The U.S. Attorney's Office is expected to file criminal charges against Rep. Michael Grimm, R-N.Y., the congressman's lawyer told the Washington Examiner Friday evening.

Federal authorities had been investigating Grimm regarding his campaign finances.

Grimm's lawyer, William McGinley, accused the U.S. Attorney's Office of conducting an investigation "plagued by malicious leaks, violations of grand jury secrecy, and strong-arm tactics," and pledged that Grimm would be vindicated.

"From the beginning, the government has pursued a politically driven vendetta against Congressman Grimm and not an independent search for the truth. Congressman Grimm asserts his innocence of any wrongdoing," McGinley said. "We are disappointed by the government's decision, but hardly surprised."

A former FBI special agent and Marine Corps combat veteran, Grimm is himself no stranger to strong-arm tactics. The congressman threatened to throw a reporter off a balcony in January after he was asked a question about his campaign finances.

"I'll break you in half," he told NY1 reporter Michael Scotto. Grimm later apologized.

According to Grimm's lawyer, the New York Republican will continue to serve in Congress despite the pending charges.