An author’s choice of alibis and motives can make or break a mystery novel because the story revolves around answering two basic questions related to these elements. First: Why would a character want to murder the victim? This is motive. Second: What is the reason a character could not have murdered the victim? This is alibi.
In a murder mystery, each core character should have a reasonable motive for wanting the victim dead followed by an equally strong alibi that makes it seem impossible for him to have committed the crime. In fact, the goal of the murderer is to hide his motive and create a strong alibi. This dilemma creates the need for the sleuth to search out clues that either substantiate character alibis or shatter them.
Motives and alibis enable the mystery writer to create all kinds of flimsy, false or ridiculous alibis that may or may not prove true, enabling the reader to exercise her deductive talents along with the sleuth. Misleading motives provide the opportunity to create red herrings that lead the reader on a wild goose chase. Sometimes the character with the strongest motive and the flimsiest alibi is actually innocent while a character with a solid alibi and no apparent motive is the culprit.
Alibis and motives are the confusing puzzle pieces that form the foundation of the mystery novel.
Other related writing tips:
7 Murder Weapons That Will Challenge The Cleverest Sleuth
How Do Conflict and Crisis Differ in a Mystery Novel?
How Important is Conflict in a Mystery Story?
Developing Characters is No Mystery
How to Write “Killer” Scenes in a Mystery Novel