A multi-agency panel has set Friday as the deadline to finish a probe into the killing of four alleged insurgents by security officers in Pattani.
Responding to calls for fairness from relatives of the deceased, Deputy Prime Minister Gen Prawit Wongsuwon on Monday assured the government will adhere to the law, which "never takes sides".
Gen Prawit, also the defence minister, promised the case will be investigated thoroughly and confirmed a fact-finding team is scheduled to present the results of its investigation on Friday.
The team was appointed by the Internal Security Operation Command Region 4 Forward Command after the killing of the four men — Saddam Wanu, 24, Kholid Samaeng, 24, Madaree Maeroh, 23 and Suhaimee Sen, 32 — during a clash with security forces in Moo 6 of Ban To Chut in Pattani's Thung Yang Daeng district last Wednesday.
Waedoramae Mamingji, chairman of the Pattani Islamic Committee, leads the team whose members include religious and community leaders, representatives of the Region 4 Forward Command, the Islamic University and police.
The team held its first meeting on Sunday and is currently gathering information. It is working to a tight deadline after relatives raised concerns about the deaths.
Officers suspect the four were members of a separatist group planning to discredit the government's Thung Yang Daeng model, which promotes closer co-operation between security officers and villagers in the area.
However, some of the victims' parents rejected the officers' claim, saying their sons had nothing to do with the plot.
Mahama Sen, father of Suhaimee, said he did not believe his son was an insurgent because he was considering a job at the Territorial Defence Volunteers Administrative Bureau under the Interior Ministry.
"Don't authorities have this information?" Mr Mahama asked, insisting the claim his son was a member of the Runda Kumpulan Kecil (RKK) guerrilla group is baseless.
Two of Suhaimee's relatives have been killed in the insurgency. One was a former village assistant and the other was a territorial defence volunteer.
Suhaimee would have replaced his relatives in these jobs if he had not been killed, Mr Mahama said.
According to Mr Mahama, on Wednesday his son said he was giving his friend a lift on his motorcycle to a house in Ban To Chut.
Suhaimee and the three others were shot dead during an anti-insurgency raid on the house. They are accused of opening fire at officers first.
The slaying of the men has raised questions among many civic groups, who, in a statement issued on Sunday, urged authorities to bring any wrongdoers to justice and demanded officers take responsibility for their actions if it is proved they killed the men unlawfully.