The Siamese Connection, The Vampire of Siam IV by Jim Newport
The fourth book in the popular Vampire of Siam series. The story begins in Bangkok 1948, shortly after the end of WWII and the Japanese occupation of Siam. The vampire, Ramonne Delacroix becomes involved in a quest for a mysterious artifact, - The Oracle - hidden during the war by the Japanese. He joins forces with the famous American Expat Jim Thompson, (before he was the Silk King he was an OSS agent) and together they do battle with the nefarious Japanese Black Dragons.