Local police have started a murder investigation after a seven-year-old boy suffered injuries and died at a family home in the southwestern Japanese prefecture of Oita early Friday morning, local press reported. The elementary schoolboy was found unconscious at around 2:30 a. m. local time in a room of his home in central Oita City of the prefecture, and was sent to a nearby hospital where he was later confirmed dead, according to the daily Mainichi Shimbun. The report cited police officials as saying that since the boy has had no major medical problems, investigators believe his death was rather accidental. The report added that there are five people in his family and all of them were at home at the time of discovery.