The National Anti-Corruption Commission (NACC) has agreed to consider five petitions seeking to remove from office 312 MPs and senators who backed the charter amendment draft attempting to change the composition of the Senate.
The 312 legislators include Parliament President Somsak Kiatsuranon and Senate Speaker Nikhom Wairatpanich.
NACC member Prasart Phongsivaphai yesterday said the commission has agreed to combine the five petitions and deal with them as a single case.
The NACC plenary committee will be in charge of the investigation, he said. The petitions have been filed since the Senate passed the third reading of the draft charter amendment on Sept 28.
They include a petition submitted by a group of senators seeking criminal action against the legislators who proposed the amendment. The senators have accused the lawmakers of abuse of authority under the Criminal Code.
Another petition was filed by members of the public and seeks criminal charges against a Pheu Thai MP who is accused of using other MPs' electronic voting cards to vote on their behalf in favour of the amendment.
The other three petitions, which were submitted by the opposition Democrat Party and anti-government senators, seek to remove Mr Somsak and Mr Nikhom as parliament president and Senate speaker respectively.
The pair have been accused of political prejudice while chairing a joint parliamentary session considering the draft charter amendment. Mr Prasart said the NACC will use the Constitution Court's ruling, which was handed down on Wednesday and found the draft amendment violated the charter, as a basis to investigate the case. He said the probe may take "some time".
Meanwhile, the Network of Students and People for Thailand's Reform yesterday handed another petition to the NACC seeking the removal from office of Prime Minister Yingluck Shinawatra, Mr Somsak, Mr Nikhom and the 310 other MPs and senators who proposed the draft charter amendment.
The network accused the group of committing malfeasance in violation of the constitution and politicians' code of ethics.
Wanchai Sornsiri and Prasarn Marukpitak, appointed senators in the anti-government Group of 40, said they would also file an impeachment petition against the 312 MPs and senators with the NACC today. If the petitions were found to have grounds, the NACC would return them to the Senate to launch impeachment proceedings, Mr Prasart said.
Deputy Senate Speaker Surachai Liangboonlertchai yesterday said Mr Somsak and Mr Nikhom can still perform their duties until the NACC decides whether the allegations against them are true.
Democrat spokesman Chavanond Intarakomalyasut said his party will consider filing criminal suits against the Pheu Thai MP who voted on behalf of other MPs using their electronic voting cards.
He claimed the MP had violated the Computer Crime Act.