A Chankiri tree, or Killing Tree, at the Choeung Ek Genocidal Center near Phnom Penh, Cambodia. Nearly 1.4 million people are estimated to have been killed and buried at Choeung Ek and other Killing Fields under the Khmer Rouge regime of 1975 to 1979. To save ammunition, the victims were generally bludgeoned to death or had their throats slit. At Choeung Ek, the executioners killed small children and infants by smashing their heads against this tree. March 1, 2012.