At the Villa Rose by A. E. W. Mason [Inspector Hanaud Mysteries #1]

AT THE VILLA ROSE opens at the tables at Monte Carlo where a young Englishman is breaking the bank. Later that evening a murder is committed in a villa near the town, under the most curious circumstances, in which a girl is deeply involved. Hanaud, the great detective, is put upon the trail. Through the most thrilling incidents the story moves along to a conclusion as startling as the crime.