South Korean K-pop star Sulli, who has long been subjected to abusive online comments, has been found dead at her home on the outskirts of Seoul on Monday, local police said.

The body of the 25-year-old was discovered by her manager after Sulli failed to answer the phone. Police said in a statement the former member of top girl group f(x) had been suffering from "severe depression" and her death showed no signs of foul play. An investigation is still ongoing to confirm the exact cause.

Fans across the world said they couldn't believe she had died by suicide because of depression, as she was known for her outspoken stance on women's rights. That was exactly why she had experienced online bullying and harassment.

Sulli, whose real name was Choi Jin-ri, did some acting as child and debuted with f(x) in 2009. In 2014, she suspended her career after struggling with cyber-bullying. She later left the band in 2015 to devote herself to acting and making music as a solo artist.

For years, Sulli showed some signs of her struggle, as she shared some depressing paintings on Instagram. It was later believed to be a suspected self-portrait in which someone has curled up in a ball.

Depression-related suicides have shown an upward trend globally, with show business the "hardest hit area" for depression in past decades. Back in 2017, K-pop star Kim Jong-hyun, good friends with Sulli, struggled with depression and died by suicide at 27.

Chinese pop stars, such as Leslie Cheung from Hong Kong and Qiao Renliang, ended their short lives after being overcome by depression for years. It was also the same with former Linkin Park band singer Chester Bennington, who passed in 2017.

These deaths have sent shockwaves through fan communities. Many are realizing depression is not something that can be overlooked.

Statistics released by the World Health Organization show it is a common illness worldwide, with more than 300 million people affected. It has been one of the leading causes of suicide in 15 to 29-year-olds, but awareness among the general population of its severity is not particularly high.