Crime Fiction Noir Cosy Police Procedural Hard Boiled Detective Thriller Spy

5 Types of Crime Fiction

So, you’ve decided you want to write in the genre of crime fiction, yay!

But wait, did you know there are specific sub-genres, each with their own quirks, rules and structures?

This series looks at the more common types of crime fiction, their subtle differences and how you can write them.

That is not to say these types are wholly different, in fact quite the opposite. What all types of crime fiction have in common of course is, ahem, a crime of some sort. This is not always murder, but is almost always violent in some way.

“There really must be a murder, or at least a major felony – otherwise, what’s the point?” Howard Haycraft

And at the very heart of the story must be at least one character that we really care about. Depending on the point of view you write in, the character we care about may be the unlucky victim, the bright, young detective or we may even find ourselves sympathising or relating to the dastardly criminal of the piece.

Finally, the good guys must win in crime fiction. This tells us the readers that justice will always be served, that good always wins out and we can sleep safely in our beds as our killer rots in prison for the rest of their days.

What we CAN agree on is that we all love a good crime story; in my local W H Smiths, half of the top 10 fiction books are crime, mystery and thrillers.

So let’s get stuck in to learn more about these sub-genres.

The ‘Cosy’

A ‘cosy’ does exactly as it says on the tin. Readers enjoy the usual structure of the crime, the detective and the happy ending but without the messy nuisance of blood, guts and sex.

Yes, a cosy mystery could be thought of as crime fiction lite but is no less nail-biting and enjoyable. Think Agatha Christie’s Miss Marple or a good old episode of Midsomer Murders on ITV.

This sub-genre is often set in a middle-class small town or village. Better yet, an old manor house. Social order is momentarily disrupted by the central crime or serial crimes, and our central protagonist (very often a female and/or an amateur) must work through the puzzle the case presents.

Predictably, our faith in the justice system is restored in the end as the criminal finally receives their comeuppance, and we can all return to the safety of our cosy, warm beds.

The Locked Room Mystery

Perhaps a sub-sub-genre, the ‘locked room mystery’ has all the benefits of a cosy, but is set within seemingly impossible circumstances. For example, a body is discovered in a room that was locked from within and with no other witnesses. Think Jonathon Creek.


A newbie crime writer could convincingly pen a ‘cosy’ without too much prior knowledge of forensics, pathology and well, science.


To write a real humdinger you’d need to think carefully about the all-important ‘puzzle’ your detective must solve; too obvious and your reader will yawn their way through, too ridiculous and they may slam your book shut for good.


The ‘Hard-Boiled’

I always think of a little waddling egg in a detective outfit when I see this phrase, but the central protagonist is certainly not someone to be laughed at in a ‘hard-boiled’ crime novel.

In opposition to the ‘cosy’, all of the gruesome, gory details (and possibly some of the sex) are left in. These stories are often very violent.

The phrase ‘hard-boiled’ became popular in US society circa the 1920s and is often linked to stories set in the city. Our protagonist is more often male, is smart and could be thought of as a bit of a maverick or a ‘tough guy’.

The key here is to ensure your detective has flaws – they shouldn’t be a cut and dry nice character. Though they can show their dark side, under this sub-genre we can be comforted that the detective has an absolute sense of what is right and wrong.

Notable authors include Walter Mosley, Chester Himes and Sara Paretsky.


You could have a lot of fun dreaming up your deeply embedded character flaws here.


Unlike for the ‘cosy’ sub-genre, this will require more research into the gory details involved in a violent crime: blood splatter, wounds etc.


The ‘Noir’

This typically refers to black and white detective mysteries circa 1940-50s. In modern times however, ‘noir’ has become a bit of a buzzword, applied to all kinds of places: Icelandic noir, Mediterranean noir, Nordic noir, tartan noir, even Brighton noir.

‘Noir’ is dark. Think grim, grey, polluted city streets and the downtrodden populace that shuffle along them. ‘Noir’ language is not a happy and optimistic and its central character is not funny and pleasant.

Yes, as a genre it’s not too dissimilar to our ‘hard-boiled’ variety in that we may not actually like the central detective. They may be unpleasant or perhaps just tormented, but either way we are not dealing with a clean cut, nice protagonist.

“The noir hero is a knight in blood caked armor. He’s dirty and he does his best to deny the fact that he’s a hero the whole time.” Frank Miller

Notable writers in the ‘noir’ sub-genre include Grahame Greene, Patricia Highsmith, Ian Rankin and Jo Nesbo.


Again, a flawed character will be tons of fun to create. ‘Noirs’ allow you to have your say on the human condition and really explore hidden torments.


You will need to get comfortable adopting a gritty, direct writing style here.

The ‘Police Procedural’

A sub-genre that concentrates on police methodology primarily, including realistic, in-depth detail of procedures throughout the investigation of the crime; evidence, interviews, case work, arrest etc. Under this genre of ‘specialists’ we also find our forensic pathologists and medical examiners the likes of which Kathy Reichs, Michael Crichton and Patricia Cornwell are revered for.

Most often told from the point of view of the specialist or team themselves, the procedural introduces the reader to an entirely unique perspective; many readers will be learning about the specialism for the first time which is an exciting opportunity to learn new information.


If you wanted to write a modern day hit, you could wow your reader with flashy technology and gadgets used in labs and deep inside incident rooms. Also, check out Marc Goodman’s TED talk for a chilling look into the likely cyber-crime of the future.


I’d say you need a fair amount of specialist knowledge here to convincingly pull this off. You’d need to do your homework on (you guessed it) usual police procedure, police roles, ranks, uniform and weapons. And if you take on the realm of forensic specialism, you are in for a heap of research.

You also need to take not to patronise the reader by over-explaining the detail you need to cover.


The ‘Spy Thriller’

Our central protagonist is a spy working for some kind of intelligence agency, working to solve some sort of crisis. This genre reads like a fast-paced action/adventure and should have your reader flicking through your pages at lightning speed.

The use of insider language to truly convince the reader of your knowledge of the subject is required here. Swot up by perusing works by Robert Ludlum, Arthur Conan Doyle, Tom Clancy and James Patterson.


You are not as limited in possibility here as you don’t have to centre your story explicitly on murder or a violent act; spy thrillers could tackle espionage, theft, forgery.


A notoriously difficult market to crack, having been dominated by the likes of John le Carré who has the advantage of real-life experience of working in this field.

“There is no place where espionage is not possible.” Sun Tzu


Over to you

Do you have a favourite sub-genre and why? Which do you think would be easiest to write in?

Leave me a reply!