A 15-year-old boy held in the stabbing deaths of three family members accompanied police Tuesday as they inspected, among other sites, the house where the killings took place earlier this month in Oita Prefecture.
The inspection began around 8:50 a.m. at the boy's home in Notsu, which is near the house where Kazumasa Iwasaki, 66, and his five family members were attacked early on Aug. 14.
Investigators first re-enacted how the boy allegedly returned to his home after stabbing Iwasaki and his family to get oil to set fire to the house.
According to investigators, the boy, whose name is being withheld as he is a minor, entered the Iwasakis' two-story home at around 2 a.m. Aug. 14 by breaking a downstairs bathroom window.
Police say that after fatally stabbing Iwasaki's 13-year-old grandson, Junya, the youth attacked the other five one by one as they slept, and later fetched kerosene from his home to try to set fire to the murder site.
Iwasaki's 66-year-old wife, Sumiko, his daughter, Tomoko, 41, and Junya died from stab wounds. Iwasaki remains unconscious and in critical condition, while Tomoko's 16-year-old daughter, Mai, sustained severe wounds to the back, and her son, Seiya, 11, to his throat.
The suspect, a first-year student at the same high school as Mai, has admitted the killings.
He reportedly told police he attacked the family in anger because they wrongly accused him of peeping into their bathroom.
However, he later confessed that he had broken into the Iwasakis' house previously to steal money and women's underwear.
The boy reportedly told investigators he was afraid that his parents and neighbors would learn about his sneaking into the Iwasakis' house.