Holy crap! Forty thousand sets of remains five years ago that can't be identified through conventional means?
Now, I can only assume they can identify the cause of death in most of those remains, but... Da-AMN!
Last statistics I saw said that something on the order if 50 thousand people disappear within the continental United States alone. The majority are never found.
Now, think about other societies and areas that do not live in our or Great Brutain's surveillance society. Think Africa, much if the Middle East, India, China, etc. Vampires could thrive in those places - or could they? Just last year China had to put down a "revolt" in one if it's western provinces. Could that have been a zombie outbreak? A cleverly- disguised vampire contagion? China is very, very good at covering up things in general. Just think what they'd do in the case if a real vampire or werewolf attack.
What about India? Are all those attacks by man-eating tigers really tigers at all?
And what about the famous lions in the 1800s in Africa? Surely two maneless male lions could not have killed nearly a hundred and fifty people. Was that a werewolf? Maybe those lions were scapegoated to cover up the real cause?