What are the motifs in A Coffin for Dimitrios by Eric Ambler?

Justice is a recurring idea in the novel. Latimer's detective novels portray a perfect justice. A criminal commits a crime, and a moral detective works to bring the criminal to justice. A murderer is proved responsible for his crime and put to death. Justice is clean, neat, and clear-cut. When Latimer enters the underworld of crime, the idea of justice becomes much less clear. The drug dealers who were arrested and sent to jail received minimum sentences. Dimitrios was able to play on the prejudices of the police to get away with murder and frame a black coworker. Latimer finds that he cannot go to the police and turn in Dimitrios. He tries, and the police seem more concerned with whether Latimer is carrying his identity papers than with a serious crime like blackmail.