Our Diabolical Case

Summary:
A psychopath detective that the civilians often misunderstood as the criminal because of his psychopathic behavior got asked by a CEO for his help
But why exactly? "I need you to help me investigate my mother's death and find the people who want me dead" it doesn't seem like an easy task though the detective was hesitant at first but the CEO managed to convince the detective. The detective didn't know what he was getting himself into and it only got worse and worse as he investigates and digs further into the past finding out things he shouldn't have.