What is the theme in Sunset Express: An Elvis Cole Novel by Robert Crais?

The American Legal System is something that is meant to provide justice for its citizens. However, many lawyers can manipulate the system in order to get the result they want. In this novel a man is charged with murder because his wife is dead, he is the last person known to be with her, and the murder weapon was found in his yard. This man's lawyer, however, claims that the murder weapon was placed in his yard by the same officer who found it. This officer, Angela Rossi, has a history of forgetting to read suspects their rights and has been accused of planting evidence in order to get a conviction. This opens a door for the accused murderer's lawyers to turn the spotlight off his client and onto the police officer.