Netizen "Autumn Sunflower" suddenly disappeared from the Internet without a trace!

Two months ago, Chan Nok Hang, a girl suffering from selective mutism, made a friend called "Autumn Sunflower" through an online messaging app, and the two quickly became close confidants who talked about everything.

Without warning, "Autumn Sunflower" disappeared, the last online time displayed on the messaging app was three days ago, and his/her blog, Facebook, etc. and other related information were deleted overnight, as if this person never existed.

The great detective Sin Sin took over this bizarre case, but unexpectedly, the investigation involved a suicide attempt a few years ago......

Who is the "Autumn Sunflower" and what does the suicide attempt a few years ago have to do with him/her?