The National Anti-Corruption Commission (NACC) says it has enough evidence to charge 269 former MPs with misconduct in connection with the 2013 charter amendment to make the Senate fully elected.
A sub-panel investigating the former lawmakers will present its evidence and witness testimonies to NACC members in the middle of this month, NACC president Panthep Klanarongran said Wednesday.
The commissioners will probably examine the investigation report afterwards, he said.
If the anti-graft body decides to indict, the matter will be forwarded to the National Legislative Assembly (NLA) for legislators to vote on whether to impeach the former House members, he said.
Mr Panthep said he was confident the evidence would be enough to indict them.
He said the former MPs are accused of several things but most are thought to have acted dishonestly in amending the bill after having already submitted it for a first reading. They allegedly corrected the draft in a way that distorted the version presented before the House. Many did so to further their own personal interests, the NACC president said.
A year ago, the Constitutional Court ruled the MPs had violated Section 68 of the former charter, which prohibits attempts to overthrow the monarchy and unconstitutional efforts to seize power.
Among the 269 former legislators, five or six could also face criminal charges of malfeasance, Mr Panthep added.
They are accused of having swiped several identification cards to register votes for absent colleagues when parliament convened to consider the Senate composition amendment.
Former Democrat MP, Rangsima Rodrasamee, submitted a video showing an ex-Pheu Thai lawmaker, Narisorn Thongtirak, casting a vote several times using other MPs' identification cards.
Mr Narisorn denied the accusation, and claimed he was using spare cards for the voting machine after his own card did not work. Following an investigation, the NACC found these former MPs violated Section 157 of the Criminal Code.
The anti-corruption body has also moved to impeach 38 former senators for their involvement in the charter amendment bill.
The NLA will begin hearings on this on Feb 25.
Former Senate speaker Nikom Wairatpanij and former House speaker Somsak Kiatsuranon were spared by the NLA on Jan 23 on similar charges.