President Donald Trump’s recently dismissed $10 billion lawsuit against the Internal Revenue Service should be reopened so the judge who oversaw it can investigate “whether a fraud occurred,” 35 former federal judges argued Wednesday.

Trump, his two eldest sons and the Trump Organization on May 18 abruptly dropped their case against the IRS and the Treasury Department, which was based on leaks of their tax information by an ex-IRS employee in 2019 and 2020.

Federal Judge Kathleen Williams of Miami District Court accordingly ordered the case dismissed with prejudice, while noting that the move cancels an upcoming deadline related to her efforts to scrutinize the matter.

She also noted in her ruling that the plaintiffs made no reference to a settlement and that the defendants did not submit any settlement documents.

The same day, the Department of Justice announced that as part of a settlement agreement in the case, the U.S. attorney general will establish a $1.776 billion “Anti-Weaponization Fund.”

One day later, the DOJ revealed an addendum to the settlement that effectively shielded the plaintiffs and certain affiliates from any IRS enforcement regarding their past tax returns.

“The Court was deceived,” the ex-judges wrote in a court filing Wednesday afternoon.

“Despite Plaintiffs not having mentioned any settlement in their Notice, the [DOJ] publicly announced a ‘settlement’ of this action shortly after Plaintiffs filed their dismissal,” they wrote.

That settlement “raises profound questions about the parties’ candor toward the Court and manipulation of the judicial system, which threatens to undermine confidence in the administration of justice,” they argued.

Among the retired judges who joined the filing is J. Michael Luttig, who had testified before the House select committee investigating the Jan. 6, 2021, Capitol riot.

The ex-judges seek to “raise a challenge of fraud” through Rule 60 of the Federal Rules of Civil Procedure, which they say allows Williams to reopen the case. As an alternative, they urged Williams to reopen the proceeding on her own.

In either case, they want the court to “set aside the judgment in this lawsuit,” allowing it to “resume its inquiry into whether there is an actual underlying case or controversy, or whether, to the contrary, this ‘case’ that the parties purport to have ‘settled’ is itself a fraud on the Court.”

The judges asserted that the settlement is a “product of collusion and is itself a fraud on the Court.” But Williams does not need to immediately agree in order to set aside her dismissal, they argued.

Reopening the case “will allow the Court to commence an inquiry into whether the Court was deceived, including with respect to the existence of an underlying case or controversy and any purported arms-length negotiations undertaken to resolve it.”

The White House referred CNBC to the Department of Justice, which did not immediately respond to a request for comment on the filing. The IRS and the Trump Organization did not immediately comment on the filing.