“Vampires remain a myth because of the poor quality of documentation of their existence. The lack of credible investigations, starting in the Middle Ages and continuing until the present time, has provided vampires with a cloak of invisibility that still exists.”
In The Vampires among Us by Thaddeus Romans
In my research for The Vampires Among Us, I read numerous copies of actual reports of investigations of reported vampire beginning in the 1500s. As the vampiress, Nessa, said in Neil Benson's novel, Unholy Embrace, "It is not possible to examine a vampire after their existence is ended because they rapidly decline into dust." The eroticization of the vampire occurred because when bodies were exhumed shortly after death, men had erections. This is a normal process that wasn't understood during those times. The quality of these reports were poor not just because of insufficient scientific knowledge, but because they were frequently conducted in a climate of hysteria. Someone would claim they saw the dead man walking in at night, and others would verify that false observation. The civil servant called in to make the investigation was under pressure to write a report that mollified the concerned citizens.
Even today, with electron microscopes, nothing can be learned about the biological existence of the vampire. If a slice of skin were taken from a vampire, the microscope would show dead tissues. This would be useful only if a vampire allowing a movie to be taken of the entire process. It is inconceivable that any vampire would consent to this. Only when a vampire is captured "alive" and studied on film will more conclusive evidence be available. Until then the vampire resides between the greatness of belief and disbelief.