The treasurer who oversaw the finances of Representative George Santos’s political campaigns has agreed to plead guilty to one or more federal felony charges, according to court papers and an official with the Eastern District of New York.
The bookkeeper, Nancy Marks, has handled the finances of some of New York’s most powerful Republicans over the years and has been dogged by allegations of wrongdoing.
She is expected to appear in federal court in Central Islip, N.Y., on Thursday to formally enter a guilty plea, according to the court official. That account was backed up by three other people familiar with the case.
Ms. Marks waived her right to be indicted by a grand jury and agreed to the as-yet undisclosed charges, according to court papers. This process is sometimes an indication that a defendant intends to cooperate with prosecutors, but not in every case.
If she chooses to cooperate, it could have a significant impact on the case against Mr. Santos, who in May was indicted and charged with 13 counts of wire fraud, money laundering, stealing public funds and lying on federal disclosure forms. He has pleaded not guilty.
His indictment laid out several schemes, including one in which Mr. Santos is accused of pocketing $50,000 in political donations from an unregistered nonprofit. In August, another campaign staff member was indicted in a separate fund-raising scheme.
Mr. Santos has consistently denied any involvement in his campaign’s finances, saying that Ms. Marks was responsible for all filings. He blamed her for any related issues or discrepancies, telling a conservative news outlet earlier this year that a “former fiduciary went rogue.” Her case, which was filed as related to his, will be before the same judge overseeing his case, Joanna Seybert.
Ms. Marks had been one of Mr. Santos’s closest confidantes, working with him from the beginning of his 2020 campaign through his election in 2022. He, in turn, was one of her most lucrative clients, paying her nearly $240,000, including reimbursements from his campaign and associated PACs.
Investigators have interviewed several witnesses in recent weeks who were listed as donors in election filings. They told investigators that they did not in fact make the listed contributions to Mr. Santos, according to a person with direct knowledge of the investigation who was not authorize to discuss it publicly.
A mainstay of Republican politics in Suffolk County, Ms. Marks, 58, has deep ties to Republicans on Long Island, having handled the finances of not only Mr. Santos but also John Flanagan, a former state senator and majority leader, and Lee Zeldin, a former congressman who narrowly lost last year’s governor’s race.
A relentless entrepreneur, Ms. Marks offered clients not only bookkeeping but also printing and consulting services, all out of a converted garage at her home in Shirley, N.Y.
Ms. Marks also managed the finances of numerous conservative groups, including the God Guns and Life super PAC and the 1776 Project PAC, a national organization that funds school board candidates who aim to restrict free expression of gender and teaching about the history of racism in America.
Ms. Marks’s work has attracted the attention of federal prosecutors numerous times before, The New York Times reported earlier this year. In the first instance, prosecutors investigated allegations she had helped broker the sale of a ballot line; in the second, they looked at claims that she had embezzled money from a client. She was never charged.
Ms. Marks left the Santos campaign in January, a month after the news broke that Mr. Santos had fabricated parts of his life story.
Mr. Santos’s finances began attracting scrutiny after The Times and others identified numerous irregularities. Ms. Marks filed to amend his campaign finance reports more than 30 times, during which time expenses appeared and disappeared, often without explanation.
One particularly mysterious pattern was the appearance of dozens of expenses for $199.99 — just pennies below the threshold at which receipts are required. Many of these were made out to “Anonymous.” In subsequent amendments, those payments disappeared from the ledger. But the campaign continued to spend money without disclosing where it went, a practice that led to more than $365,000 in unexplained campaign expenses.
These discrepancies and others led watchdog groups to file complaints with the Federal Election Commission earlier this year for violations of campaign finance law.
Mr. Santos is scheduled to appear in court on Oct. 27.
Michael Gold and Nicholas Fandos contributed reporting.