Mood in Mysteries

We have been looking for examples of strong mood in our mystery books such as sad, cheerful, exciting, romantic, scary, disguising, etc.).  Identify a particular mood that the author created in your mystery and the strategies the author used to make the reader feel this particular mood (i.e. word choices, speed of writing, actions, mood or tone of the characters, setting descriptions, sounds, etc.)  Make sure to support your answers with examples from your book.