Thats stretching it dont you think...
Mao Ze-Dong (China, 1958-61 and 1966-69, Tibet 1949-50) 49-78,000,000
Jozef Stalin (USSR, 1932-39) 23,000,000 (the purges plus Ukraine's famine)
Adolf Hitler (Germany, 1939-1945) 12,000,000 (concentration camps and civilians WWII)
Hideki Tojo (Japan...