Soul Circus by George P. Pelecanos

Pelecanos writes pretty intense crime novels.  They have some language and sex and lots of drugs and violence.  Just so you know!  This particular novel is another about Derek Strange of Strange Investigations and his experiences investigating in Washington D.C.  Pelecanos is very knowledgeable about the D.C. area.  He presents a city you never see as a tourist that feels very realistic and believable.  In this book, Strange is finding testimony to help defend a drug king, not because he is innocent but because Strange doesn't believe in the death penalty they are seeking for Oliver Granville and because he feels responsible for the death of Granville's father years before.  Pelecanos writes a lot about the "gray area" and this book follows that pattern.  Strange loses someone close to him to a violent death, so it is sad.  It's a fairly quick and definitely easy read.