If the Dead Rise Not - Philip Kerr

Bernie Gunther, forced to resign as a homicide detective with Berlin's Criminal Police, is now house detective at the famous Adlon Hotel. Two bodies are found - a businessman and a Jewish boxer, and Bernie is drawn into the lives of various hotel guests. One, a beautiful left-wing journalist, is intent on persuading America to boycott the Olympiad. The other, a Chicago gangster, wants to use the Olympics to enrich himself and the Chicago mob.