In fact, before last night's inquiry, Fang Ze had been suspecting that Mr. Wang was the serial killer.
Therefore, last night, Fang Ze continued to question along that line of thought.
However, he felt that directly addressing the case, Mr. Wang would most likely not recall the details in his heart. Thus, inspired by a flash of Spiritual Light, he decided to start from the relationships between the victims and Mr. Wang.
According to the reports of previous life criminal psychology research, serial killers usually have certain psychological disorders and abnormalities. They seek the pleasure of killing and feel pleasure and a sense of accomplishment from their murderous acts.
This leads to a significant portion of serial killers occasionally returning to the crime scene to seek that "special feeling."
The same principle applies in the Late-Night Investigation Room.
If Fang Ze directly questioned the case, Mr. Wang might become guarded and say nothing.