A 13-year-old boy died Wednesday of complications apparently brought on by heatstroke from training at a judo camp in Awaji, Hyogo Prefecture, and not from a beating by an instructor, police said.
Police had initially suspected the beating from Yuki Nagahara's instructor had caused his death, but an autopsy, showing he died of a heart attack, determined there was no direct link between the beating and his death.
Police suspect Nagahara suffered heatstroke after training all day in intense summer heat and are questioning people in charge of the camp to see how hard they pushed the students.
The 29-year-old judo instructor told police he slapped Nagahara in the face and kicked him in the abdomen "for discipline" after supper Tuesday at the hotel where the judo trainees were staying.