An 89-year-old woman was found dead in her room at a nursing care institution Monday with a sleeveless shirt wrapped around her neck, local police said.
According to police, Rei Toyoda was found in the early morning by a 24-year-old staffer at Hinode Shien in the town of Hinode, western Tokyo.
Police were looking into the possibility of murder and were preparing to conduct an autopsy.
Investigators said the staffer entered Toyoda's room at about 6:30 a.m. to change the bedsheets but found the woman dead in her bed.
She was wearing a T-shirt and slacks, and there was no sign of a struggle, they said.
The rooms at the facility are always left unlocked, they added, and staffers come by every morning to change the bedding. A total of 96 people live at Hinode Shien. Toyoda, originally from Osaka Prefecture, moved there in April 1996.