In Need of an Honorable Killer for Cooperation

A well-known university professor is brutally murdered at his workplace. The killer creates a puzzle from the bones, heart, and fingers of the victim that points to the next victim. However, no one manages to solve the puzzle, and the next murder takes place. At that scene, the killer leaves another puzzle and invites honorable people to join him in the killings. He believes that where humanity has died, only destruction can bring salvation.