Japanese police are investigating the poisoning deaths of two elderly patients at a hospital near Tokyo, the latest in a spate of deaths on the same floor of the facility to arouse suspicion.
More than a quarter of Japan's population is aged 65 and above, putting a strain on medical and nursing facilities, where long hours and low pay discourage workers, a problem the government has vowed to tackle.
September's deaths follow the stabbing deaths of 19 residents of a home for the disabled in July, and the indictment of a former worker of a nursing home for killing three residents by throwing them off a balcony.
Police have said autopsies showed poisoning as the cause of death of two 88-year-old male patients on Sept. 18 and 20. Media said the men died as they received intravenous drip injections on the fourth floor of a Yokohama hospital.
A task force has been set up to conduct an investigation, police in the Kanegawa prefecture, south of the capital, said in a statement on Sept. 23.
Police believe someone probably injected disinfectant into their drip feed bags, media said, adding that no arrest had been made, and police were checking if the deaths could be linked to others on the same floor.
Replying to a query from Reuters whether police had told the hospital of autopsy findings that a surfactant, widely used in disinfectant and cleaning products, was present in the bodies, Yuki Uehara, a lawyer for the hospital, said, "Yes".
He did not elaborate.
From July until Sept. 20, as many as 46 other patients died on the same floor, or an average of 18 a month. That outstrips the monthly average of eight deaths on that floor during the 12 months to June, Uehara said.
He added, however, that the number of seriously ill patients in the hospital had risen from April onwards, which could partially explain the increase in the number of deaths.
Japan's social security system is creaking as the numbers of old people grow. Health ministry data show that abuse of elderly patients by nursing facility workers rose 36 percent in the year ending March 2015, to hit a record of 300 cases.