K-pop star, Sulli, formerly of the girl group f(x), was found dead on Monday at the age of 25.

Sulli's manager found her on the second floor of her home in Sujeong-gu, Seongnam, south of the capital city, Seoul. He went to check on her after he couldn't reach her, but he had spoken to her the previous night.

"So far, it seems she killed herself, but we will leave all possibilities open and investigate," a police official said. Police found a note at the scene, but have not analyzed or disclosed any of its contents yet. 

Before joining f(x) in 2009, Sulli - whose real name is Choi Jin-ri - was a child actress, known for playing Princess Seonhwa of Silla in the SBS drama Ballad of Seodong. f(x) was formed my SM Entertainment, South Korea's largest entertainment company that has been responsible for spreading the K-pop movement. The girl group consists of four members - Victoria, Amber, Luna and Krystal - since Sulli's departure in August 2015 to focus on her acting career. She returned to music as a solo artist, in June 2019, with her single "Goblin."

K-pop stars are referred to as idols and idol bullying is a common practice in the industry, leading to serious mental health struggles for the artists. Sulli has publicly spoken out before about the effects of negative comments online. K-pop megastar, Jonghyun, committed suicide in December 2017 and another girl group member, Goo Hara, was found unconscious after writing "Goodbye" on Instagram in May 2019.