http://necrometrics.com/tyrants.htm
And there are monsters like Leopold II of Belgium (possible victims in the range 2-15 million) who hardly anyone remembers:
http://en.wikipedia.org/wiki/Leopold_II_of_Belgium#Exploitat...
Actually, as hardly anyone remembers Leopold II maybe he is the ideal target.... :-|
[NB I eventually remembered that I'm against the death penalty - so what I am actually in favor of is apprehending the relevant individuals and bringing them back to face trial by the appropriate authorities. Although I admit there would be a distinct temptation to do a Cheradenine Zakalwe with Vasili Blokhin:
http://en.wikipedia.org/wiki/Vasili_Blokhin
Where was the Grey Area when we needed it!]