Donald Trump has filed suit against a former senior campaign aide, alleging a breach in a confidentiality agreement.

Trump seeks $10 million in damages from former senior campaign consultant Sam Nunberg, the top aide who was fired last summer.

In a court filing obtained by The Associated Press, Nunberg accuses Trump of trying to silence him “in a misguided attempt to cover up media coverage of an apparent affair” between campaign spokeswoman Hope Hicks and former campaign manager Corey Lewandowski.

The filing cites a May 2015 New York Post story detailing a public “screaming match” between the pair, quoting several sources to describe the campaign’s “internal discord.”

It is unclear what role Nunberg played in the Post’s story and how, exactly, he allegedly violated the terms of his confidentiality agreement. But as The Daily Beast reported this year, “the threat of legal action has not stopped Nunberg from speaking his mind about Trump since he was fired from the campaign in August. In December 2015, Nunberg told The Daily Beast, ‘I do not think that he will win.’ Also in 2015, Trump mailed Nunberg a cease and desist notice.”

And when Nunberg began publicly discussing the campaign’s prospects, Trump told The Daily Beast: “[Nunberg] is a highly self-destructive individual who makes routine calls begging for his job back. This is the interview of a desperate person who is trying to hang on and stay relevant.”

The lawsuit reflects Trump’s infamous litigiousness. As The Daily Beast documented last year, the real-estate mogul has sued or threatened to sue news outlets, from Univision to The New York Times; businesses, from a Georgia-based business card store to casinos and TV broadcasters; places like New York City, the town of Palm Beach, and Scotland; and individual people, from his ex-wife Ivana Trump to his own hairdresser to rapper Mac Miller.

The presumptive Republican presidential nominee sought to litigate the case in private, but the court documents were revealed when Nunberg filed Monday for a stay in the arbitration.