The National Anti-Corruption Commission agreed on Tuesday to pursue impeachment charges against former prime minister Abhisit Vejjajiva and then-deputy Suthep Thaugsuban for ordering the bloody crackdown 2010 crackdown on red-shirt protesters.
The nine-member panel unanimously voted to take action against the two Democrat Party members after the case had been forwarded to it for consideration by a panel investigating the operation that left more than 90 people dead.
Mr Abhisit was the government leader at the time of the dispersal of red-shirt street demonstrators and he delegated authority to Mr Suthep as chairman of the Centre for the Resolution of the Emergency Situation.
NACC spokesman Visha Mahakhun said the anti-graft agency accused the two of abusing authority by ordering soldiers and police to clamp down the protests led by the United Front for Democracy against Dictatorship.
"Mishandling' of the operation at both the policy and operational levels led to the death and injuries of many innocent, unarmed people, the NACC alleged.
Mr Abhisit wrote on his Facebook page that he respected the decision, but vowed to defend for his innocence to restore law and order at the time without any intention of causing loss of life.
The two will be summoned to formally hear the charges and will be given a chance defend themselves before NACC commissioners. The date has not been set.
If, after hearing the defences, the NACC decides to proceed, it will forward the case to the National Legislative Assembly. If assembly members vote against them, the two would be retroactively removed from office and banned from politics for five years.
Mr Suthep - who also led the People Democratic Reform Committee whose protests culminated in May's coup - entered the monkhood last year to pay tribute to those killed and injured in the PDRC's street rallies against the Pheu Thai Party-led government last year. He has resigned from the party.
The NLA voted to impeach former prime minister Yingluck Shinawatra last month for dereliction of duty over her failure to stem corruption and massive losses in the rice-pledging scheme.