Unholy Awakening — Michael Gregorio

A woman's body has been found at the bottom of a well. The death wounds are startling: two small, round punctures to the jugular vein. . . .
Vampire fever is spreading throughout the countryside, and suspicions soon fall on the recently arrived Emma Rimmele. Investigator Hanno Stiffeniis must do everything he can to find the true culprit before the mob's hysteria reaches its breaking point and turns violent.

Set in a nineteenth-century world where people truly believed in vampires, Unholy Awakening pits rational, scientific detection against unhindered, violent superstition.