Former US President Donald Trump is suing his niece and the New York Times over a 2018 article that alleged he was involved in "dubious tax schemes", APA reports citing BBC.
The lawsuit, filed in New York, accuses Mary Trump and newspaper reporters of being "engaged in an insidious plot" to obtain confidential documents.
It alleges that Ms Trump, 56, breached a settlement agreement barring her from disclosing the documents.
She revealed herself as the source of the story in a tell-all memoir in 2020.
Ms Trump, the daughter of Fred Trump Jr, the president's older brother who died in 1981 at the age of 42, has not yet commented on the lawsuit.
Mr Trump has consistently rejected the claims made in his niece's book - Too Much and Never Enough: How My Family Created the World's Most Dangerous Man - and unsuccessfully sued to try to block its publication.
On Tuesday, a lawsuit filed in a state court accused New York Times journalists Susanne Craig, David Barstow and Russell Buettner of contacting and working with Mr Trump's niece as part of a "personal vendetta" against him.
"A group of journalists with the New York Times, in the middle of an extensive crusade to obtain Donald J Trump's confidential tax records, relentlessly sought out his niece Mary... and convinced her to smuggle the records out of her attorney's office," the lawsuit reads.
It alleges that Mr Trump "suffered significant damages" and states that he is seeking compensation of no less than $100m (£73m).