You are a police officer who is entrusted with uncovering a very large criminal case, involving many victims who were killed by the perpetrator.

You are walking in a hallway, checking the location where the perpetrator killed 5 people in an apartment. Suddenly, you see a shadow in the corner of the hallway. When you approach the shadow, you are surprised by what you find. Xiao, the mastermind behind all this, is trapped with a red thread wrapped around him. "damn."