Donald Trump and his co-defendants have filed a motion seeking a mistrial on the grounds that the trial has been "tainted" by the appearance of bias on the part of Judge Arthur Engoron and his law.

"This appearance of bias threatens both Defendants' rights and the integrity of the judiciary as an institution," Trump's attorneys say in the filing. "As developed herein, in this case the evidence of apparent and actual bias is tangible and overwhelming."

"Specifically, the Court’s own conduct, coupled with the Principal Law Clerk, Allison Greenfield’s unprecedented role in the trial and extensive, public partisan activities, would cause even a casual observer to question the Court’s partiality," they write.

"Such evidence, coupled with an unprecedented departure from standard judicial procedure, has tainted these proceedings and a mistrial is warranted," the filing says.

Donald Trump's lawyers are scheduled to resume their direct examination of expert witness Jason Flemmons this morning, continuing a line of questioning yesterday that largely placed responsibility for Trump's financial statements on Trump's external accountants.

Flemmons, who was qualified as an expert on accounting, explicitly criticized the testimony of Donald Bender, Trump's accountant at Mazars USA who was the New York attorney general's first witness, disputing Bender's claim that he would have wanted to see any appraisals that the Trump Organization conducted.

Flemmons also testified that Trump's financial statements should have sent a "buyer beware" signal to lenders due to the "highly cautionary language" in their disclaimer, which allowed Trump to make claims that significantly departed from generally accepted accounting principles.

To the extent that the statements and the Trump Organization's representations about the statements were inaccurate, Flemmons placed responsibility on Bender and his colleagues at Mazars, rather than the Trump Organization.

Expert witness Jason Flemmons cast doubt on the testimony of the Trump Organization's former external accountant Donald Bender, who said he would have wanted to review any appraisals that the Trump Organization conducted.

"That's not something that is required by professional standards," said Flemmons, testifying for the defense. "His testimony was not professionally plausible."

That prompted a strong objection from state attorney Kevin Wallace.

"Is he trying to say the witness is lying?" Wallace said.

"Not to put too fine a point on it," Judge Engoron quipped.

Asked to confirm what he meant by "professional plausible," Flemmons said it would be "highly unusual" for Bender to request appraisals outside what was mentioned in the statement of financial condition.

"Accountants in the industry do not go seeking records for things that are not in the four corners of the statement of financial condition," Flemmons said.

Court was subsequently adjourned for the day, with Flemmons scheduled to continue his testimony tomorrow.

Defense expert Jason Flemmons described the disclaimer included in Donald Trump's financial statement as the "highest level disclaimer" that could have been provided to bankers reviewing the document.

Flemmons said that the disclaimer, which he said includes "highly cautionary language," would allow a user to make claims that significantly departed from generally accepted accounting principles, known in the industry as GAAP.

"Was that language present in a substantially similar form in the compilation statements issued by Mazars for Donald Trump?" defense attorney Jesus Suarez asked.

"Yes," Flemmons said, adding that the disclaimer was "effectively saying 'user beware.'"

During his testimony and in statements to the media, Trump has claimed that the disclaimer shields him from liability in the case.

Suarez also used Flemmons' testimony to suggest that Trump's external accountants were responsible for understanding the methods used in the financial statement and determining their appropriateness.

That appeared to conflict with testimony of former Trump accountant Donald Bender of Mazars USA, who described his role as akin to plugging numbers provided by the Trump Organization into a template.

Former President Trump appears to be done watching his civil fraud trial, and he had a lot to say about it on his way out of the courthouse.

Speaking to reporters, Trump renewed his attacks on Judge Engoron and accused the "whole system" of being rigged against him while referencing the criminal charges he faces in Washington, D.C., and Fulton County, Georgia.

"Our whole system is corrupt. This is corrupt. Atlanta is corrupt, and what's coming out of DC is corrupt," Trump said.

Trump again claimed that his net worth is more than is represented in his financial documents, and said that his Mar-a-Lago estate is worth "50 to 100 times more" than what Engoron determined.

Trump also resumed attacks on the judge -- who he said is "run by the Democrats" -- and New York Attorney General Letitia James, who he alleged is communicating with the Department of Justice to "keep me nice and busy."

The former president said he's been "stuck" in court when he would rather be campaigning in early primary states.

Asked by ABC News why he attended the trial despite no obligation to do so, he claimed his attendance was necessary to expose corruption to the press.

"Why attend? Because they want to point it out to the press how corrupt it is, because nobody else seems to be able to do it," Trump said.

Trump departed the courthouse and is not expected to return to court for the afternoon session.