Rep. Michael Grimm (R-N.Y.) turned himself in to federal authorities on Monday morning in advance of expected criminal charges concerning his former business dealings.

Multiple media outets reported that Grimm surrendered and was transported to FBI headquarters in Manhattan for processing early Monday. Charges against the congressman are expected to be released later Monday.

Grimm’s growing legal troubles threaten the GOP’s already tenuous hold on the swing district. He's facing former New York City Councilman Domenic Recchia in the general election, and it's too late for Republicans to replace him on the ballot for November.

Those charges will reportedly be related to the congressman’s former ownership of a Manhattan restaurant, Healthalicious, which has ties to an Israeli fundraiser that helped Grimm raise more than $500,000 in contributions, some of which were allegedly improper.

According to the The Washington Post, the restaurant has been fined $88,000 in damages for failing to provide workers compensation. Some of the company’s employees have charged in a lawsuit that the business failed to provide adequate wages and sometimes paid workers in cash to avoid New York taxes and business laws.

It’s unclear whether the charges will ultimately include allegations surrounding his campaign finances, but the investigation surrounding those issues is ongoing.

Grimm’s attorney confirmed Friday that prosecutors were expected to file criminal charges against him, but asserted the congressman’s innocence.

The congressman's attorney, William McGinley, added that “we are disappointed by the government’s decision, but hardly surprised" saying they had "pursued a politically driven vendetta against" Grimm "and not an independent search for the truth."

McGinley said Friday that Grimm had no plans to resign from office.

—This story was updated at 10:30 a.m. to correct Grimm's party affiliation.