The Blues Don't Care (Bobby Saxon) by Paul D. Marks
What a time for this book coming out. It is situated in WW II but is very topical now. Bobby Saxon is the only white musician in an all-black band. When one of the bandmembers get accused of murdering a racist Bobby is asked to investigate. It turns out Bobby is pretty good at investigating for an amateur. As you might expect this is not just a mystery but also a story about racism in the forties. What you don't expect is the incredible twist that will surprise you a few chapters in. It is this surprise that adds an extra layer that allows Saxon to give even some more extra social commentary.
I hate saying a book transcends the genre and I honestly usually don't like books that do. This one however does and might win some awards because of it.