Criminal Investigation: When You First Entered the Police Academy, You Sent Your Professor to Jail?

Gu Chen traveled through the parallel world and became a freshman at Jiangcheng Police University. On the day of registration, the system woke up. Bite! An extremely dangerous criminal has been detected within a radius of 100 meters. His identity is: a criminal psychology professor on the podium! So, with the attention of all the teachers and students in the school, Gu Chen silently took out his handcuffs and walked onto the podium. "Professor, you don't want the secret room murder case 20 years ago to be uncovered, do you?" The whole school was shocked! Old detective: "I asked you to report, and you easily solved the unsolved case that had been backlogged for twenty years?" Bingshan Female CEO: "Gu Chen, as long as you help me catch the real culprit who killed grandpa, I will sign this engagement!" Since then, the police have had a "living king of hell" who makes criminals frightened. You said you committed a high-intelligence crime and didn't leave any evidence? Gu Chen: In front of "Locar's Law of Material Exchange", every breath you take is evidence!