Guai Qi Zhentan

Wang You Cai, who has the abilities of a detective, originally planned to take a break after resigning as a cop; but to his dismay, his friend experienced an unexplainable tragic death. As a detective, he has decided to solve the mystery; while searching for answers, he met the female Mc Zhen Meng, who is part of a mysterious group; confidentially, they start to uncover the truth of many other obnoxious situations.

(Source: Manga Bilibili, translated)