The suspect’s body was discovered in her cell in the morning and rushed to the hospital, where she was confirmed dead.
On December 5, the 64-year-old and six other suspects already in custody were arrested for the confinement and murder of 53-year-old Jiro Hashimoto, who was a distant relative.
The seven suspects plus another relative of Sumida were indicted in November for illegally disposing of Hashimoto’s corpse, which was discovered stuffed inside a barrel raised from the bottom of Hinase Harbor in Bizen, Okayama Prefecture.
Sumida was previously indicted for inflicting injury resulting in the death of 66-year-old Kazuko Oe, whose body was discovered in November of 2011 encased in concrete inside a drum stored in a warehouse in Amagasaki City.
All told, investigators have determined that six people, including Hashimoto and Oe, connected to Sumida have died in mysterious circumstances.
On October 14 and 15, police discovered three corpses under the unoccupied Amagasaki home of the 88-year-old grandmother of the wife of the son of Sumida. Her sister-in-law, 59-year-old Mieko Sumida, and daughter-in-law, Rui Sumida, 27, are under prosecution for stealing 3.7 million yen in pension money from the grandmother’s account.
Investigators later announced that one body found under the house was that of Mitsue Ando, 71, the girlfriend of Miyoko Sumida’s elder brother. The other two corpses were those of Mariko Nakashima (29), the older sister of Rui Sumida, and 68-year-old Takashi Tanimoto, whose elder brother was an acquaintance of Miyoko Sumida.
Update: Subsequent news reports from the Sankei Shimbun have indicated that Miyoko Sumida was found to have stopped breathing at 6:10 a.m. Detention cell personnel opened her cell 11 minutes later and called for an ambulance. She was pronounced dead at 7:15 a.m. When she was found, a long-sleeve shirt was wrapped around her neck.