Columbia, SC (WLTX) - Richland County State Senator John Courson has entered a plea deal on a misconduct in office charge, an arrangement that will also end his over three decades long career in the South Carolina legislature.

Courson entered into a cooperation agreement with the state in a court hearing Monday morning in Columbia.

As part of the arrangement, Courson pleaded guilty to a common law misconduct in office charge. In return, he agreed to resign from the senate seat he's held for 33 years.

Statutory misconduct in office and criminal conspiracy charges were dropped, as long as he cooperates with the state.

Courson had been indicted in March of 2017. He was accused of misconduct in office for allegedly pocketing more than $130,000 in campaign funds, funneled through his political consultant, Richard Quinn and Associates (RQ&A). Solicitor David Pascoe, the prosecutor in the case, said a percentage of the money would come back to Courson.

Prosecutors also claimed Courson voted certain ways that would benefit the clients of RQ&A while in office.

Up until Monday's hearing, he'd maintained his innocence, but he says he is only guilty of "inaccurate filing of reimbursements."

"What I did as far as reimbursing campaign funds was not illegal, but the way, the process I did it, I should have done it differently and I agree with that," says Courson.

"He has been a champion of ethics his entire career and he realized what he did was wrong and he realized that he filed those things incorrectly and now he's making it right," says Rose Mary Parham, Courson's attorney.

The prosecution came as part of the ongoing State House corruption probe being led by Pascoe. Before Courson, House Speaker Bobby Harrell as well as former Representatives Jim Merrill and Rick Quinn Jr. have all taken guilty pleas.

"He did accept responsibility for what he did finally," says First Circuit Solicitor David Pascoe. "I think he realized, Mr. Courson, that he felt bad about the fact that his district has been without a senator for a year now. He did the right thing now of pleading guilty and resigning from office."

Courson had served in the Senate since 1985. From 2012 to 2014, he was the Senate President Pro Tempore, the highest position in that chamber and one of the most powerful figures in state politics.

Courson represented District 20, which runs from southeast Columbia through downtown and out to Irmo. But he'd been suspended from office for months since his indictment, meaning he did not participate in the most recent legislative session.

A special election will now have to take place to fill his seat. Filing for the special election begins June 22nd and runs until noon June 30th. His former constituents will the vote for someone to fill his seat durign the November 6 general election.