Tokyo: Japanese authorities on Thursday raided the apartment of a nurse who's in custody on suspicion of fatally poisoning at least two elderly patients at a terminal care hospital.

Local media have reported the woman confessed to police she poisoned about 20 patients to have them die when she was off-duty and could avoid the trouble of explaining the deaths to their families.

Kanagawa prefectural police said they searched 31-year-old Ayumi Kuboki's apartment in Yokohama, near Tokyo, for more evidence in the case.

Police investigators head to the house of suspect Ayumi Kuboki in Yokohama. Credit:AP

Kuboki was arrested on Saturday on suspicion of killing two men in 2016 by injecting disinfectant containing benzalkonium chloride into their intravenous drips at the former Oguchi Hospital — since renamed Yokohama Hajime Hospital — a Kanagawa police official said on condition of anonymity, citing department rules.