PHUKET: A 15-year-old Phuket boy killed his stepfather with a tomahawk while the man slept, Phuket police said today.

First, the boy lifted back a mosquito net in the main bedroom at the family home in southern Phuket, an officer told Phuketwan.

Then he removed his sleeping three-year-old stepsister from the bed, placing the child, still asleep, in another room.

The boy then returned to the bedroom, lifted the mosquito net again, and killed his stepfather with two blows to the head with the tomahawk.

Police said the boy and his mother went to Chalong police station today to confess to the brutal murder.

The boy cannot be identified because he is under age, so the stepfather and the mother also cannot be identified.

Family life was brutal, Chalong police in southern Phuket were told. The stepfather would often drink heavily, then beat the mother.

On Monday night, the man went out to a karaoke and returned in the early hours of the following morning, beating his wife yet again.

The 15-year-old awoke to find his mother in tears, with her bags packed, leaving the house.

Soon after, having seen his mother beaten time and time again, the boy took to his stepfather with the tomahawk.

Having killed the man, he rode off on a motorcycle with his young stepsister to join his mother at another house nearby.

A family friend discovered the grisly scene later when he called by the house, having failed to get a response by mobile telephone from either the stepfather or the mother.

Officers say any judge on Phuket is likely to take into account the brutality of the relationship in sentencing the boy to detention.