Hirata Runa’s family is facing the worst.
The pop star—who was a trainee member of Japanese girls’ idol group DIANNA Project—died of myocarditis, a heart condition caused by influenza, her talent agency confirmed on Sept. 28. She was 8.
Sharing that Runa “has passed away due to myocarditis resulting from influenza,” in a translated statement shared online, her agency added, “We extend our deepest gratitude to all the fans who have supported Hirata Runa and to all those involved who have provided assistance.”
Myocarditis is defined by inflammation of the myocardium, a muscle that is responsible for making the heart contract, according to Mayo Clinic, which can reduce the organ’s ability to pump blood throughout the body.
The statement continued, “Out of respect for the feelings of the bereaved family, we kindly ask that you refrain from making individual inquiries, interviews, or asking questions on social media regarding this matter.”
Just five days before her death, Runa had performed at a concert on Sept. 20, according to Chinese outlet The Standard.