The cause of death was determined to be carbon monoxide poisoning using a rentan, but the supposed suicide had several inconsistencies, so an investigation was launched by the Saitama Prefectural Police.
[1] As a result of the investigation, they arrived at the doorstep of 34-year-old unemployed woman Kanae Kijima, who was dating Oide.
[2] By January 2010, Kijima had been rearrested for seven charges of fraud, while police simultaneously continued carefully investigating the suspicious deaths.
Kijima, who was a skillful liar, said she lived in a luxury condominium in Nishi-Ikebukuro, paying 200,000 yen every month and driving a rented Mercedes-Benz.
In addition, using the alias of "Sakura Yoshikawa", she claimed that her father was a teacher at the University of Tokyo, while she herself was a piano instructor and food coordinator.
[5] The first criminal trial was filed in the Saitama District Court, for a consolidated hearing on all cases of prosecution (three murders, six counts of fraud/attempted fraud and one theft).
[7] The Saitama District Court, with presiding judge Kazuyuki Okuma, acknowledged the prosecutors' accusations, sentencing Kanae Kijima to death.
The Supreme Court, headed by judge Yoshinobu Onuki, decided to have the first opening session on February 10, 2017.
[19][20][21][22] On April 14, 2017, the Supreme Court Judge Yoshinobu Onuki said, "The killings are intentional and extremely malicious.