Justice Department prosecutors have charged Rep. George Santos with federal crimes, three sources familiar with the matter told NBC News, the most significant escalation in a growing number of investigations that have plagued the first-term lawmaker since even earlier. for him to take office.

A source said Santos could turn himself in in federal court in the Eastern District of New York in the morning and is expected to appear in court on Wednesday afternoon. A congressional source said Santos learned of the charges Tuesday. His attorney has not returned requests for comment.

The New York Republican, who faced legal and political pressure to resign from Congress after he admitted lying about parts of his background, is the subject of multiple investigations into his finances and other matters.

No court documents associated with the case were immediately available. CNN first reported pending charges.

In December, two federal law enforcement sources confirmed that federal prosecutors in the Eastern District of New York had opened an investigation into Santos and were examining his finances, including possible improprieties related to financial disclosures and loans he made to his congressional campaign.

Santos did not immediately respond to a request for comment.

Santos announced his re-election campaign last month, despite investigations into a variety of allegations against him in New York state, as well as by the House Ethics Committee.

The House panel announced in early March that it had opened an investigation into Santos to determine whether he may have «engaged in illegal activities» while campaigning for Congress or «failed to adequately disclose information required in statements filed with the House.» «.

The panel also said it would examine whether Santos violated federal conflict of interest laws in connection with his role at a company that provides trust services, as well as allegations of sexual misconduct against him by a potential assistant.

A Navy veteran who accused Santos of disappearing with thousands of dollars from an online fundraising campaign meant to cover his service dog’s life-saving surgery also said he spoke to the FBI about his allegations.

The Nassau County district attorney’s office said in December that it was also investigating «numerous fabrications and inconsistencies» about Santos’ background after The New York Times discovered a number of inconsistencies about his biography, including his education, employment history, and financial dealings. The New York State Attorney General’s Office said that same month that it was “investigating a number of matters” related to Santos.

Although Santos has refused to resign from Congress, he said in late January that recused himself from a pair of assignments on the Small Business and Science committees amid investigations.

Olympia Sonnier contributed.