 On 18 September 2004, Mami, her husband and two sons strangled Sayoko and shot her 18-year-old son Tatsuyuki and his 17-year-old friend Junichi Hara.They put the victims in a car, which they dumped into a river.On 20 September, they strangled Sayoko's 15-year-old son Joji, whose half-naked body was found on 21 September.