@ Hanna;
i remember my mother in the 1980's telling us about the Khmer Rouge (we we children then). So if she knew - living in a remote area of a remote country (then South West Africa) without any media access (no internet etc) then it could not have been so secret and people did know about them.
But yes, most people i know, know nothing about Cambodia and Khmer Rouge.
And I also cannot understand why the perpetrators were so shielded. Not sure who protected them; and not sure who supported them originally.
For sure is not many people cared about what happened there.
I read somewhere that only 12 people (12 single people) managed to survive Tuol Sleng