After reading this thread, I'm absolutely obsessed with this case and wondering if there are other victims. After a brief overview of his sickening rants on Quora, it's clear that he's been harbouring racist views for quite a while and that he's had some experiences as a kid growing up in South Africa that led to his deep anger and hatred of people of colour. It's very easy to see the jump from his white supremacist worldview to serial killing and rape, since it's all about power and domination.
I find it interesting that the two known victims had two different causes of death (shooting and strangulation) and I wonder why. Usually, with a serial killer, you have similar victimology and cause of death (in this case it's very clear the former is consistent but not the latter). Do his known crimes read as someone just getting started or a killer in his peak? Statistically, serial killers get started earlier in life (20s/30s) so, as previous commenters have noted, it wouldn't surprise me at all if there's some dark things to uncover from his life in SA - and in particular, from his time in the army. In one of his Quora responses, he said that he was sent into black communities to "protect" them during the apartheid. Who knows how accurate that is, but if true, it would mean he would've be in a position of power in vulnerable black communities. That scares me.
I also find it fascinating that the SD card was just lying in the street and that it was labelled so blatantly. I wonder if he himself dropped it - but then why would he have it on him in public? I wonder if it was indeed stolen when he reported his car broken into, and perhaps the thief found it, didn't want to turn it in themselves (because of their own crime) and so they labelled it and left it somewhere public so it would be discovered? Either way, imagine how he felt when he discovered it was missing... lol. I definitely take pleasure in knowing how much he must've freaked the eff out.