The Don Muang District Court has sentenced Pheu Thai Party member Ruangkrai Leekitwattana to eight months in prison for filing a false complaint with the Election Commission in a defamation case brought by a former Democrat MP.
The court acquitted the second defendant, former Department of Special Investigation director-general Tarit Pengdith.
The lawsuit was brought by former Democrat Party MP Watchara Peththong.
Mr Watchara accused Mr Ruangkrai and Mr Tarit of intentionally filing a false report to the EC which damaged his reputation.
The outspoken Pheu Thai legal expert asked the EC to take action against Mr Watchara for alleged abuse of power when he was a vice chairman of the House Committee on Political Development, Mass Media and Public Participation.
Mr Watchara had ordered Mr Tarit to give his account to the panel on the role of the "men in black" during the political street battles between red-shirt protesters and the military in April and May 2010.
According to Mr Ruangkrai's complaint, Mr Watchara had no authority to summon the DSI chief and his decision to do so favoured the Democrats. Mr Tarit later met the EC and supported Mr Watchara's complaint.
The court read out its ruling on Wednesday, that Mr Ruangkrai had presented no evidence to the court to substantiate his report to the election agency and counter the plaintiff's charge.
The court sentenced him to one year in prison, with no suspension, and then reduced it to eight months because he had cooperated with the court.
The court found Mr Tarit not guilty as he gave his statements to the panel of which Mr Watchara was a member, and to the EC, as an official handling the political violence of the time.
The political violence in 2010 culminated in the final military crackdown on the red-shirted United Front for Democracy against Dictatorship in May.
Mr Ruangkrai said he planned to appeal and was looking to raise 100,000 baht as a guarantee for his release on bail.
