Police in Oita Prefecture arrested a 37-year-old woman Saturday on suspicion of beating her 4-year-old son to death at their home.
Rie Kinjo has admitted to punching her son in the head and chest and hitting him with an umbrella between 8 a.m. and 5 p.m. Thursday, the police said, adding officers found the boy's body at Kinjo's home in Beppu on Friday afternoon after she turned herself in.
Kinjo said she found the boy dead Friday morning when she went to wake him up. She said she had beaten the boy the previous day, but claimed she had not intended to kill him.
Kinjo, who is unemployed, was living with her partner, her son and his younger brother.