In the newly broadcast episode 17, Wu Zhenfeng's true identity was finally exposed. He is an ordinary citizen, not an undercover policeman.
After Wu Zhenfeng returned to China, the first person he met was Vice Captain Chen. Wu Zhenfeng and Chen don't know each other. He found Chen through his father WU GANG's phone records.
After they met, Wu Zhenfeng offered to cooperate with Chen. Wu Zhenfeng is responsible for approaching East Brother, and Chen is responsible for helping Wu Zhenfeng.
Wu Zhenfeng called this cooperation a deal, a win-win deal: Chen can catch the drug dealer and Wu Zhenfeng can avenge his father. It can be seen that in Wu Zhenfeng's eyes, his identity is not offline or undercover, but a collaborator. Since it is a cooperative relationship, he has the right to act independently.