For what I have known, there are several key suspicions:
1)Chan was found entirely naked when the police claimed she committed suicide
2)right after Chan was missing and much earlier than the news came out, Chan’s friends approach her parents for Chan’s whereabouts. Her parents told her friends not to ask or investigate the case any more.
3) Chan’s last message to her friends was sent from MeiFoo, West Kowloon, saying that she’s going home. However, Chan’s body was found in YauTong, East Kowloon, and her personal belongings including her mobile phone and wallet were in her school in TseongKwanO, East Kowloon.
4) According to her friends and her own social media websites, Chan was actively participated in protests since June
These are all I knew by far, I might be wrong, feel free to correct me bros and sis
