Traitor's Gate — Anne Perry

Someone in the Colonial Office is passing secrets to Germany about England's African strategy. While Police Superintendent Thomas Pitt investigates this matter of treason, he is quietly looking into the tragic "accidental" death of his childhood mentor, Sir Arthur Desmond. Pitt believes he was murdered, and that the crime is connected with the treachery in the government. He is making little progress, until a second murder reverberates through London.

In the small hours of a May morning, a Thames Waterman finds the strangled body of an aristocratic society beauty floating near lonely Traitors Gate. Only then do hard-pressed Pitt and his clever wife, Charlotte, begin to untangle the threads of passion and intrigue, to see clearly the pattern of tragedy and frightening evil that Pitt must deal with, at the risk of his career--and his life.