how is Villefort's punishment related to his crime?

Villefort has Dantes, who has carried the letter of M. Noitier, put in prison. The Count of Monte Cristo gets his revenge through a three stage plan. He gets Mme. de Villefort sent to prison by giving her poison in order to kill her grandparents. Mme. de Villefort eventually kills herself and her son and it is revealed that Villefort has a son by another woman: a son that he buried alive after he was born. This ruins Villefort's reputation.