Photo/Illutration The Okayama prefectural police headquarters (Asahi Shimbun file photo)

TSUYAMA, Okayama Prefecture--A grandmother arrested in connection with the death of her 2-year-old grandson told police she had simply forgotten the boy was in her car on the searingly hot day in question.

Setsuko Shibata, 53, was accused of negligence resulting in death for leaving the child unattended in the vehicle for about nine hours while she went to work, Okayama prefectural police announced Sept. 10 following her arrest by officers of the Tsuyama Police Station.

Shibata, who works as an elderly care assistant, admitted she had been negligent.

Police said 2-year-old Haruto Mese was left in the car between roughly 8:15 a.m. and 5:40 p.m. on Sept. 9. The car was parked in the lot of the hospital where Shibata works.

Police will conduct an autopsy to determine the cause of death.

Shibata was supposed to have taken her grandson to a day care center on behalf of her oldest daughter, but after picking the boy up from her daughter’s home she drove directly to the hospital instead.

Shibata only realized her grandson was still in the back seat of her car after she had finished work for the day. He did not respond when she found him and a colleague called the emergency number.

The parking lot has no roof and the high temperature in Tsuyama on Sept. 9 was 31.7 degrees.