HAT YAI, Thailand (AP) — Police say two Thai army volunteers have confessed they shot dead three boys and wounded their parents to seek revenge for one of their families.

Police Maj. Gen. Pattanawut Angkanawin said Monday the army rangers were arrested on Saturday in the southern province of Narathiwat.

He said the pair admitted they fired rifles and a pistol into a house in Bacho district in Narathiwat province and killed three brothers, aged 6, 9, and 11, last month.

Pattanawut said one of the suspects said he was seeking revenge for his brother, who he believed was killed by the victims’ family.

Police are seeking another accomplice.

They say the attack was not connected to an Islamic insurgency in Thailand’s three southernmost provinces. More than 5,000 people have been killed since 2004.