The People of the State of New York v. Donald J. Trump, et al, is scheduled to get underway in lower Manhattan at 10 a.m. with opening statements.

If opening statements are completed before the end of the day, the New York attorney general plans to begin her case by calling Trump's former Mazars USA accountant Donald Bender to the stand.

Mazars severed its business relationship with the former president last year after learning of the attorney general's findings during the AG's probe.

Though Trump has denied all wrongdoing alleged by the attorney general, Judge Arthur Engoron has already decided the central allegation against Trump and his co-defendants, ruling in a pretrial hearing last week that the AG had provided "conclusive evidence" that Trump overvalued his assets between $812 million and $2.2 billion.

The judge then canceled the Trump Organization's business certificates in New York, severely restricting Trump's ability to conduct business in the state moving forward -- a move that Trump attorney Alina Habba called "nonsensical" and "outrageously overreaching."

"In defendants' world: rent regulated apartments are worth the same as unregulated apartments; restricted land is worth the same as unrestricted land; restrictions can evaporate into thin air," Engoron wrote, citing multiple arguments made by defense to justify the allegedly inflated valuations of Trump's assets. "That is a fantasy world, not the real world."

Among the issues still to be determined at trial: What additional penalties Trump might face, and what might happen with the multiple causes of action included in the attorney general's suit.

Former President Donald Trump stepped up his attacks on the judge overseeing and deciding his case, writing on Truth Social overnight that Justice Arthur Engoron should resign and be sanctioned for "abuse of power."

Similar to an earlier post, Trump criticized allegations regarding the value of his Mar-a-Lago estate, in addition to an appellate court's ruling that his lawyers unsuccessfully tried to use to limit the timeframe of the case.

Former President Trump posted on his Truth Social platform Sunday night that he intends to attend the opening of the trial.

"See you in court -- Monday morning," he wrote in a post.

Earlier Sunday, multiple sources familiar with the decision told ABC News that Trump was expecting to attend.

Trump will have no speaking role in court on Monday, but it is anticipated that he'll return to the courthouse toward the end of the state's case when court records show he will be called as a witness.

Day 13 of the trial is scheduled to get underway this morning with continued testimony from Ladder Capital executive Jack Weisselberg, who took the stand yesterday afternoon.

The son of former Trump Organization CFO Allen Weisselberg, who is a defendant in the case, Jack Weisselberg said yesterday that he often worked directly with his father while working on a 2015 deal to refinance the Trump Organization's $160 million mortgage of its 40 Wall Street office building.

The younger Weisselberg also described interactions with the Trump Organization executives who worked to protect the sensitivity of Trump's financial information.

"I think they were concerned about confidentiality and wanted to make sure it got into my hands," said Jack Weisselberg, describing how Trump's financial documents were sent to him via a messenger.

He also testified how, when Trump Organization executives were contemplating a 2012 loan, they appeared sensitive about making certain financial documents public -- including how much fashion brand Gucci paid in rent at Trump Tower.

"He is also nervous about Gucci's rent becoming public knowledge, as he tends to embellish from time to time," Jack Weisselberg wrote in a 2012 email that was entered into evidence, apparently referring to Trump.

"I recall it being public was a concern," Jack Weisselberg said when asked about the information referenced in the email.