I don't want to write about complicated killing techniques. I want to clearly explain the entire killing process from the beginning. There is really no point in planning incredible killing methods. People always die for a reason. I don't want the detective to figure out a bizarre murder scheme to find the real murderer; I want him to focus on finding the murderer's motive.
I don't want to write aimless subplots, especially entangled personal feelings. A detective should indeed have flesh and blood and emotions, but I hope he can be focused enough when investigating. I don't want to see any unnecessary plots. I want to completely focus on the development of the main story without any distractions. If there is no progress in the entire case after one scene, I must abandon it.
I want to simplify the characters and never let any dispensable character appear in my story.
I don't need a clever detective who can suddenly deduce the entire case in a flash of inspiration. I want him to use his experience and perseverance to solve the case. So I'm not going to write a mystery novel, I'm going to write a detective novel.
I want to hold the detective's gaze tightly, and he must be present in every scene, so that he and the readers get the same information, and let him lead the readers to find the truth.