Bat Wing

The first book of the Paul Harley detective series, featuring voodoo, vampirism, and murder in central London."The Bat Wing" is a supernatural novel by Arthur Henry Sarsfield Ward, known better under his pseudonym, Sax Rohmer. Sax Rohmer was a prolific eng novelist. He is best remembered for his series of novels featuring the master criminal Dr. Fu Manchu. (Excerpt from Wikipedia)