Maria Schneider's Under Witch
Moon Shadow Series might be interesting. Adriel isn't officially a detective, but she ends up involved in a number of murders, and the books have a definite whodunnit feel to them.
She might also like Diana Rowland's
Mark of the Demon. I haven't personally read that one, but Diana's books have been selling quite well, she's contracted for several more with her publisher, and she has a number of raving fans.