Cold Flat Junction by Martha Grimes

 A second book in a series, a murder mystery from the point of view of a very grown-up 12-year-old. She is largely left to herself and making her way as best she can, with wit and moxie. She is cynical and somewhat jaded but sees through a lot of adult pretensions. She has an attitude but with good reason. A well-drawn character but plot is obscured by too many excursions.