A former nurse who allegedly killed as many as 20 elderly patients by injecting their intravenous drips with chemicals is in police custody, Japanese media have reported.
The suspect reportedly said she wanted to control when her patients died.
Police said Wednesday 31-year-old Ayumi Kuboki was in custody over the alleged murder of an 88-year-old man at a hospital in suburban Tokyo. They declined to confirm the broader investigation.
She was arrested Saturday over the alleged murder of the elderly patient in 2016, but she has told police she may have killed up to 20 people, local media said.
It is believed the suspect has not worked as a nurse since the 2016 death.
Kuboki allegedly killed the 88-year-old man by injecting a disinfectant into his drip, it was reported.
The suspect has told police she mixed disinfectant into the intravenous drips of around 20 patients, Jiji Press reported, citing an unnamed police source.
Kuboki reportedly denied any specific grudge against her patients but said she found it difficult to deal with deaths on her shift, and injecting the drips allowed her to control when her patients died.
“Explaining to family members about deaths was cumbersome if a patient died during my working hours,” she told investigators, Jiji said.
The Asahi Shimbun also reported she had admitted injecting the drips of around 20 patients with disinfectant.
Police were already investigating the deaths of two patients, including the 88-year-old.
Jiji reported that after the 2016 murder, police found surfactant — a chemical used for products including detergent and cosmetics — in 50 unused bags for intravenous drips at the hospital.
The same chemical has been found in the bodies of two other patients who died aged 78 and 89, the news agency said.