How did governments convince the perpetrators who were gulity of mass killings in WWII to do this work?

To some
extent, the governments involved in the mass killings ofdid not have to convince their people to
participate in those killings.  To the extent that they did have to convince them, it was done
through the use of propaganda and, to some degree, fear.

Some of the
perpetrators were motivated by long-standing hatreds that were not really caused by any
governmental body.  For example, there had been a long history of anti-Semitism in Germany (and
elsewhere) before...