The Drop by Michael Connelly
When evidence links a brutal murder in 1989 to a convicted rapist named Clayton Pell, the case should be water-tight. Pell's DNA was found on the victim - but he was only eight years old at the time.
This not the only mystery Harry Bosch has to solve. A man jumped - or was pushed - from a window. The victim's father is Councilman Irving, who's been intent on destroying Harry's career for years. Now Irving wants Harry to head up the investigation.
Harry uncovers traces of two of the city's deepest secrets: a killer operating for as many as three decades without being detected, and a conspiracy that goes back into the dark history of the police department ...