The legal team of former Fox News host Tucker Carlson on Tuesday sent the network, which abruptly took his shows off the air last month, a scathing letter accusing it of fraud and contract violations that could merit litigation.

The document challenges the noncompete provision of Carlson’s contract, which if nullified could allow the star to develop a new show or media project independent of Fox, Axios first reported. Written by attorney Bryan Freedman and addressed to Fox officials Viet Dinh and Irena Briganti, the letter claimed that Fox breached its contract with Carlson, therefore making it excusable for him to start a new media venture. Freedman alleged that Fox staff, including “Rupert Murdoch himself,” reneged on commitments to Carlson “intentionally and with reckless disregard for the truth” that amounted to fraud, Axios said.

Fox violated a promise made to Carlson, the letter said, not to leak his private messages to the press or use them “to take any adverse employment action against him,” the outlet added.

During the discovery process in the case between Dominion Voting Systems and Fox, some of Carlson’s texts were unearthed, revealing disparaging comments he made about the company’s management. In other messages, Carlson blasted former president Trump, saying “I hate him passionately.” Some outlets have speculated that Carlson’s attacks on Fox’s leadership in those communications contributed to his ouster.

The letter argues that Fox broke an agreement not to settle the lawsuit with Dominion “in a way which would indicate wrongdoing” by Carlson in the drama. Two sources told Axios that a member of the Fox board told Carlson that his job was axed as a condition of the Dominion settlement.

Also on Tuesday, Carlson announced he would be producing content on Twitter going forward, suggesting a new collaboration of sorts with new CEO Elon Musk, who has promised to protect free speech on the social-media platform. Sources told Axios that Carlson’s lawyers sent the letter to Fox before the pundit unveiled his Twitter series.

“Starting soon we’ll be bringing a new version of the show we’ve been doing for the last six and a half years to Twitter,” Carlson said in a video monologue reminiscent of those he used to broadcast in the 8 p.m. prime-time slot for Fox. “We bring some other things too, which we’ll tell you about. But for now we’re just grateful to be here. Free speech is the main right that you have. Without it, you have no others.”

Multiple conservative media companies and personalities, from Glenn Beck at the Blaze to Jeremy Boering at the Daily Wire, have made offers to Carlson. For now, it appears the commentator will have a presence on Twitter, presumably with the blessing of Musk.