COLUMBIA, S.C. — Former South Carolina House Majority Leader Jim Merrill pleaded guilty Friday to misconduct in office and resigned the seat he’s held since 2000.

Judge Robert Hood sentenced Merrill to a year of probation on the one misdemeanor count. Under the deal, Merrill agrees to continue cooperating with state and federal investigations. He has already been interviewed by State Law Enforcement Division and FBI agents and given information recently corroborated by state law enforcement, said Solicitor David Pascoe, without giving details.

Hood said Merrill’s decision to sit down with investigators in March with no agreement or protection from Pascoe factored into sentencing. Hood told Merrill his willingness to tell the truth “is a testimony to your character and attempts to do the right thing in this case.”

Merrill’s guilty plea makes him the second House leader convicted in a Statehouse corruption investigation, and more could follow. Two other Republican legislators remain suspended amid the probe that began with the 2014 prosecution of longtime state House speaker Bobby Harrell, who pleaded guilty to six misdemeanor campaign-spending violations.

Merrill turned his resignation in to House Speaker Jay Lucas’ office on Thursday evening. It became effective on Friday with his plea. He declined to speak to reporters after the hearing.

Merrill’s indictment last December marked the first since Harrell’s plea and ended speculation that the investigation was dead. He was suspended following the indictment on two counts of misconduct in office and 28 counts of ethics violations. The 50-year-old Charleston Republican had faced up to 66 years in prison and $146,000 in fines if convicted on all 30 counts, three of them felonies. Majority leader from 2004 to 2008, Merrill was accused of illegally profiting from his position.

Pascoe noted the 29 other charges against Merrill have “nothing to do with this plea.” If Merrill doesn’t continue cooperating, Pascoe said he will continue prosecuting the rest.

The conviction involves Merrill’s public relations and political consulting firm, Geechie Communications.

Merrill admitted not reporting income on annual disclosure forms from clients who have lobbyists in the Statehouse. He also admitted he should have recused himself from a vote benefiting a client.

Pascoe said the work for clients was legitimate. “There was never any evidence he received any bribes,” Pascoe said.

Merrill’s attorney, Democratic Rep. Leon Stavrinakis, said his colleague mistakenly left off some of his income.

The December indictments alleged Merrill collected more than $1 million from 2002 through 2016 from clients who hired him to influence decisions. Merrill has been adamant that the work was legitimate and legal.

Former House Majority Leader Rick Quinn faces similar allegations to Merrill’s original indictment. The Lexington Republican, first elected to the House in 1988, was indicted in May on two counts of misconduct in office.

Quinn, majority leader from 1999 to 2004, is the son of veteran Republican strategist Richard Quinn, who owns marketing and political consulting firms. Quinn Jr., also a campaign consultant, owns a direct-mail business. The Quinns have repeatedly said they keep their firms separate, but the indictments allege Rep. Quinn has an economic interest in all of them.

Quinn’s father has not been charged. But the millions of dollars the Quinn firms have collected and spent on clients’ behalf have become a central part of the investigation. Many of Quinn’s clients have testified before the state grand jury.

The other suspended legislator is a longtime Quinn client. GOP Sen. John Courson of Columbia, first elected in 1984, is accused of pocketing more than $130,000 over six years by essentially funneling campaign donations through Richard Quinn’s firm. Courson maintains the charges are false.