Dali looked at me in bewilderment, a glimmer of hope rising in his eyes. I pointed to the ground, "There are footprints here. Although they’re blurred from the wind, we can still infer what happened at the time."

"Look, the murderer's footprints are on top of Luo Youyou's which suggest she came here first with the murderer following in the same direction. What does this tell us?"

Bingxin cried excitedly, "Luo Youyou was running for her life!"

"Yes!” I nodded. “The place where we found the backpack isn’t far from the tire marks, indicating that Luo Youyou escaped from the car. She was fiddling with the thread on the backpack which tells me her hands were free at the time and she was probably sitting in the back of the car. When the killer stopped the vehicle...