Party members attempted to shed light on the mysterious men in black who had been linked to the red shirt United Front for Democracy against Dictatorship ( UDD) and who were believed by some to have attacked security forces and killed people during the 2010 political violence.
The Democrats on Friday staged a "men in black" caravan to highlight the involvement of the armed men in the 2010 red shirt rallies.
The caravan, led by MPs Tankhun Jitt-itsara and Boonyod Sukthinthai, made five stops along the route where the men in black were reportedly sighted during the April-May rallies.
The recent report by the Truth for Reconciliation Commission (TRC) lent weight to the role played by the men in black in the anti-government protests. It also said the government of the day had to bear responsibility for some of the events.
Army chief Gen Prayuth Chan-ocha said on Friday that the army had information about the black-clad men who attacked security forces on April 10, 2010.
However, he said the information should be verified as the judicial process takes it course instead of being used to trade accusations.
Democrat deputy leader Apirak Kosayodhin told a gathering of party supporters that the TRC clearly said in its report that the men in black used war weapons to attack security forces on April 10, 2010.
But now efforts have been made to distort the facts and deflect the blame to the previous Abhisit government, which handled the protests under emergency rule.
Democrat MP for Rayong Sathit Pitutecha said the men in black were paid to commit crimes and acts of violence, including killing members of security forces and innocent people as well as red shirt protesters during the 2010 political unrest.
He said the Abhisit government had tried to find the men in black, while the Pheu Thai Party-led government was reluctant to uncover the truth.
At the Lumpini Park rally, Democrat leader Abhisit Vejjajiva also released his new book entitled The Truth Without Colours.
Mr Abhisit said he had tried to do everything in his power to avoid the violence but negotiations to end the impasse failed because Thaksin Shinawatra, who was the real boss, was only interested in whitewashing his crimes and not merely in a dissolution of the House.
Mr Abhisit strongly rejected suggestions by red shirt members that "someone who has power beyond the constitution" was involved in the operations to disperse the red shirt protesters.
He insisted his government would take sole responsibility for the mistakes, if any, resulting from the crackdown.
Mr Abhisit said he wanted the country to move forward but there were attempts by some groups to obstruct everything.
He said violence still occurs around country because some groups were trying to distort information and alleged his government had resorted to strong-arm tactics against the red shirts.
Democrat MP Suthep Thaugsuban had tears rolling down his face as he recalled the death of Col Romklao Thuwatham during the April 10 crackdown. Mr Suthep said the Pheu Thai government was trying to unfairly prosecute him and Mr Abhisit for the crackdown.
Mr Suthep was deputy prime minister and director of the Centre for the Resolution of the Emergency Situation, in charge of the crackdown. He said the security forces had followed proper procedures in dealing with the protests.
An emotional Mr Suthep called for justice for soldiers who died to maintain peace and order during the violence.
He said relatives of the dead soldiers received only 400,000 baht in compensation while the red shirts were getting seven million baht.
Pheu Thai deputy spokesman Jirayu Huangsap said the rally was futile as it caused further pain for victims' families.