Kim Jong-hyun, the lead singer of popular South Korean boy band SHINee died on Monday in a suicide.Yonhap news agency said authorities found burned coal briquettes, which produce carbon monoxide, in a frying pan in Kim's hotel room.

FILE - In this Oct. 4, 2016, file photo, Kim Jong-hyun, a member of South Korean K-pop group SHINee, poses for the media before a showcase for the group's album "1 of 1" in Seoul, South Korea. Kim Jong-hyun, better known by the stage name Jonghyun, was found unconscious at a residence hotel in Seoul and was pronounced dead later at a nearby hospital, Seoul police said Monday Dec. 18, 2017. (AP Photo/Lee Jin-man, File)

Kim Jong-hyun, better known by the stage name Jonghyun, was found unconscious at a residence hotel in Seoul and was later pronounced dead at a nearby hospital, Seoul police said.
Police said Kim's sister told them that the singer sent her text messages such as "Final farewell" and "I've had difficulties" before his death.
Jang Hee-yeon, lead singer of rock group Dear Cloud, posted what she called Kim’s suicide note online, with a photo of the total darkness.

“I’m broken from the inside ... It’s amazing that it hurts this much. No one alive is more tormented nor weaker than myself.” Kim wrote, ending the note by saying: “Tell me this is enough, that I did well. Even if you can’t smile, don’t send me off blaming me. You did well, you did good. Goodbye.”

Kim debuted in 2008 as the main singer of SHINee, and cultivated a career as both a group member and a solo singer-song writer. His last public appearance was at a solo concert titled "Inspired" on Dec. 9-10 in Seoul, and he was scheduled to hold concerts with SHINee members in Tokyo and Osaka in February, Yonhap said.

South Korea has one of the highest suicide rates among developed countries. A string of high-profile figures, including a former president and business executives, have killed themselves in recent years.