NEW YORK The former campaign treasurer for U.S. Representative George Santos, who has been indicted on fraud charges, has been arrested and is expected to plead guilty to unspecified criminal charges on Thursday, court records showed.

Nancy Marks was arrested on Thursday and is set to appear in federal court in Central Islip, Long Island at 3 p.m. ET (1900 GMT) after prosecutors said she waived her right to be indicted by a grand jury, the records showed. That usually suggests a defendant has agreed to plead guilty.

A spokesman for the U.S. Attorney's office for the Eastern District of New York declined to comment on the charges Marks faces. Marks' lawyer did not immediately respond to a request for comment.

Santos, a Republican representing parts of Queens and Long Island, was charged in March with defrauding prospective political supporters by laundering funds to pay for his personal expenses and illegally receiving unemployment benefits while he was employed. He is free on $500,000 bail.

The 35-year-old political newcomer has pleaded not guilty and resisted calls to resign for lying about his resume.

Marks told the Federal Election Commission in a Jan. 31 filing that she had resigned as Santos' campaign treasurer.

(Reporting by Luc Cohen in New York; editing by Rami Ayyub)