Who is the identity of the murderer Xia Mei?

Who is the murderer Natsume is a trainee policeman, the son of a serial murder victim. 16 years ago, a murder case occurred in a printing factory in Haizhou, and the truth was covered up. 16 years later, the victim's son Natsume went to the police station as an intern to solve the case with Leng.

Leng met a serial killer in those days. At that time, Leng ran away for fear of not pulling the trigger, so Leng was still worried about it. If he is not timid, the murderer will not get away with it.

16 years later, Leng met at the police station. Natsume is an intern, but he doesn't adapt to being a policeman. He was assigned to Leng Xiaobing. Xia Zhi's real identity is the son of a serial murder victim. He escaped from the attic without being found by the murderer. When he grew up, he joined the police force and cooperated with Leng to investigate the truth. Finally, the truth came out, and Leng Xiaobing made up for the regret sixteen years ago. Natsume also avenged his family.