NEW YORK (AP) — The judge in Donald Trump's civil fraud trial is demanding more information after a key witness was reported to be in negotiations to plead guilty to perjury in connection with his testimony in the lawsuit.

In an email posted to the trial docket Tuesday, Judge Arthur Engoron asked lawyers in the case to provide him with a letter "detailing anything you know" about the situation involving Allen Weisselberg, the former longtime finance chief at Trump's company, the Trump Organization.

"I do not want to ignore anything in a case of this magnitude," Engoron wrote, suggesting he may disregard all of Weisselberg's testimony if he were to admit to lying on the witness stand.

Engoron cited a Feb. 1 report in The New York Times that Weisselberg was in negotiations with the Manhattan district attorney's office to plead guilty to perjury and "admit that he lied on the witness stand" when he testified at the civil fraud trial in October. The newspaper cited "people with knowledge of the matter."

The Associated Press, citing two people familiar with the matter who spoke on the condition of anonymity, reported that Manhattan prosecutors were weighing a potential perjury charge against Weisselberg.

"As the presiding magistrate, the trier of fact, and the judge of credibility, I of course want to know whether Mr. Weisselberg is now changing his tune, and whether he is admitting he lied under oath in my courtroom at this trial," Engoron wrote in the email.

Engoron's email went to lawyers for Trump, Weisselberg, the Trump Organization and other defendants, as well as counsel for the New York Attorney General Letitia James' office, which brought the civil fraud case.

Messages seeking comment were left with Trump and Weisselberg's lawyers, as well as with spokespeople for the Trump Organization. The Manhattan district attorney's office and the attorney general's office both declined to comment.

Engoron asked the lawyers to respond by 5 p.m. Wednesday, adding that he wanted their thoughts on how he should address the matter, including timing of his final decision in the case, which court officials have said should be ready by mid-February.

Weisselberg was one of 40 witnesses who testified over 2½ months at the civil fraud trial, answering questions for two days about allegations that Trump lied about his wealth on financial statements given to banks and insurance companies.

It wasn't clear what part of Weisselberg's testimony drew the scrutiny of prosecutors in the office of Manhattan District Attorney Alvin Bragg. Both Bragg and James are Democrats.

The Times reported that prosecutors appeared to be focused on Weisselberg's claims on the witness stand on Oct. 10 that he had little knowledge or awareness of how Trump's penthouse at Trump Tower came to be overvalued on his financial statements based on figures listing it as three times its actual size, 10,996 square feet (1,022 square meters).

Weisselberg testified that he didn't pay much mind to the apartment's size because its value amounted to a fraction of Trump's wealth.

"I never even thought about the apartment. It was de minimis, in my mind," Weisselberg said, using a Latin term that means, essentially, too small to care about. "It was not something that was that important to me when looking at a $6 billion, $5 billion net worth," Weisselberg added.

Weisselberg said he learned of the Trump Tower penthouse size discrepancy only when a Forbes magazine reporter pointed it out to him in 2016. He testified that he initially disputed the magazine's findings but said he couldn't recall whether he directed anyone to look into the matter.

"You don't recall if you did anything to confirm who was right?" state lawyer Louis Solomon asked.

Weisselberg said he did not.

He was still on the witness stand when Forbes, whose reporters had discussed the size disparity with Weisselberg and revealed it publicly in 2017, published an article on its website suggesting he had perjured himself.

"Trump's Longtime CFO Lied, Under Oath, About Trump Tower Penthouse," the article's headline said. It said old emails and notes showed that Weisselberg had had extensive discussions with the magazine, trying to convince its writers that the penthouse was worth far more than they thought.

In addition to being a witness, Weisselberg is a defendant in James' civil lawsuit. As punishment for his involvement in Trump's alleged fraud, James is seeking to permanently ban the retired ex-CFO from the real estate industry and corporate executive jobs in New York and strip him of his $2 million Trump Organization severance.

Weisselberg served 100 days in jail last year for dodging taxes on $1.7 million in perks from the Trump Organization, including a Manhattan apartment, Mercedes-Benz cars for him and his wife, and his grandchildren's school tuition.

Under a plea deal in that case, Weisselberg testified as a prosecution witness at the 2022 trial that resulted in the Trump Organization tax fraud conviction in connection with the same off-the-books compensation scheme. He is still on probation. Trump is paying his severance in installments and covering the cost of his legal bills.

A new charge could put Weisselberg, 76, behind bars again.

The inquiry into Weisselberg's testimony in the civil lawsuit is separate from the criminal case that Bragg brought against Trump last year over allegations that he falsified company records to cover up hush money payments. That trial is scheduled to begin in late March.