This was documented in the work of Austrian forensic psychiatrist Richard von Krafft-Ebing. Many medical publications concerning clinical vampirism can be found in the literature of forensic psychiatry, with the behavior being reported as an aspect of extraordinary violent crimes.
Richard von Krafft-Ebing documented this in his work. Many medical journals that cover clinical vampirism are found within forensic psychiatry literature, where such behaviors are considered to be aspects of severe criminal acts.