An 18-year-old member of all-female Japanese pop idol group Shiritsu Ebisu Chugaku died Wednesday, apparently after suffering an illness, the police said.

Rina Matsuno was transported by ambulance from her Tokyo home to a hospital where she was pronounced dead. Her parents called an ambulance in the early morning, according to the Metropolitan Police Department.

On Tuesday, Matsuno was absent from the group’s performance in Osaka. She announced her absence through social media, citing poor health.

Shiritsu Ebisu Chugaku, literally meaning “Ebisu private junior high school,” is an eight-member group positioned as a sister group of the popular female idol band Momoiro Clover Z.

Formed in August 2009, Shiritsu Ebisu Chugaku’s motto is “the king of a school talent show,” with its members said to be eternal junior high school students.

Matsuno also worked as a model for women’s fashion magazine “Larme.”