How to Write a Whodunit

Writing a whodunit (otherwise known as a mystery) can be a challenging yet rewarding experience. And given that mystery novels are among the most popular on Amazon, there's a good chance that you can develop a following and make some money selling your mystery novels. So join me as I share how to write a whodunit. 

In this article, you will learn:
  1. What makes a whodunit different from similar stories.
  2. The most common tropes in whodunit stories.
  3. Tips for writing your mystery. 

What is a Whodunit?

A whodunit is a story that revolves around the solving of a crime—usually a murder. In fact, many people use the terms whodunit and murder mystery interchangeably. 

These stories feature some sort of detective as the protagonist. Sometimes, the detective is a professional, like a police officer or a private eye. Other times, the main character is an amateur sleuth. These can be men or women, young or old. You may even have a young adult whodunit in which the main character is a teenager. 

By the end of the story, the detective will solve the crime and reveal the villain, often in dramatic fashion with some sort of fight or dramatic unmasking. 

Whodunit vs. Thriller and Suspense Stories

Whodunits fall under the broader Mystery, Thriller, & Suspense category. But each of these types of stories has certain factors that make them unique. And while there may be some reader overlap, it's important not to take these differences for granted. 

So if you're interested in mystery writing, you need to know how it differs from other similar stories. 


In a whodunit, the focus is always a crime. It doesn't have to be a murder, but it most often is. As I mentioned earlier, the protagonist is always some kind of detective, amateur or professional. 

Murder mysteries revolve around solving the crime, and it's common for the writer to provide enough clues for the reader to solve the crime before the protagonist has the big reveal at the climax. In this way, a murder mystery novel is a puzzle for readers to try and solve. It speaks to their intellect. But even if they don't solve it, all will become clear by the end of the story. 

Thriller and Suspense

Thriller and suspense novels are different in many ways. While the focus may be a crime, the protagonist doesn't have to be a detective who uses clues to solve the mystery. 

In fact, there may not even be a mystery at the heart of a suspense or thriller novel. The author may choose to show the reader the antagonist from the beginning, thereby creating more tension by letting the reader know something the protagonist doesn't. 

While the detective in a whodunit may not be in direct danger for most of the book, this isn't so with a suspense or thriller novel. In these stories, the main character and/or their loved ones are often in danger. Likewise, the stakes are often much higher than in murder mysteries. The fate of an entire city, a country, or even the whole world may be at stake in a thriller. 

Finally, there is more focus on action in thriller and suspense novels and less focus on the intellectual pursuit of solving the crime with the clues available. 

Different Types of Whodunit Stories

There are several different subgenres to be aware of that fall under the whodunit heading. Here are some of the most common:

  • Police Procedural – Police procedurals are a type of whodunit that focus on a professional detective solving a crime. They're generally grounded in reality and feature actual forensic and crime-solving techniques. They are also often gritty and dark in tone.
    • Examples include the Harry Bosch series by Michael Connelly and Dublin Murder Squad series by Tana French.
  • Cozy Mystery – A cozy mystery is a whodunit without the violence and profanity often found in its gritty counterparts. There are often crime-solving pets involved, and maybe some recipes for delicious cookies and cakes.
    • Examples include the Hercule Poirot series by Agatha Christie, Still Life by Louise Penny, and the Nancy Drew series by Carolyn Keene.
  • Classic Detective Fiction – Usually based before the first half of the 20th century, classic detective fiction is well-known and credited as the birth of the whodunit. The protagonists are highly capable and always in control.
    • Examples include the Sherlock Holmes stories by Sir Arthur Conan Doyle and Edgar Allan Poe's The Murders in the Rue Morgue
  • Noir/Hard Boiled Fiction – Often featuring anti-hero private-eye protagonists, these dark and gritty stories feature highly flawed and emotionally involved detectives.
    • Examples include works by Dashiell Hammett and Raymond Chandler.
  • Locked Room – Also known as a “howdunit,” these murder mysteries revolve around a crime that has taken place in a locked room or some other seemingly impossible location.
    • Examples include The Hunting Party by Lucy Foley and An Unwanted Guest by Shari Lapena 

Research Your Market

Before you get to writing your murder mystery story, it's important to research your market. This can help you determine which subgenre(s) your book will go into, and how competitive they are. You'll also want to ensure you have the right metadata keywords for when you publish. 

One way to do this is to comb through Amazon, gathering data manually. Unfortunately, this is time-intensive and can be less than accurate. 

Another way to do it is to use Publisher Rocket. This tool pulls directly from Amazon and presents it to you in an easy-to-understand format. It gives you essential information you can use when you publish your book, no matter what subgenre of crime fiction whodunit you choose to write in. 

Check out Publisher Rocket here for more information.

How to Write a Whodunit: Writing Tips to Help You

The following tips are crafted to help you write a whodunit no matter your specific type of writing style. Simply incorporate them into your writing process and keep them in mind as you edit and rewrite. 

Craft Your Setting and Crime

Some murder mystery writers start with a crime and work from there, while others like to start with the setting. There's really no right or wrong way, but I find that thinking about these two factors in tandem is a great first step to writing your murder mystery. 

Since the crime is the major plot element that all other subplots will revolve around, it's important to get this right. This includes crafting a believable motive for the antagonist. 

Again, murder is the most common crime in a whodunit, but it's not the only one available. It could be a heist, a kidnapping, a bank robbery, or any other kind of crime you can think of. 

The challenge is making it unique enough to interest the reader and make them want to know who did it and/or how it was done. 

Where your crime takes place is also important because it can influence many factors in your story. If you're going for a dark, gritty vibe, you may want to place your story in a big city. For a small-town feel, you may want your crime to happen in the countryside. 

You'll also want to consider whether you want your story to take place in the present day or sometime in the past. 

Formatting Has Never Been Easier

Write and format professional books with ease.  Never before has creating formatted books been easier.

Click here to see it in action

Place Clues and Likely Suspects

While you don't need to give a single clue that points directly to who committed the crime at the initial crime scene, strategic clue placement is important. The clues at the crime scene should help lead the detective down the path toward the antagonist. However, it should also lead to other suspects along the way. 

Speaking of suspects, there should be a number of them, and they should all seem like ideal suspects with legitimate motives at first. Or at the very least, a lead to check out. 

Some suspects may be complete dead ends, with nothing to help the investigation. Others may have crucial bits of information that can help the detective move on to another likely suspect with a legitimate motive. 

Many murder mystery writers choose to show the reader the culprit early in the story before making it seem like the evidence points to a different suspect. Then, toward the end of the story, the detective will uncover new evidence that points back to the true culprit. 

Include Red Herrings

A red herring is a false clue that leads the detective down the wrong path. However, and perhaps more importantly, it not only leads the detective down the wrong path but also the mystery reader. 

Without strategic red herrings, it will generally be too easy for the reader to determine the true culprit. So make sure you include a false clue or two in your mystery story to throw the reader off of the true criminal's trail. 

Take Time With Character Development

The thing to remember about murder mysteries is that readers will come for the plot (the crime) and stay for the characters. And the most important character is the detective.  

The protagonist needs to be at once likable and flawed. Give the reader a reason to like the character early. Also, provide a glimpse into their flaws, which you can draw out and explore as the story progresses. 

Think about ways to make your detective unique. These traits should help influence the way the detective behaves and their investigative style as well. 

Make the protagonist care about solving the crime. If they can simply go home after their day and leave their work at the office, they won't make a compelling protagonist. If the main character doesn't have a personal stake in solving the crime, it will be hard for the reader to care whether it gets solved either. 

Solve the Crime and Wrap Things Up

As mentioned above, the climax of your detective story should involve the solving of the crime. This is where the major loose ends are tied up and everything about the main plot becomes clear. 

Remember that the motive and the explanation for how the crime was committed need to be satisfactory. If your story is a locked-room mystery, the payoff needs to be unique and exciting. If the solution involves a hidden door that the detective failed to locate, the reader may feel cheated. 

Following the climax, make sure to wrap up any subplots or other loose ends from the narrative. This is also a good place to set up the next book in the series.

Set Writing Goals to Get it Done

When you go weeks or months without writing, it’s much harder to craft a satisfying whodunit. The pieces need to fit together, and it’s much easier to make them do this when you have them fresh in your mind. This is why it’s important to develop a writing habit with a daily or weekly word count goal. The best way to do this is with an automatic word-count tool like the one in Atticus. 

This all-in-one writing and formatting software comes with a number of extra tools to help you on your self-publishing journey. Once you set your specific word count goals, it will automatically record all the words you write in the app. 

When you're done writing and editing, you can use Atticus to turn your manuscript into a ready-to-publish file ready for eBook or print book publishing on Amazon and other online retailers. 

Check out Atticus here to learn more!

How to Write a Whodunit: Solving the Crime

Writing mysteries is fun and exciting but also challenging. A good mystery will have compelling characters, a unique crime, and a plot that revolves around solving the crime and catching the culprit. 

As a mystery writer, it's your job to challenge the reader while providing them with an entertaining story shouldered by a flawed but empathetic character. If a novel sounds like too much of an undertaking, try writing a short story or two first. 

Sell more books on Amazon

Free Download

Amazon Kindle Rankings E-Book

Learn how to rank your Kindle book #1 on Amazon with our collection of time-tested tips and tricks.