Except, of course, the doctor who prescribed them for you. Most of the doctors were killed, of course, but their records were retained and in the hands of the government.
A guide we had over there was telling us about running across some soldiers back then, and they’d handed him a piece of paper to read something from. He’d heard just enough rumours at this stage to gather that if they saw he could read this thing it might be enough to show them he was educated and put him in danger. So when they handed it to him, he just held it upside down and stared at it and after a short while they let him pass. Must have been a scary place to be around then…
The Tuol Sleng prison is a seriously heavy place to visit though (and possibly a strange place to have visited on your honeymoon 
), but well worth doing. He deserves life (though, practically the sentence may amount to that anyway).
Killing Fields was also a very creepy place. I remember a tree which just had a few nails sticking partway out of one section of the trunk, with a sign on it saying “Killing tree against which executioners beat children” (and had seen a drawn picture somewhere else of someone holding a kid by the leg and swinging against the tree…)
And following along on this, four top Khmer Rouge cadres were just charged with war crimes. About time!