Vampire Bats Sucking Blood in Klineschloss or Vampires?
The setting is Klineschloss a small village where superstition rules. The village head honchos think vampires are attacking because villagers are found with puncture wounds and blood missing. Karl Brettschneider, the inspector, distrusts the villagers explanation, and Dr. Otto von Niemann is a scientist/doctor that aids the victims.
Using some literature Niemann informs the inspector of vampire cases. The inspector starts to think the answer could be preternatural after all. It requires some goading from Niemann for Brettschneider to come around to this consideration.
Herman Gleib Pursued by Villagers
After Martha Mueller, an apple vendor, is slain and drained. Herman Gleib is surmised as the killer. He is simple minded and likes bats. While some villagers pursue him, the real killer does in Georgiana; she is Dr. Von Niemann's housemaid. Ah, the villagers are wrong.
Tissue Needs Blood
Niemann who got the inspector to look for vampires is the actual rapscallion. He invented tissue that requires blood and has used his assistant to get it. Emil, under hypnosis goes out and retrieves villagers, and Niemann takes their blood to feed the tissue.
So, the inspector has been vindicated. His concept that no preternatural activity was involved was correct.