Police arrested a woman in Sendai on Monday on suspicion of leaving her 2-year-old daughter unattended at their apartment for three days last week, resulting in her death from hypothermia.
Risa Tsuchiya, 25, has admitted to leaving her daughter Hinata at the apartment in Sendai, telling investigators, "I was tired of child rearing. I abandoned my daughter because I wanted to be alone."
The suspect said she left the apartment Thursday, went to work and to a male acquaintance's residence, then went back home three days later, the police said.
Upon returning home on Sunday morning, she found Hinata was not breathing and called the emergency services, they said.
Hinata was naked on the living room floor when the police arrived. An autopsy found she had died of hypothermia and was suffering from malnutrition, they said.
The suspect, a single parent, told the police she fed her daughter when she was at home, and it was the first time she had left her alone for that length of time.
The 35-month-old child weighed 8.6 kilograms, compared with the average of 12.5 kg for girls around that age, based on a 2010 health ministry survey.
Investigators said they suspect the mother may have neglected her frequently. There was no record of her consulting child welfare authorities, according to the police.
"I have never heard a child's voice (in the apartment). I don't know them, but if she had talked to me I would have looked after her daughter, even at night," said Tami Sato, a 69-year-old neighbor.