Pierce Bainbridge Beck Price & Hecht and ex-partner Don Lewis have escalated their legal war against each other in recent days, with Lewis saying he has learned that key evidence against him is weaker than previously described and Pierce Bainbridge accusing Lewis of putting on a "litigation soap opera."

Pierce Bainbridge and Lewis filed dueling motions to dismiss suits they filed against one another in New York and California courts on Thursday and Friday. Lewis, in Friday's court filings, also sought sanctions against his former firm, claiming the suit against him was a public-relations stunt meant to blunt the impact of his own claims.

Pierce Bainbridge and its managing partner, John Pierce, have said Lewis was fired after he was "credibly accused" of sexually assaulting a staffer. Lewis has denied that and said he never got a copy of any supposed finding that his accuser was credible. In his court filings in Los Angeles, Lewis said he learned from Pierce Bainbridge partner Chris LaVigne that outside investigators at Putney Twombly Hall & Hirson, hired by his former firm, had "punted" and didn't make the rock-solid case against him that Pierce Bainbridge has suggested.

"Putney's own counsel has hinted that the report does not say what PB claims it says," Lewis said in a declaration. "This is consistent with [LaVigne's] comments to me that the Putney report is inconclusive and that nobody at the firm believes the false accuser."

LaVigne could not immediately comment.

Pierce Bainbridge is suing Lewis in Los Angeles Superior Court for allegedly attempting to extort the firm by filing a trumped-up lawsuit unless he was paid millions of dollars. Lewis says his allegations are true and supported by extensive evidence.

Back in Manhattan Supreme Court, Pierce Bainbridge and several of its lawyers filed papers Thursday seeking the dismissal of a lawsuit Lewis brought against them. That New York case accuses Pierce's firm, Putney Twombly, Littler Mendelson and several individual lawyers of defaming him, intentional infliction of emotional distress and violating §487 of New York's Judiciary Law, which bans attorney deceit.

Pierce Bainbridge, in its Thursday filings, said the statements Lewis claims are defamatory are privileged or protected as statements of opinion. The firm and its lawyers said the allegation that they engaged in deceit lacked any description of how Lewis was supposedly damaged and said the conduct at the core of the case—an investigation into sex misconduct claims—is "light years away" from what is needed for an emotional-distress claim to survive a motion to dismiss.

Lewis and his lawyer, Neal Brickman, expressed confidence in their case in statements to ALM on Monday. They have said documents from a largely sealed case Pierce Bainbridge filed in an effort to make Lewis file his own allegations under seal make clear that the firm's lawyers have lied.

"In their effort to demonize Mr. Lewis and improperly destroy his reputation and career, Pierce Bainbridge cannot keep track of their own lies," Brickman said in a statement. "They argue one thing in New York and allege the complete opposite in Los Angeles. Unfortunately for them, we have contemporaneous e-mails, texts and Slack messages that definitively show that they have lied to the courts on both coasts."

Asked for comment, Pierce Bainbridge's lawyer Marc Mukasey of Mukasey, Frenchman & Sklaroff referred to a passage from the firm's dismissal motion in New York.

"This case continues the vainglorious litigation soap opera produced and directed by plaintiff Donald Lewis," Mukasey wrote in an email to ALM, quoting the firm's filings. "Lewis has turned a basic employment case into a vexatious clutter of far-fetched and incomprehensible allegations spread over two convoluted lawsuits filed in this court. Lewis was fired not because of his threats to make false claims of financial impropriety at the firm, but because of his own misconduct."

The parties are expected to be in court later this month for dismissal arguments in a related suit that Lewis brought against his former partners.