Strictly speaking, the special department did not belong to the police department.
They existed independently and only handled special cases that proved to be a crisis to humanity.
Therefore, when Chu Cimo was falsely accused of murder by poisoning in Sea City, Captain Cui realized that this was not a typical case with his intuition and thus took over the investigation.
Unfortunately, the poisoner back then had fled and was not caught.
The enemies of the special department were an evil organization that lurked in the shadows.
This organization had been around for over 40 years and because they were well hidden, ordinary people were unaware of their existence.
The core figures in the organization were well-known scientists in various fields of biomedical research. Hence, the special department's mission was to identify and investigate who was in the organization, to catch those who were manufacturing toxins and biochemical weapons.