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.

State attorney Kevin Wallace concluded his direct examination of the New York attorney general's second and final rebuttal witness amid frequent objections by defense lawyers.

Lewis attempted to explain how Donald Trump's statements of financial condition failed to disclose that he did not conduct a discounted cash flow analysis, contributing to the over-valuation of some of his assets.

"There is no mention of discounting or future value in the disclosure," Lewis said, disagreeing with testimony from defense expert Jason Flemmons -- as well as former Mazars USA accountant Donald Bender, who testified as a state witness.

“Are you impeaching your own witness?” Engoron asked state attorneys regarding whether Bender’s testimony should no longer be considered credible.

"We didn't feel the need to," Wallace responded.

Lewis also suggested that Trump's external accountants at Mazars had less of an obligation to highlight issues that Flemmons suggested, since they were only conducting a compilation report rather than a more intensive audit. While Mazars had an obligation to flag obvious issues, they were not responsible for ensuring Trump's statements were compliant with generally accepted accounting principles, he testified.

"If while doing the compilation ... something comes to the attention of the accounts that could be a GAAP departure, they have a responsibility to bring that issue to the client," Lewis said regarding generally accepted accounting principles.

During the hour-long direct examination, defense lawyers objected at least 14 times, successfully interrupting the line of questions.

"I am lost," Engoron asked at one point. "Can you put this together?"

The parade of objections visibly irritating Wallace, who voiced his displeasure.

"Petulant outbursts don't really play well in the courtroom," quipped Trump lawyer Chris Kise in response.