Thailand's former Prime Minister Abhisit Vejjajiva and his then-deputy PM reported themselves to police investigators and denied all charges on Thursday after he was pressed murder charge on a case of a man killed during 2010 crackdown on protesters.

Last week, the country's Department of Special Investigation ( DSI) decided to press murder charges against Abhisit and then deputy prime minister Suthep Thuagsuban for conspiring to murder Phan Kamkong, a taxi driver.

Phan who was shot dead by soldiers under the command of the Centre for the Resolution of the Emergency Situation (CRES) which was specially set up to deal with the civil protest staged by anti- establishment "Red-shirt" in May 2010.

The charges were made against Abhisit in his capacity as prime minister overseeing CRES and Suthep who was appointed the CRES's director.

Greeted by supporters at the Democrat Party head office before leaving for the DSI headquarters on Thursday morning, Abhisit thanked them for not gathering at the DSI to avoid possible confrontation with the anti-establishment Red Shirt activists, most of them relatives of people killed during the crackdown.

Democrat Party chief adviser and former prime minister Chuan Leekpai, and other senior party members also accompanied the two to the DSI office.

At about 4 p.m. local time, Democrat Party deputy leader Thavorn Senneam told reporters that the two denied the murder charges laid against them.

The two men refused to sign a paper acknowledging conditions for their not being detained. The conditions 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. However, both of them insisted they would be good citizens and would not attempt to flee, Thavorn added.

According to the investigator, the two were informed of murder charges laid against them in connection with the death of the taxi driver who the Criminal Court ruled was hit by bullets fired by soldiers taking part in a military crackdown. After hearing the charges, they were undergo an interrogation session.

At press time, Abhisit and Suthep have not come out of the DSI office.

Abhisit said earlier that they never intended to assault the public but they had the responsibility to return order for the public when violence occurred and when weapons were used. "And unfortunately, some people died," Abhisit told BBC reporter during his interview in London last week. The two insisted they would not runaway and confidence of their innocence.

The case of taxi driver was the first proceeded to the court among other more than 30 cases of death arising from the riots during the crackdown on Red Shirt protesters in 2010.

From March to May 2010, several thousands Red Shirts gathered in Bangkok and called for Abhisit administration to resolve the parliament. After the Red Shirts had seized the heart of Bangkok's business zone more than a month, the military, under supervision of the CRES, cracked down on protesters, resulting in almost 100 people died and more than 2,000 people injured.