U.S. Representative Michael Grimm, R-N.Y., talks to reporters after a meeting at the U. S. Capitol in Washington, in this Jan. 2, 2013 file photo. Gary Cameron / Reuters

U.S. Rep. Michael Grimm, R-N.Y., aligned with the tea party during his 2010 election campaign, surrendered to authorities Monday in New York to face a 20-count federal indictment that includes charges of mail, wire and tax fraud.

Prosecutors charged Grimm with engaging in schemes to underreport wages for restaurant workers, including some who were in the country illegally. They also accused him of concealing more than $1 million in sales and wages.

Grimm once was an investor in a Manhattan health food restaurant called Healthalicious that has been accused in a lawsuit of cheating its workers and fined by the state for failing to carry workers' compensation. He has said he sold his interest in 2009.

Authorities said that when Grimm was deposed by an attorney representing former employees in the lawsuit, he lied under oath about his allegedly fraudulent business practices. The charges are the result of a two-year-long investigation.

The congressman was awaiting arraignment in Brooklyn federal court as of Monday morning.

Grimm, 44, a former Marine and FBI agent, represents parts of the New York City boroughs of Staten Island and Brooklyn.

"Rep. Grimm billed himself as a patriot and an American hero," said George Venizelos, head of the FBI's New York office. "But Rep. Grimm was anything but an upstanding citizen. He cheated, evaded and then lied."

He is the only Republican congressman who represents New York City. His party will likely be unable to replace him as a candidate to stand for re-election in November, since an election registration deadline has already passed, according to The Washington Post.

Last week Grimm's attorney, William McGinley, revealed that prosecutors told his client that he would be charged.

"From the beginning, the government has pursued a politically driven vendetta against Congressman Grimm and not an independent search for the truth," McGinley said in a statement Friday.

"Congressman Grimm asserts his innocence of any wrongdoing."

McGinley did not immediately respond to a request for comment from Al Jazeera.

After the House Ethics Committee announced last fall that Grimm was under investigation, the panel said it would defer its inquiry because of a separate Department of Justice investigation.

During the 2010 race, Grimm acknowledged receiving $250,000 to $300,000 in contributions from followers of an Israeli rabbi, Yoshiyahu Yosef Pinto. Some members of Pinto's congregation subsequently said they made tens of thousands of dollars in illegal contributions, including gifts passed through straw donors.

A straw donation is an illegal form of campaign contribution, in which someone gives money on behalf of another person. Receiving such a donation also violates federal law.

Grimm has denied knowledge of any improprieties. The Israeli businessman who served as Grimm's liaison to Pinto's followers, Ofer Biton, pleaded guilty in August to an immigration fraud charge.

Three days after that guilty plea, the FBI filed a sealed criminal complaint accusing Diana Durand, a Houston woman who had been romantically involved with Grimm, of using straw donors to make illegal campaign contributions.

On Friday federal authorities in Brooklyn charged Durand with making those contributions. Prosecutors also accused her of making false statements to the FBI when she said she didn't reimburse straw donors for their contributions to Grimm's campaign.

A House member who has been indicted does not lose any rights or privileges under federal law or the chamber's rules, according to a report by the nonpartisan Congressional Research Service.

Grimm doesn’t serve as the chair of any congressional committees. If he did, party rules would require him to temporarily step aside because of the indictment.

He made headlines in January after confronting a New York City cable news station reporter, Michael Scotto, who tried to question him about a long-running FBI investigation into campaign finance while they were on a balcony in the Capitol in Washington.

After Scotto finished his report, Grimm stormed back, leaned into him and said, "Let me be clear to you. If you ever do that to me again, I'll throw you off this [expletive] balcony."

Al Jazeera and The Associated Press