What is the title and author of this book?

Question

The book is a detective story narrated by the detective. It seems as if the police will never find the person who commits the crime, but at the end the detective reveals that he is the killer and walks away scot-free. Thanks for any answers!

Answer 1

Take it to the library... the info specialists (reference) librarians will usually have someone on the staff who's familiar with the genre and they will try to answer this for you.

Answer 2

Sounds like a heap-big cliche of the genre. One book like that (among tons) was The Killer Inside Me by Jim Thompson.