Bat Wing

Bat Wing is the first book of the Paul Harley detective series preceding Fire Tongue. It features Haitian voodoo, vampirism, and murder in central London showing the lengths people will go through for vengeance.
"It seems to be pretty certain" he said, "that this thing is the wing of a Desmodus or Vampire Bat. Now, according to our authority"--he touched a work which lay open on the other arm of his chair--"these are natives of tropical America, therefore the presence of a living vampire bat in Surrey is not to be anticipated. I am personally satisfied, however, that this unpleasant fragment has been preserved in some way."