Stalin

....2.4 million people deported to the Gulags for political crimes. There were also 40 million arrested for common crimes, some of whom were arrested for ideological reasons or simply on suspicion, often without any proof or confirmation of reality, of subversive activities or advocacy of capitalism. 4.3 million dead in concentration camps administered by the Gulag and in prison......... For a total of 8.5 million deaths caused by Stalin. Cit Wikipedia.