Lawyer Anantachai Chaidej filed a complaint at Chok Chai Police Station in Bangkok on behalf of two of Somkiat’s relatives, Methas Polprasert and Thanyachanok Srichan.

Anantachai said a young woman, believed to be the girlfriend of one of the suspects, posted a message on the Facebook page “C’Gamez Chadade” in which she condemned him and threatened to destroy his law firm.

He said his office was only three blocks from the scene of the deadly attack and he saw what happened and wanted to be a witness in this case.

Somkiat had suffered from a physical disability affecting how he walked.

Anantachai dismissed as a distortion of the truth a press conference held by one of the suspects. He said the suspect claimed that Somkiat harassed them and a knife used in the attack was for self-defence. The lawyer said that in fact, Somkiat retreated and the group assaulted him.

He said he had key evidence, surveillance footage from Siam Commercial Bank, and he would forward the evidence to police.

Thanyachanok said many people saw the assault but had not come forward as witnesses because they had been threatened.

She said Somkiat’s cremation would be postponed until the investigation was completed.

Pol Colonel Chairop Chunnawat, superintendent of Chok Chai Police Station, said the investigation had made good progress but he did not know yet when he would file the case with prosecutors as he still had to question several witnesses and look at the surveillance footage.

He said Pol Colonel Thawirat Srithawatpong was heading an investigation team comprising six officers.

He said police had questioned one of the two girlfriends of the suspects and they would question another woman. Police would check whether that woman created the Facebook page and posted the message.

If she did, he said police would take action against her.

Lt-General Sanit Mahathavorn, acting commissioner of the Metropolitan Police, said police would determine whether the two women instigated the attack by provoking the young men to assault Somkiat as alleged.

He said they would be punished the same as the attackers if they did. If any of them threatened the lawyer, police would take action against them.

Stop Drink Network office director Songkran Pakchokdi called on police to take legal action against those who sold alcohol to the suspects after they admitted that they assaulted the man because they were drunk.

He said the law stated that anyone who sold alcohol to people aged under 20 must face a fine of up to Bt20,000 and/or one year in jail. Two of the six suspects are under 20.

Theerapat Kahawong, another anti-alcohol activist, said shocking statistics showed that more than half of the thousands of underage people in detention committed their crimes after drinking alcohol. “Alcohol is the real murderer that has escaped justice. We will pressure the police to take tough action against alcohol sellers,” he said.