Somjet Sitthiworakul was arrested at his home near Pattaya, Chon Buri, for allegedly damaging national security by posting false information on the Internet.

He was accused of feeding false information through the computer system that may cause damage to the security of the nation or cause panic among the public. If convicted, those who are arrested face five year prison terms and/or maximum fines of $4200.

Police on Sunday arrested two suspects, Theeranun Wiphuchanun and Katha Pajariyapong, who have brokerage background on the similar charges. Both were later released on bail.

The Stock Exchange of Thailand (SET) index dropped 7.2 per cent during October 14 and 15 trading sessions as rumours swirled in the bourse over the rumours.