[Brandon]

Don't see to many of these.
Read some Forgotten Realms ones, they seems to be usually light-hearted mystery/comedy, anyone can reccomend some good ones?

[milamber_reborn]

Halfway through Jordan's Wheel of Time there are a lot of mysteries. More fantasy with mysterious subplots and intrique than fantasy mystery though.

[Alucard]

Though, often scoffed at because of both their popularity and label as children's fluff, the Harry Potter books are some very well done Fantasy Mysteries. They have well thought out plots, and a number of twists that truly caught me off guard. If you haven't tried them yet, I reccomend you do, regardless of your age.

[Barbarossa]

The Vlad Taltos series by Stephen Brust might be your best bet.
Some of the books (Orca) are outright mysteries, others read like the hard boiled detective stories of the 40s by Chandler or Hammet.

[Steven Savile]

You could also try Glen Cook's Garrett PI books - which I *think* are what you are looking for... and hell, with Cook you can't go wrong.

[Jorgen]

You could also try Randall Garrett (it's the writer's name, nothing to do with the main character of Glen Cook's excellent series mentioned above). His Lord Darcy series resembles a lot Chesterton's Father Brown stories imo.

[Ntschotschi]

Lynn Flewlling's "Nightrunner" series has elements of mystery novels imo and there's Umberto Eco's "The name of the rose" of course, which is an outright mystery novel set in medieaval times.
Chine Mieville has a strong mystery novel appeal to me as well.

[Jon Shannow]

Detective/Murder Mistry fantasy books

The Rossacotta books by Dan Crawford about swordswomen ,actually warhammerwomen but I doubt there is such a word, Nimnestl who is cheif bodygaurd to the child king and must defend the regency against any number of plots and conspiricy's and in the process she uselly solves a murder or two..
There are three books so far The Sure Death of a Mouse, Rouse a Sleeping Cat, A Wild Dog and Lone. Full of very enjoyablr characters.

When Demons Walk by Paticia Briggs nice little fantasy about street theif/magicians race to unmask a muderous demon.

[Jon Shannow]

I can not believe I forgot this.
Joel Rosenberg's D'shai books are absolutly brilliant in my view his best books which is saying something with Joel Rosenberg the are two so far, he is always saying he will get back to the series on his web site, they are D'SHAI and Hour of the Octopus about Kami the Discoverer of Truth, read detective, very Sherlock Holmes like in his way of solving puzzles.

Talking about Sherlock Holmes reminds me of another fantasy mystery book Esther Friesner
wrote about him a alternate London dominated by druid magic called Druid's Blood .

[Nevyn]

Raymond E.Feist 'Prince of The Blood',a little bit of mystery happing in this one.