" No one knows for shure what happened to them(MYANS), it is as if they EVAPORATED but some believe that they EVOLVED to a higher level of BEING/EXISTING and at a higher frequency and they are beyond our limited perceptions."
Pssst .... let me give you my take - A bigger and superior group of people fought them in a war, kicked their asses and killed them all.
If you call being killed and buried .... "EVAPORATED" so be it. As for the "higher frequency" maybe they were humming an AC/DC tune prior to thier being BEHEADED?? And yes death at present is "beyond our limited perceptions" as no one has returned to inform us of the AFTERLIFE!