Staff determined the intravenous drips of two patients had been tampered with. Photo / 123rf
Japanese police are investigating the possibility that an "angel of death" killer may have been behind the suspicious deaths of 48 elderly patients at a hospital in Yokohama.
Police initially opened an investigation into the deaths of two patients at the Oguchi Hospital, south-west of Tokyo, after staff determined that their intravenous drips had been tampered with. The plastic drip bags had been pierced and the solution contaminated with a compound, possibly a disinfectant.
Police have since found a further 10 unused intravenous drip bags that had been pierced and have announced that they are looking into the deaths of a further 46 patients over the space of 82 days from July 1.
Authorities at the 85-bed hospital told local media that they were aware of the sharp rise in deaths, but assumed it was because the facility had been accepting more elderly and terminally ill patients.

The investigation is being complicated by the fact that the bodies of the majority of the dead have already been cremated, but police increasingly suspect that the killings were carried out by a person employed at the hospital and with some medical knowledge."We see many people pass away due to the nature of this hospital, but we had the impression that the number of those dying was increasing a bit", a hospital official admitted to Kyodo News.

The 10 drip bags that have subsequently been found to be damaged were stored behind the nurses' desk on the fourth floor of the hospital, where all the suspicious deaths happened.
On July 26, Satoshi Uematsu, a former nursing care attendant at a facility for mentally handicapped people in nearby Sagamihara, killed 19 residents with a knife and injured a further 27 patients and staff.
Uematsu, 26, told police he decided to euthanise the patients "for the benefit of society" and because his demands that the government euthanise the mentally ill had been rebuffed.