Digression Girl

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Continuing on writing characters for fiction, (and having recently watched, “Murder on the Nile” with Kenneth Branagh), I thought it’d be fun to go over some of the basics of writing detectives in fiction. Keep in mind, these aren’t hard-and-fast rules, but they are some of the basic building blocks that can get you started!

  • Observant

Great detectives are usually very observant… though how they get to be that way can be something the writers play with!

Many great detective creations start with a character that is simply observant: they see things and notice what other people seem to miss. Small details, like mud on a pair of shoes, may be significant or not to the case, but a good detective usually sees it before everyone else.

Let’s say a woman died, and the detective is at the crime scene. The observant detective is the one who notices not just that she’s married, or that her husband isn’t on site, but also that their car is missing, when everyone else hasn’t noticed they even had a car.

  • Uses logic

Logic: a proper or reasonable way of thinking about something : sound reasoning. (2) : a science that deals with the rules and processes used in sound thinking and reasoning.

The easy way of looking at this is that A should be processed in such a way as that it leads to B, then to C, and finally to D. A good detective doesn’t assume D right from the start; they look at the evidence, they follow where it leads, and make logical connections along the way.

For instance, a woman is murdered. She’s wearing a wedding ring; the husband is nowhere to be found, and their car is missing. Logical reasoning would lead the detective to believe that because the woman is dead, the husband is missing, and their car is gone, it’s likely the husband did it or is involved.

This isn’t to say they make their CONCLUSION… simply that their logic is fairly sound. The detective doesn’t see the woman dead, the husband missing, and the car gone and say, “Obviously, the BUTLER did it!” Logically, there’s no evidence of that.

  • Has deductive reasoning

This is a little different than straight logic. Deductive reasoning is where the detective uses what they’ve observed, their pattern of logic, and makes an informed “guess”.

Sherlock Holmes is infamous for his deductive reasoning. With very little observable evidence and his wealth of knowledge, he’s usually able to make a very accurate ‘guess’ that is usually right, based on logical conclusions he draws from what he sees.

It’s pretty much his coolest feature.

Let’s use the example of the woman and missing husband again. Sherlock in the same room, might notice that the woman is dead, the husband is missing, the car is missing… and then announce that the husband is a hostage, not the killer.

How does he do this? Well, he probably notices a few things the other cops or detectives didn’t, (the first point I made about being observant), but he also draws connections.

For instance, the woman was hit on the back of her head, but is lying in such a way that she’s on her back with her legs in front of her; that means the body was staged; also, the pictures around the room show the couple as being very happy, and a brand-new box was in the driveway. This detective saw the coding on the label as he walked in, and knows it’s from a baby supply store.

The couple doesn’t have a baby in any of the pictures, they look happy, and they ordered a crib; since the body has also been staged, this detective deduces it’s not actually the husband who struck her, because he loved her and was excited to have a child with her, since it’s his name on the box.

“But, how do we know the husband didn’t move the body?” – asks one of the cops.

At this point, the deductive detective goes into a litany about the tiny observations and what they mean… why a husband who loves his wife would typically close the eyes, even if he killed her in a rage, or how the indentations on the floor indicate the killer had shoes on, when most couples don’t wear shoes in their bed room.

This is the really fun part of most detectives, because their ability to reason is what sets them apart from the other investigators.

  • Is a bit competitive… they like to win, solve the case, catch the bad guy, etc. They probably have trouble letting things go, too.

A good detective is a bit of a bloodhound: once they get the scent of a mystery, they don’t really like letting it go until they’ve figured everything out or caught the bad guy.

They may come from very different walks of life, and the circumstances of how they are pulled into the case may vary, but typically, a good detective is persistent, even in the face of adversity.

In my example of the dead woman, it’s usually the part where the lead detective shows up and yells, “You’re off this case!” to our hero… but we know the hero isn’t going to drop it.

  • Methodical

This is one gets overlooked a bit, but is actually key to writing a good detective. They need to be WRONG somewhere in the story.

That’s actually VERY OKAY, because a good detective should be eliminating possibilities when they aren’t able to magically deduce the right answer.

Not every detective is Sherlock Holmes; some of the best detectives are the best in their perspective stories because they’re very good at finding what didn’t happen and crossing it off the list until they narrow it down to what DID happen.

I worked on the show Bosch, and HIGHLY recommend the first season for exactly this type of detective work. It’s not fast, it’s not easy, but man… you really appreciate the detective who does the WORK.

  • And lastly… they have some style! Though this point is strictly about fiction.

I’m not talking talking about fashion, (although you can throw that in, if you want!)

No… I’m talking about “style”. The character pops off the page against all the other characters because they have some bold choices in their character creation.

Usually this is in their attitude, their temperament, and their skills, but it can also be personal flairs and touches as well.

In a good detective story, all their attributes are brought together and showcased as they move forward through the case.

I love “Miss Congeniality”, because despite being a comedy, Agent Hart is, at the center of her character, a detective/investigator. She’s trying to catch a bad guy, and the story uses ALL of her talents and abilities to crack the case… including talents she didn’t even know she had.

For characters like Sherlock Holmes, Hercule Poirot, Jessica Jones, heck… even Wadsworth from “Clue”… their ‘style’ makes them all wildly different from each other as characters. They have wildly different weaknesses, strengths, habits, idiosyncrasies, and desires, yet they’re all great investigators.

As a writer, I think that’s important. Even if there’s crossover in skills, a good detective should have some personality, some flair, something that makes them unique and real to the universe they inhabit.


  • Observant
  • Logical
  • Uses deductive reasoning
  • Is a bit competitive/likes to win/solve the case
  • Methodical
  • And has some Style

You can play with these, but overall, a good detective character should have a combination of these. You can play with their strengths and weaknesses and why or how they have they skills they do, but overall a good detective is going to need to crack the case, so they need to be written with the skills to do it.


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