The Trump Organization’s trusted outside accounting firm has taken the unprecedented step of ditching its client, explaining that the former president’s family company has a decade of financial statements that can’t be trusted.

The bombshell move by Mazars USA—the accounting firm that has long worked with former President Donald Trump’s family and friends—was revealed in court filings in New York on Monday.

The decision to drop Trump follows last month’s aggressive move by New York Attorney General Letitia James to publicly file documents detailing accounts of what it called “significant evidence” of financial fraud.

The AG’s office is in the midst of two similar investigations of the Trump empire: A civil lawsuit exploring potential bank fraud by the company, and a joint criminal probe with the Manhattan District Attorney into alleged tax dodging and financial fraud.

While the criminal case is proceeding quietly before a grand jury in New York City, Monday’s revelations stem from the AG’s civil lawsuit, which seeks to force Trump and two of his adult children to testify about business dealings.

In a letter to the Trump Organization on Feb. 9, the U.S. branch of the global accounting firm Mazars told the company that “the statements of financial condition for Donald J. Trump” ranging between 2011 and 2020 “should no longer be relied upon and you should inform any recipients thereof… that those documents should not be relied upon.” The firm explained that the decision was made in light of the AG’s revelations as well as “our own investigation.”

The letter goes on to sever all future business ties. “We have also reached the point such that there is a non-waivable conflict of interest with the Trump Organization,” Mazars wrote. “As a result, we are not able to provide any new work product to the Trump Organization.”

The AG’s office, which got a hold of the letter, filed it in court to bolster its case that Trump, Ivanka Trump, and Don Jr. should be forced to testify about how so many family real estate development projects and properties had wildly fluctuating values that seemed high whenever they needed loans but low whenever it came time to pay taxes.

The Trump Organization did not immediately respond to a request for comment.

The letter also alluded to another matter that criminal investigators reviewed with the Manhattan DA's office: A Trump building apartment in New York City that was provided to Matt Calamari Jr.—a family insider who is now the corporate director of security.

Junior, the son of Trump Organization COO Matthew Calamari Sr., received immunity from a criminal prosecution when he testified before the grand jury investigating company benefits—such as corporate apartments—that may have run afoul of taxing laws, according to a source with direct knowledge of his testimony.

In the firm's Feb. 9 letter, Mazars general counsel William J. Kelly described how accountants had not yet been able to finish preparing the tax paperwork for the former president and first lady, Melania, because they hadn't answered questions about Calamari Jr.'s fringe benefits.

"We believe the only information left to complete those returns is the information regarding the Matt Calimari Jr. apartment. As you know, Donald Bender has been asking for this information for several months but has not received it," Kelly wrote.

Donald Bender, a partner at Mazars, has served as the trusted accountant for Trump and his lieutenants for years, a role that has since drawn scrutiny from law enforcement, according to sources with firsthand knowledge of the transactions and current investigations.

Mazars has found itself in the spotlight since at least 2016, when Trump successfully ran for president but broke with tradition and refused to disclose his tax returns. The firm successfully protected Trump’s tax returns from seeing the light of day, receiving widespread rebuke in the process. And the precedent-establishing Supreme Court fight that ultimately handed those tax documents to the Manhattan DA—but not Congress—bears the firm’s name.