The National Anti-Corruption Commission (NACC) has decided to bring malfeasance charges against former prime minister Abhisit Vejjajiva and his then-deputy Suthep Thaugsuban in connection with the deadly crackdowns on red-shirt protesters in 2010.
The decision was made during an NACC investigative sub-committee meeting on Tuesday.
Both men are required to submit their defence statements before the investigative panel within two weeks of receiving a letter informing them of the charges, NACC member Vicha Mahakun, who oversees the sub-panel examining the case, said.
They ordered the armed forces to disperse protesters from April 10 until May 19, 2010. The fact is there were more than 90 deaths as a result of these operations, Mr Vicha said.
Mr Abhisit and Mr Suthep did not act appropriately as required by the situation, he said.
Following the April 10 crackdown which led to numerous deaths and injuries, they failed to revise their methods before launching another one, Mr Vicha said.
The action plan decided upon at the policy-making level did not take into consideration the situation on the ground in localities in which the crackdowns occurred, where peaceful protesters and innocent civilians were gathered, he added.
Subsequent inquests concluded that several civilians were killed by the military following Mr Abhisit and Mr Suthep ordering the crackdown.
As a result, there are grounds for the accusation of malfeasance and abuse of authority which could lead to their impeachment, Mr Vicha said.
He said the NACC has yet to decide whether to bring criminal charges against them.
Mr Abhisit posted on his Facebook page after acknowledging the charge that he was ready to defend himself.
He said he would tell the NACC that what he did during that turbulent time was based on the law and within his authority to deal with in a situation where there were armed groups out to stir up violence.
Meanwhile, another NACC sub-committee yesterday agreed to charge 250 former MPs involved in a 2013 charter amendment bid to make the Senate fully elected with unconstitutional acts.
Five others will also face criminal charges but the investigation is still ongoing, Mr Vicha said.
The charge is a result of the Constitutional Court ruling that their attempt to push through the charter bill amendment was unconstitutional.
The anti-graft agency will forward the charges against the 250 lawmakers to the National Legislative Assembly after the commissioners meet next Tuesday.
The 250 former MPs acted unconstitutionally, Mr Vicha said.
Three other former lawmakers who faced the same charges have since died.