Embattled Rep. Michael Grimm pleaded guilty Tuesday to a single count of tax evasion, according to federal court records.

Grimm (R., N.Y.) was indicted in April on federal charges including mail fraud, wire fraud, tax evasion, employing undocumented workers, and perjury in relation to a Manhattan fast-food restaurant he once co-owned and operated.

In a 20-count indictment, federal prosecutors accused Grimm of underreporting his employees' wages to the Internal Revenue Service, paying them in envelopes full of cash, and said he had lied under oath when he claimed he was not responsible for handling payroll.

Grimm sold his interest in the restaurant before taking office in 2011, according to prosecutors.

The trial was set to begin in February, according to the Associated Press. If convicted, Grimm could have faced a sentence of anywhere from six months for hiring undocumented workers to 20 years for each of the mail and wire fraud charges, prosecutors said.

A former FBI special agent and Marine, he has called himself the victim of a political witch hunt.

Controversy has dogged the Staten Island congressman, who was just elected to his third term, for years.

Federal prosecutors first began investigating Grimm in a probe of an alleged "donor swapping" scheme designed to skirt individual contribution limits to candidates.

In January, Grimm threatened to throw a New York TV reporter off a balcony and break him in half "like a boy" for asking him about the allegations on camera. Video of the incident quickly went viral, and he was pilloried by pundits and on late-night shows.

Despite the controversy, Grimm won reelection in November.

But Tuesday's guilty plea renewed questions about his future in Congress, as Democratic leaders called for his ouster.