COLUMBIA, S.C. (AP, WLTX) - A longtime member of the South Carolina legislature has pleaded guilty to a misdemeanor charge in connection with the ongoing probe of corruption in South Carolina's government.

Former Rep. Rick Quinn Jr. and his father, Richard Quinn Sr., one of the most powerful men in South Carolina politics, appeared in court Wednesday afternoon. They'd earlier been indicted on multiple charges.

But during the hearing, Quinn Jr. only plead guilty to a charge of misconduct in office. He gave a limited admission of guilt, only saying that he failed to report to the House Ethics Committee the name of a lobbying group that had leased office space from a company that he had a business tie to.

He could face a maximum of a year in prison. Two other charges against him were dropped.

Sentencing will take place at a later date.

Prior to the hearing, Quinn resigned from office, which was also part of the plea agreement.

As part of the plea, his father had all individual charges dismissed against him, and admitted to no personal wrongdoing. The senior Quinn has agreed to cooperate with the South Carolina Law Enforcement Division and will testify against others in the ongoing corruption probe in exchange for immunity.

However, he did agree to enter a guilty plea on behalf of one of his companies, First Impressions. The company said that one of their former employees failed to register as a lobbyist.

The company also agreed to pay a $300,000 fine.

While the plea was limited, the prosecutor in the case, Solicitor David Pascoe, the leader of the corruption probe, used the opportunity to make the claim that Rick Quinn Jr. and his father's company, Richard Quinn and Associates, acted as lobbyists and personally profited from Quinn Jr.'s position as a member of the legislature.

Pascoe said Quinn Jr. lied repeatedly over the years when he said he had no financial connection to his father's company. Pascoe, though, said Quinn said was an employee, officer, and boss at the company, and actively worked to influence legislation.

Quinn and Associates is one of the top political consulting firms in the state, and the senior Quinn is seen as one of the most influential behind the scenes movers in Palmetto State politics.

Pascoe said Quinn Jr. accepted over $4 million from lobbyist while service as a legislator. Pascoe also said multiple large companies had paid Richard Quinn and Associates but never reported the money.

He said Quinn Jr. at one point even tried to get the investigation into he and his father's business shut down.

Pascoe said the family was "lucky" to get the deal they got. "It's a tremendous offer," he said. "There's been no one more corrupt than Rick Quinn in Columbia, South Carolina, and no entity more corrupt, than Richard Quinn and Associates."

When asked by the judge why, if there was such a powerful case against them, he was letting them off with a limited plea, Pascoe said the father would be testifying next month, and that the information he had was valuable. He said if Quinn Sr. lied, he'd face perjury charges.

He also cited the cost of trying the case.

But Quinn's attorney, Johnny Gasser, said Pascoe gave them the deal because the prosecutor knew he had weaknesses in his case. "No prosecutor would ever acknowledge that, no prosecutor would ever admit that."

He said there was no proof that Quinn Jr. was involved in his father's businesses or was an owner.

In his resignation letter, Quinn told House Speaker Jay Lucas that his 21 years serving in the Legislature is one of the great honors in his life.

So far, two other lawmakers have resigned and pleaded guilty. Charges are pending against State Sen. John Courson and two other former lawmakers.

The probe began in 2013 after a SLED case filed mentioned several top lawmakers. The probe also led to the downfall and resignation of former South Carolina House Speaker Bobby Harrell.