A woman was arrested Thursday in the southwestern Japan prefecture of Kumamoto for allegedly hitting her 3-year-old son the previous day in an incident that ultimately led to the boy's death, police said.

The mother, identified as Yuki Saito, is accused of punching her son in the stomach, resulting in him suffering a blow to the head while falling down. He lost consciousness and late Thursday was pronounced dead.

The 27-year-old admitted to the charge, saying, "I lost my temper as (my son) did not behave." The police said they are investigating the case as an incident of bodily injury resulting in death.

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They also suspect that Saito may have hit her son Aoto frequently, based on confirmation from doctors at the hospital of bleeding under the boy's skin.

According to the police, Saito is suspected of hitting her son at their home in Uki at around 10:50 a.m. on Wednesday. The punch caused the boy to fall backward and hit his head on either the floor or a pillar in the house.

The boy's grandmother was visiting at the time and called for an ambulance about 10 minutes after the incident occurred. She was quoted as reporting that Aoto had initially cried but subsequently lost consciousness, although she did not witness the incident herself.

Saito had sought child-rearing guidance from local authorities several years ago. Since that time, the municipal government of Uki has sent a consultant to Saito's home or called her roughly once a week.

Neither the police nor the local consultation center were aware of any signs of child abuse in the family.