A 23-year-old woman was arrested Thursday over allegedly causing fatal injuries to her 3-month-old son by punching him repeatedly at their home in the western Japanese city of Takamatsu, with the mother suspected of having been involved in abusing the boy, police said.
Ayami Tsumori admitted to the charge, saying, "I punched my child in the head as he would not stop crying," the police said, adding that an autopsy showed the baby's skull and ribs were broken.
According to the police, the woman is suspected of having used violence against her son Minato at some point between late July and Thursday.
Tsumori called an ambulance to report that her son was not breathing at around 8 a.m. Thursday. When rescue workers arrived at the house, they found Minato unconscious and he was later pronounced dead at a hospital.
The woman's 25-year-old husband and 1-year-old daughter also live in the house. The husband was out for work when rescue workers rushed to the scene.
The couple told the police that Minato had been alive on Wednesday night. No indications of the daughter having been abused were found, the police said.