Donald Trump filed a lawsuit in federal court on Wednesday against his former lawyer Michael Cohen — who has emerged as a key witness in the criminal case against the former president — seeking more than $500 million in damages for alleged “breaches of fiduciary duty, unjust enrichment, conversion, and breaches of contract.”

Cohen was the key witness to testify last month before a Manhattan grand jury, which then approved a 34-count indictment against Trump. The former president has denied any wrongdoing.

The complaint accuses Cohen of violating his attorney-client relationship with Trump by publicly disclosing information about the former president and “spreading falsehoods about [Trump], likely to be embarrassing or detrimental, and partook in other misconduct in violation of New York Rules of Professional Conduct.”

The former president has “suffered vast reputational harm as a direct result of Defendant’s breaches,” Trump’s lawyer Alejandro Brito wrote in the complaint filed in U.S. District Court for the Southern District of Florida.

Trump’s attorney said that Cohen did those things with “malicious intent and to wholly self-serving ends.”

“Defendant has engaged in such wrongful conduct over a period of time and, despite being demanded in writing to cease and desist such unacceptable actions, has instead in recent months increased the frequency and hostility of the illicit acts toward Plaintiff,” Trump’s lawyer wrote.

Cohen’s attorney, Lanny J. Davis, responded to the lawsuit by saying Trump “appears once again to be using and abusing the judicial system as a form of harassment and intimidation.”

“It appears he is terrified by his looming legal perils and is attempting to send a message to other potential witnesses who are cooperating with prosecutors against him,” Davis said in a statement. “Mr. Cohen will not be deterred and is confident that the suit will fail based on the facts and the law.”

Trump wants “compensatory, incidental, and punitive damages” in an amount that would be determined at a trial and would “substantially exceed” $500 million, the complaint said. He also wants any profits or compensation Cohen receives from his books, podcast or other products.

The lawsuit tried to thread a difficult thread — arguing that Cohen violated the attorney-client relationship by revealing confidential information but also that Cohen has repeatedly lied. And while the filing attacks Cohen as dishonest, it noted that he has also made many positive statements about Trump such as, “Defendant viewed Plaintiff as a ‘wonderful man’ who would be ‘an amazing president.'”

Trump has railed against Cohen, the former president’s previous longtime attorney, who pleaded guilty in 2018 to a host of charges tied to tax evasion, as well as lying to Congress in its investigation into Russian interference in the 2016 election and his role in funneling payments to silence two women who alleged that they had affairs with Trump.

Cohen completed his resulting prison sentence in November 2021. Trump has denied the affairs and any wrongdoing connected to the hush money payments.

Last week, the former president pleaded not guilty to 34 felony counts of falsifying business records related to his role in those hush money payments toward the end of his 2016 presidential campaign.

Trump’s lawsuit offers his own case about the payment to adult film star Stormy Daniels ahead of the 2016 — seeming to argue that Cohen didn’t disclose the payments to a different Trump lawyer, Robert Costello, until February 2018.

In the suit, Trump cites news articles about Costello’s testimony before the grand jury to say that Cohen told Costello that he had “negotiated a nondisclosure agreement for $130,000,” and expressly stated that the $130,000 payment did not come from” Trump.

In May 2018, Trump filed an amended financial disclosure that acknowledged the payments to reimburse Cohen and that those payments were made in 2017.

The statement of facts filed by prosecutors in the Manhattan case detailed how Cohen oversaw hush money payments to three people: Daniels, Playboy model Karen McDougal and a former Trump Tower doorman who’d claimed to have a story about a child Trump had out of wedlock.

This article was originally published on NBCNews.com