Pol Pot's reputation as one of the great killers of the 20th century is secure. "One of the most monstrous tyrants of modern times," was the verdict of his biographer, David Chandler.
Certainly Pol Pot was responsible for fewer deaths than Hitler, Stalin or Mao, who presided over regimes which directly or indirectly killed tens of millions.
But Pol Pot had so much less to work with - Cambodia had just seven or eight million people when his regime came to power. Yet in four years, from 1975 to 1979, he managed to kill perhaps 20 per cent of them.
The estimates have varied - one million to three million deaths has been a common range - but Dr Steve Heder, lecturer in politics at London's School of Oriental and African Studies, says the true figure was probably 1.7 million.
The US-government funded Cambodia Genocide Programme at Yale University agrees with this figure.
Pol Pot's connection with the deaths varied, since most were not direct murders but deaths resulting from the Khmer Rouge's disastrous policies, which turned the country into one vast agrarian labour camp.
But Dr Heder had no doubt that the blame could be pinned on the man who died on Wednesday night, aged 73. "In his absence none of this would have happened," he said.
Prof Douglas Pike, of the University of California, wrote last year that the phenomenon of the Khmer Rouge would probably never be explained.
"As with the other major unbelievable acts of inhumanity - Hitler and six million Jews, Stalin and 10 million kulaks, Mao and 15 million landlords - we can search but we will never find an answer to the question, Why?"
Dr Heder estimates that 600,000 or more Cambodians were directly executed.
"Of the 1.7 million deaths, something more than one third were executions," he said, adding that the rest were caused by starvation or disease.
Pol Pot's culpability through his personal control over the Kampuchean People's Republic is hardly in doubt. Dr Heder said the executions themselves maintained his authority, until he fled from an invading Vietnamese army in 1979.
Although millions died in China under Mao Zedong's brand of communism, Dr Heder said Pol Pot's ideology was more extreme - attempting to abolish private property and to destroy any distinction between rural and city workers. The many doubters were executed. The extreme policies destroyed the economy, leading to starvation and endemic disease.
Reviewing the carnage and defending comparisons with Hitler, author Anthony Paul simply reached for a dictionary definition of "monster" to describe Pol Pot: "a person of inhuman and horrible cruelty, an atrocious example of evil."
Three Asian gang members were found guilty yesterday of murdering actor Haing Ngor, who survived the "killing fields" of Cambodia only to be shot dead in a Los Angeles robbery. Tak Tan (21), Jason Chan (20) and Indra Lim (21) were convicted of first-degree murder for the February 25th, 1996, killing.
Ngor (55), a former gynecologist who won an Oscar for his supporting role in the 1984 film The Killing Fields, fled Cambodia in 1980 and settled in Los Angeles, where he devoted his life to helping Cambodians. In the film, Ngor played his friend, photojournalist Dith Pran, who also fled Cambodia and joined the New York Times.