Most Murder Mysteries are based on a revenge plot. There are three phases to this:-
1. The Crime. The person seeking revenge seeks retaliation against the person they feel is responsible for a real or imagined crime. In plots where the person seeking revenge is the hero it is important for the writer to provide some sort of moral justification for vengeance. This stage will first establish the normal life of the victim and go into the changes which occur as a result of the crime.
2. Revenge. Usually the protagonist will start by trying to deal with the crime through conventional means, for example calling in the Police. The frustration of this not being successful is an important stage in the building of the plot. The hero will eventually give up and go for ‘wild’ justice, a vigilante effort that usually goes outside the limits of the law. The reader’s loyalty to the hero may be tested resulting in disapproval or, at least, concern for the consequences of the actions being taken.
3. Confrontation. The stage between the protagonist deciding to take revenge into his or her own hands and confrontation often takes the form of a chase. Tempo builds and, if handled well, this will result in excitement and, perhaps, anxiety for the reader. The antagonist may evade the hero’s vengeance several times before final confrontation.
Often, in the final stage of Confrontation, the hero’s carefully laid plans will go wrong and he will need to improvise. If the protagonist is to maintain his position as a hero it is important that the revenge is not more severe than the crime (the punishment must fit the crime) and if this is achieved then the hero is allowed to go unpunished. This ending is cathartic for the audience.