That sounds an awful lot like a Jasper Fforde book, which I guess now that I've mentioned it--in the very loosest of terms--could be called a detective novel.
I would certainly recommend Christie, Doyle, Hammet and add Raymond Chandler to the list (I can't believe no one has mentioned him yet...).
On the medical/forensic/whatthefuckever front, Patricia Cornwell's early stuff isn't too bad and I enjoyed Kathy Reichs first few novels, but most of their new stuff is...well, it isn't that good. (Although I hear good things about
Break No Bones. Jeffery Deaver's Lincoln Rhyme books are usually pretty good.
Encyclopedia Brown?!? The Hardy Boys were where it's at.