Photo/Illutration China Kawamoto, 3, died of heatstroke after she was left behind in this kindergarten bus in Makinohara, Shizuoka Prefecture, on Sept. 5. (Akari Uozumi)

MAKINOHARA, Shizuoka Prefecture--The former head of a local kindergarten and three others were referred to prosecutors over the tragic death of a 3-year-old girl who was left on the school bus in the scorching summer heat in September.

Shizuoka prefectural police made the announcement on Dec. 5.

Police allege professional negligence resulting in the death of China Kawamoto, who died of heatstroke after she was left in the Kawasaki Kindergarten school bus.

The former head of the kindergarten, Tatsuyoshi Masuda, 73, drove the bus on the day she died. The other three are a 76-year-old temporary staffer who was on the bus, China’s homeroom teacher and the assistant homeroom teacher.

All of them resigned after the incident.

Police did not reveal whether the four deny or admit to the charges. But according to a lawyer representing Haibara Gakuen, the operator of the kindergarten, Masuda has admitted to the charge.

Haibara Gakuen said in a statement it issued on Dec. 5 that it takes this case “very seriously.”

“We offer our deepest condolences to the girl and apologies to her bereaved family,” it said.

Police allege the four left China behind on the school bus on Sept. 5 causing her to die from heatstroke--despite that they had a professional duty to protect the children.

Police said Masuda and the temporary staff locked the bus without sufficiently checking for whether any children were left behind, while the homeroom teacher and her assistant failed to contact China’s parents despite noticing her absence.

China was left in the bus for about five hours after it arrived on the morning of Sept. 5, and at one point that day the temperature soared to 30.5 degrees in Makinohara.

When prefectural police conducted an experiment in mid-September to replicate the conditions, the temperature inside the bus topped 40 degrees.

Officials later found China’s empty water bottle and the clothes she likely removed in the sweltering heat in the school bus.

(This article was written by Yuichi Koyama and Sokichi Kuroda.)