Federal prosecutors have started looking into public filings by congressman-elect George Santos amid questions about the source of his wealth, sources familiar with the matter told ABC News.
The sources were careful not to characterize this as a formal investigation and stressed that prosecutors, at this stage, are only looking at publicly available filings.
An attorney for Santos referred ABC News to his press team, who did not immediately respond to a request for comment.
A spokeswoman for the U.S. attorney's office for the Eastern District of New York, which encompasses New York's 3rd Congressional District in Queens and Nassau County that Santos will represent, declined to comment.
In 2020 when he first ran for Congress, Santos listed no assets and a salary of $55,000 in his personal financial disclosure report filed as a House candidate.
But his 2022 personal financial disclosure report filed as a candidate subsequently showed his fortunes had drastically changed: He owned assets valued between $2.6 million and $11.25 million, including an apartment in Rio de Janeiro, a checking account and a savings account.
According to the 2022 disclosure, he reported earning millions between January 2021 through December 2022 from his New York-based company, Devolder Organization. He also reported having a car loan worth between $15,001-$50,000.
Santos did not identify any clients of Devolder on his disclosure form and the company does not appear to have a public presence, such as a website. His campaign website previously called it his "family firm," where he oversaw $80 million in client assets as the managing principal.
According to his campaign disclosure filed with the Federal Election Commission, Santos reported loaning his congressional campaign $705,000 between 2020 and 2022, including $500,000 in March 2022 and a last-minute injection of $125,000 in the final weeks of the 2022 election cycle.
Last week, the FEC sent a letter to the Santos campaign asking to properly itemize the $125,000 loan.
His seemingly sudden wealth, along with other discrepancies in his biography that were first reported by The New York Times, drew the attention of congressional Democrats, including New York Rep. Ritchie Torres, who tweeted this week that "George Santos, a former call center employee falling behind on his rent, lent his campaign a staggering $705,000. Where did all that money come from?"
Santos has admitted to fabricating parts of his background, including his education and employment history, and also exaggerating his Jewish ancestry. But he's insisted in interviews that he's "not a criminal," suggesting he was guilty merely of "embellishing."
"I think humans are flawed, and we all make mistakes," Santos said during an interview with Fox News on Tuesday. "I think we can all look at ourselves in the mirror and admit that once in our life we made a mistake. I'm having to admit this on national television for the whole country to see."
But Santos seemed to backtrack on some of his admissions of actual falsehoods on his resume during the Fox News interview, saying that his claim that he worked for Goldman Sachs and Citigroup is "debatable" and that Link Bridge, a firm he served as vice president for, did "extensive" business with the two Wall Street giants.
Santos continued to defend himself on Fox News, saying he's "not a fraud" and that he worked "damn hard to get where I got my entire life."
He told the news outlet Semafor that he made his money in part by matching sellers of luxury goods like planes and yachts with potential buyers and taking a cut. He described Devolder as working in "deal building" and "specialty consulting" and his clients as "high net worth individuals."
"If you're looking at a $20 million yacht, my referral fee there can be anywhere between $200,000 and $400,000," Santos told Semafor.
The site said he did not answer questions about his past clients.
To questions about his Jewish ancestry, Santos, who had once called himself a "proud American Jew" told the New York Post: "I never claimed to be Jewish... I am Catholic. Because I learned my maternal family had a Jewish background I said I was 'Jew-ish.'"
Separately, the New York attorney general is looking into an animal rescue charity tied to Santos along with an address in Queens where Santos was registered to vote, sources previously told ABC News.
The Nassau County District Attorney's Office is also looking into Santos, a spokesman for the office told ABC News.
District Attorney Anne Donnelly, a Republican who was elected a year ago, said in a statement that "the numerous fabrications and inconsistencies associated with Congressman-Elect Santos are nothing short of stunning. The residents of Nassau County and other parts of the third district must have an honest and accountable representative in Congress. No one is above the law and if a crime was committed in this county, we will prosecute it."
While Santos has acknowledged fabricating parts of his resume, after previously pushing back on the scrutiny about his background, he has said he doesn't intend to resign.
"This [controversy] will not deter me from having good legislative success. I will be effective. I will be good," he told the New York Post this week.
Republican leaders in the House have not commented.
Rep.-elect Nick LaLota, a fellow incoming New York Republican, called for an ethics investigation. Another incoming New York Republican representative, Anthony D'Esposito, tweeted that Santos should "pursue a path of honesty" and a "spirit of sincerity."
ABC News' Hannah Demissie contributed to this report.