There are rules for serious criminal cases. How many years do the police have to solve the case?

There is no relevant law to stipulate the time limit for the detection of major criminal cases. However, within the public security organs, it is generally required to detect cases with great influence in the region and the region within a time limit. As for Yang Moumou you mentioned, he is only a suspect. According to the precedent, no one can be convicted without a court decision! The justice of the law is embodied in not letting go of a bad person and not wronged a good person. The truth will surface, and the real murderer will be punished by law!