Xiangfei Bones

In a river, an excavator dug up a pile of bones. The police determined that the bones were buried for less than ten years. However, there is no record of this incident in all the files of the police station. The only unusual thing among these bones is a copper bell. The bell is not big, but it is held in the hand of a corpse. What is the meaning of this bell? Who are the bones? It also depends on how policewoman Meng Fanjing investigates this case.