Closed Loop: Subjective and Correct

The largest city in the federation, Nancheng, is a city covered by 1,200 surveillance cameras. A former federal judge fell from the observation deck, a wealthy businessman died of heart failure in the VIP ward, and a technical expert suffocated and died on the subway... Seven deaths, no murder weapon, no fingerprints, no suspects. During the investigation, the detective of the Federal Crime Team discovered that all the deceased were related to an old case five years ago, and the confirmation of the settlement of that unjust case had his autograph. The murderer has already taken himself out. He only needs to design a process to let unsuspecting people complete a small step each - and then death will occur. [Closed loop: subjective and correct] A perfect set of murders borrowed from everyone...