I Died Ten Years Ago [Criminal Investigation]

Hatsuko is a senior in high school this year. She doesn't have any lofty ideals. She just wants to get into a good university and find a good job. But one day when she woke up, she found that she had become a policeman named Shen An, who was in charge of a difficult serial murder case. Hatsuko:? * Back then, the "4·04 Serial Murders" shocked the country, but the murderer had not yet been apprehended. The case thus became a famous unsolved case and gradually fell into silence. Ten years later, the murderer committed another crime, sparking heated debate. Shen An was originally one of the police officers responsible for the case. When he woke up one day, he found that he had turned into a girl named Hatsui, who was eighteen years old and was about to take the college entrance examination. Shen An:? * On the day of the school holiday, Hatsuko came to find herself carrying the shell of Shen An. Immediately afterwards, she got a piece of bad news—— She is already dead, died ten years ago. Was the last victim of the "4·04" murder case. Note: 1. Dual timelines to find the murderer 2. Please do not substitute all kinds of fictions into reality. 3. The male protagonist is Shen An ten years later, and the CP is Shen An ten years ago. Intention: Heavenly principles are clear.