President Donald Trump's niece, Mary L. Trump, on Thursday filed a lawsuit in State Supreme Court in Manhattan against President Trump and his siblings, claiming the family defrauded her out of millions of dollars in inheritance.

The suit seeks unspecified monetary damages against Donald Trump, his sister Maryanne Trump Barry and the estate of the late Robert Trump, who died in August with an estate valued at $50 million. The suit alleges fraud, conspiracy and violations of fiduciary duties.

"Rather than protect Mary’s interests, they designed and carried out a complex scheme to siphon funds away from her interests, conceal their grift, and deceive her about the true value of what she had inherited," the lawsuit reads.

The suit also notes: "For Donald J. Trump, his sister Maryanne, and their late brother Robert, fraud was not just the family business — it was a way of life."

Mary's book, "Too Much And Never Enough," outlined how President Trump and his siblings constantly cheated on their taxes, swindled business partners, and raised rent for low-income tenants while also lying about the inheritance Mary was to receive.

The suit alleges that when her grandfather, Fred Trump Sr., died in 1999, Donald Trump and his siblings tried to squeeze Mary out of the will. Mary argues that her aunt and uncles threatened to bankrupt her and cut her off from health insurance.

As part of a 2001 settlement over Fred Trump Sr.'s will, the president and his siblings were accused of giving Mary false estimates of what Fred Trump Sr. was worth. 

The suit also notes that Mary was forced to sign the settlement. 

Mary learned from a New York Times investigation that the family estate included in the settlement was worth close to $1 billion instead of the $30 million she was told. 

White House press secretary Kayleigh McEnany dismissed the allegations when asked about them at a press briefing and said Mary "really discredited herself."

"The only fraud committed there was Mary Trump recording one of her relatives," McEnany said, a reference to secretly recorded conversations between Mary Trump and her aunt Maryanne Trump Barry, who called Donald Trump "a liar."