On 31 December 2000, the corpses of 44-year-old Mikio Miyazawa, his 41-year-old wife Yasuko, and their children, 8-year-old Niina and 6-year-old Rei, were discovered by Yasuko's mother, Haruko, at their house in the Kamisoshigaya neighborhood of Setagaya, in the western suburbs of Tokyo.[3] Mikio, Yasuko, and Niina had been stabbed to death while Rei had been strangled.[4] Investigation of the crime scene by the Tokyo Metropolitan Police Department concluded that the family had been murdered on December 30 at around 11:30 p.m. (Japan Standard Time), after which the killer stayed in the house for several hours.[5] Takeshi Tsuchida, the chief of Seijo Police Station, was designated as the person in charge of the investigation at the time until his retirement.[6]