Paul Ceglia, the Buffalo, N.Y., man who claims to own half of Facebook, is—if nothing else—a tenacious litigant. Facebook’s lawyers at Gibson, Dunn & Crutcher have uncovered evidence that the purported contract in Ceglia’s ownership case is fake, up to nine sets of lawyers have quit his case, a federal grand jury indicted him on charges of wire and mail fraud related to the allegedly fabricated contract, and still he presses on. Ceglia’s latest gambit is the lawsuit he filed in March against Attorney General Eric Holder, accusing Holder and a trio of federal prosecutors in New York of violating the Constitution in their criminal case against him.

The Justice Department, for its part, is not impressed.

On Friday the DOJ filed a motion to dismiss Ceglia’s suit in U.S. District Court in Buffalo, calling his claims “frivolous” and “confusing.” To fight the criminal case, Ceglia shouldn’t have filed a separate action to enjoin it, he should have simply moved to dismiss it, the motion says. “Plaintiff here has an adequate remedy at law; he is indicted, he may raise all of his constitutional challenges by seeking to have the indictment dismissed,” the government argues.

The DOJ also says the First Amendment claim in Ceglia’s March lawsuit makes little sense. “Plaintiff is not being prosecuted in the Southern District of New York because he filed a lawsuit; he is charged with mail and wire frail because he is alleged to have doctored and fabricated evidence before (and after) filing the suit,” the brief says. “The First Amendment does not protect such fraudulent conduct.”

San Francisco plaintiffs lawyer Joseph Alioto of the Alioto Law Firm, who signed on to represent Ceglia in April, did not immediately respond to a request for comment.

Ceglia first claimed to own half of Facebook in a June 2010 lawsuit against the social network and its founder Mark Zuckerberg. Ceglia claims that Zuckerberg agreed to give him the ownership stake in lieu of payment for some minor programming services. In August 2011, Facebook’s lawyers at Gibson Dunn said they found “smoking gun” evidence that disproved the authenticity of the purported contract at the heart of Ceglia’s case.

In late March—two weeks after Ceglia sued his criminal prosecutors—a federal magistrate judge in Buffalo determined that the evidence Gibson Dunn had turned up was convincing and recommended the dismissal of Ceglia’s ownership case. U.S. District Judge Richard Arcara has not yet acted on that advice.