A border police officer from Banteay Meanchey’s Poipet town was beaten to death on Tuesday night by his reportedly mentally ill elder brother.

Authorities said 38-year-old Long Sam Oun, who worked in Preah Vihear province, was visiting his home in Poipet commune’s Chankiri village when he was beaten to death by his 42-year-old brother, Long Sam Oeun, with a metal pipe.

“Though the suspect has no medical documents to show that he has a mental illness, his parents and relatives said he was mentally ill,” said Thin Sindeth, Poipet town’s police chief.

He added that according to the mother’s testimony, Oun had planned a family gathering on Tuesday night during which the brothers got into an argument.

Later that night, Oun was smoking a cigarette outside the house when the mother heard her younger son scream and on running outside found him dead, with Oeun standing next to him with a bloody steel pipe in his hands.

Sindeth said Oeun have been charged with intentional murder and would be sent to provincial court today.