Generally speaking, the effective period of investigation for the crime of intentional murder and actual murder was 20 years, but the incident regarding Han Yichen happened more than 20 years ago. In other words... the three lives back then had already passed the period of investigation, so Sun Fengzi could not be convicted.
However, this rule had another premise, which was that the offender would not commit the same crime in the future. If they committed it again, the period would be extended. Sun Fengzi had accidentally stepped on this landmine!
Sun Fengzi did not seem to be very clear about the law. She probably only knew that the matter of her setting up three people to die seemed serious. However, as long as the time limit of the legal investigation was over 20 years, nothing would happen. That was why she admitted to it so righteously in the Zhao family that day, even to the extent of being arrogant.
However, this time, she was destined to miscalculate.