The FBI has arrested a former top fundraiser for Rep. Michael Grimm (R-N.Y.) on charges of lying on immigration documents, according to published reports.

Ofer Biton, an Israeli citizen, is accused of making false statements about the source of $400,000 he loaned to a company as part of an entrepreneurial visa program administered by the government, the New York Daily News reported. The criminal complaint was filed by the U.S. Attorney’s public corruption unit in Brooklyn, which has been conducting a probe of charges that Grimm accepted illegal campaign donations, according to the newspaper.

Biton has also been at the center of an investigation into allegations that millions of dollars were embezzled from a rabbi who served as spiritual adviser to former Rep. Anthony Weiner (D-N.Y.) and NBA star LeBron James, the Daily News reported. The New York Times reported earlier this year that Biton had raised hundreds of thousands of dollars for Grimm from members of Rabbi Yoshiyahu Yosef Pinto’s congregation.

Grimm has denied any wrongdoing and earlier this year confirmed that the independent Office of Congressional Ethics had ended a preliminary probe into his fundraising. Grimm is running for a second term in a competitive district made up of Staten Island and parts of Brooklyn. His Democratic opponent is Mark Murphy, a former Congressional aide and the son of former Rep. John Murphy (D-N.Y.).

At least four of Grimm’s campaign workers have received subpoenas to testify before a federal grand jury in Brooklyn, the Daily News reported last month.