The Black Box, by Michael Connelly

This was an audio book.

Another great Harry Bosch story, set in nearly contemporary time, ca. 2012. Harry investigates a cold case that dates to the Rodney King LA riots of 1992. At the time of the riots, Bosch and a partner responded to the murder of a woman, but in the thick of action and danger, with the National Guard deployed all around them, they were only able to do a very quick and preliminary investigation of the body and the crime scene, then were forced to rush to another murder. 20 years later, Bosch picks up the threads, and unravels an amazing fabric of conspiracy.

This is the stuff we go to Connelly for.