According to the footprints left at the scene, the police could determine the location of the suspect's entry and exit to the sanatorium. However, this was all confidential information of the police, and outsiders were not allowed to know.
Therefore, since the patient named Liu Cheng could tell the exact location, it meant that he might have seen the suspect that night.
It was a pity that Liu Cheng was a mental patient. If he had found out that the suspect had followed the female employee into the toilet, he only needed to shout loudly and he could have saved the female employee's life.
However, Liu Cheng's mental state was abnormal. He had a serious social barrier. He was usually quiet and spoke very little. Otherwise, he would not have been sent to the sanatorium by his family since he was very young.
