Abhisit Vejjajiva and Suthep Thaugsuban on Thursday formally denied the murder charges laid against them by the Department of Special Investigation (DSI), Democrat Party deputy leader Thavorn Senneam said.
Mr Thavorn, a member of the Democrat Party's legal team, said the plea was entered after the former prime minister and former deputy prime minister were notified of the charges of murder relating to the death of a taxi driver shot dead during the 2010 riots.
The two men refused to sign a paper acknowledging conditions for their not being detained. The condititons would prohibit them from travelling out of the country without approval from investigators, from meddling with evidence, obstructing the investigation into the case, or doing anything which could cause serious damage.
Both me insisted they would be good citizens and would not attempt to flee.
Mr Thavorn said the two accused denied the charges, because they were not true. Under Article 68 of the Criminal Code, Mr Abhisit and Mr Suthep were not at fault as they were the state authority performing their duty to stop the illegal violence occuring in the country.
Under Article 200 of the Criminal Code, DSI chief Tarit Pengdit, as chief investigator in the case, was at fault for bringing false charges against the two and could be liable to life imprisonment, the Democrat lawyer said.
Moreover, Article 17 of the executive decree for administration in emergency situations, known as the emergency decree, protects those in authority performing their duty under this law from either criminal or disciplinary action, Mr Thavorn said.