One of the best parts of a mystery novel is its interactive feeling. Readers attempt to solve the puzzle alongside the sleuth. So, as authors, we must play fair and provide the reader with genuine clues. But what exactly does “playing fair” mean?
For starters, it means providing genuine clues that point a finger at the true murderer. Those clues reveal the murder’s motive, means and opportunity, and are strategically inserted within the plot. They can be subtle. They can be overshadowed by red herrings. They can be shuffled within meaningless information. But, they must be present. And when the murderer’s identity is finally reveled, the reader must be saying, “Of course!” The reader must feel that if she had picked up on that discarded scarf left at the crime scene, she too would have solved the mystery like your sleuth.
That’s playing fair. What’s not fair though is an absence of genuine clues and a big reveal that relies on a gimmick. In other words, when the mystery is finally solved at the end of the book, the concealment can’t be from:
An improbable disguise — I read a book back in the 1980’s where the murderer was pretending to be another character, and had adopted a wig, fake beard and mustache to impersonate that character. The sleuth was interacting with him all throughout the story, then in the big reveal — BOOM! — the beard and mustache come off and the deception was revealed. I was so angry. Not only was it stupid and unbelievable, but a really big cheat.
An implausible twist – All clues point to the kind and gentle town minister, but there’s just no way that he could be the murderer because, you know, he’s so kind and gentle. Still, there’s three witnesses that put him at the scene of the crime. Another witness remembers seeing him act all suspicious, tossing the murder weapon over the side of Old Man Johnson’s Bridge. But in the end, low and behold, we discover the kind and gentle minister really is innocent because he has an evil twin that no one knew existed. I think this might have been shocking and considered an acceptable twist back in the late 1800’s, but today it’s kind of lame. (Although an episode of Supernatural pulled it off pretty well…)
Coincidences and accidental solutions – The hands of fate can intervene to force your sleuth into solving the mystery. Those hands can bring two lovers together. They can reunite old friends and ex-fiancees, but they can not, under any circumstances, provide the opportunity for your sleuth to solve the murder. I read a story in my critique group where, in the last chapter, the sleuth can’t sleep and decides to take a walk. During that late night jaunt, he just happens to hear a woman screaming for help and runs to investigate. He arrives just in time to see his Number One Suspect attacking another woman, leaps into action and thwarts another murder. No. No. No. No. No. No.
Supernatural solutions — In a traditional murder mystery, the Sleuth can’t solve the murder by Divine Intervention or by calling upon the dark forces of Elzabad. He still has to figure out the Whodunit by putting the clues together. And, all those genuine clues still have to add up to motive, means and opportunity. That doesn’t mean there can’t be elements of the supernatural in your story, especially if it crosses into the spirituality or horror genres. Those genre-defining elements can lead to clues, help explain the meaning behind clues, and even lead up to the big confrontation. They just can’t take the place of strategically inserted genuine clues that point to the murderer’s true identity.
The Sleuth’s multiple personality disorder — The Sleuth investigating the murder should not — SURPRISE! SURPRISE! — turn out to have committed the murder. This is a tired twist that most reader’s (and movie goers) can smell coming before the end of the first act. I’m sure it will come back around as fresh again, some day in the distant future. Today though, in a true murder mystery, give your sleuth a good mystery to solve and a Big Bad who gets his comeuppance. And, while we’re at it, main characters who turn out to be ghosts is a little worn for wear too.
In the end, the murderer must be determined by logical deductions — not by gimmicks. You could say a murder mystery is like sending the reader on a deliberate wild-goose chase. But when the solution is found by a gimmick, it’s the same as telling the reader, “Ha Ha! You lost! I actually had the answer up my sleeve the whole time!”
The whodunit must be solved by strictly naturalistic means with several genuine clues, giving the reader a chance to match wits with a rationalistic detective