburg, South Africa, the lawsuit argues his signature was forged and he was impersonated.

“Dr. Kenigsberg has never lived in Johannesburg, South Africa and was not traveling there in 2022,” the lawsuit states. “Dr. Kenigsburg never authorized the sale of his property to anyone.”

Sky Top Partners and Anthony Monelli, the lawyer who helped complete the deal, are the listed defendants.

Kenigsberg, who lives in East Setauket, first got an inkling something was wrong at the property when he was talking to a childhood friend, who still lives in Fairfield and mentioned they were building on the land, CT Insider reported.

“They’re doing what? I said, ‘I own that and I never sold it,’” Kenigsberg told the outlet. “I was shocked.”

He stopped by that same day for the first time in five years to see for himself, the Washington Post reported. That’s when he saw the under-construction house that was listed for $1,475,000 in August 2022.

The property has been in Kenigsberg’s family since 1953, when his father purchased it, and he obtained the deed to it after his mother died in 2007, the Washington Post reported.

He grew up next to the lot in a house that he later sold in 2011.

While the defendants are reportedly not accused of being behind the wild scheme, the lawsuit claims they knew or should have known the transfer was a forgery, the lawsuit states.

“It looks like somebody from South Africa reached out to maybe the broker and maybe Attorney Monelli,” Kenigsberg’s lawyer Peter Nolin told CT Insider, later stating. “Apparently there are scammers around the country doing this kind of thing.”

Police said a criminal probe is underway as investigators are trying to determine who received money from the buyers, the outlet reported.

The lawsuit ultimately demands the deed transfer be tossed, but in the meantime, any work on the house must be stopped as the case makes its way through the justice system, according to legal papers.

“I’m angry that so many people were so negligent that this could have happened. … It wasn’t for sale … It’s more than obnoxious, it’s offensive and wrong,” Kenigsberg told CT Insider.