ATLANTA — After meeting in closed session for more than three hours on Monday, the state Senate’s ethics committee decided to move forward with a complaint against the chamber’s third most powerful lawmaker after concluding “substantial cause exists” that he violated the Senate’s per diem policy.

The committee initiated its own investigation into the matter and announced they will seek to negotiate a settlement with Sen. Don Balfour, chairman of the powerful Rules committee. The Snellville Republican has served in the Senate since 1993.

“Many times allegations are not always true,” said Sen. John Crosby, who chairs the Ethics committee. “But we’ll be moving forward on this matter.”

The remaining members of the committee in attendance left the meeting without comment. Crosby read briefly from a statement released to the media on the committee’s actions after adjournment, but declined to elaborate on the investigation.

Senate rules dictate that complaints filed with the Ethics committee must be kept confidential until the committee determines there is evidence of a violation. Crosby said Balfour would be served with a copy of the complaint in the next couple of days.

Any settlement that is reached will be a matter of public record. If no settlement is reached, the ethics committee will conduct public hearings on the issue.

Balfour is accused of improperly seeking reimbursements for conducting official business on days when lobbyists reported buying him meals and other perks far from the state Capitol. In a statement on Friday after the hearing, Balfour said, “I still have not been allowed to go before the committee and defend myself.”

“When I do, I am confident the committee will understand that a senator who gave up thousands of dollars in taxpayer-funded pension benefits had no intention of doing anything wrong in a matter of a few hundred dollars,” the statement read.