What do you ask a killer? That's the question as I sit down with An Myong-chol.
True, with his neat haircut, monogrammed shirt and beefy frame packed into an expensive double-breasted suit, An looks more like the bank clerk he currently is than a former guard at one of the world's most notorious prisons. But he outlines his old career in such stomach-churning detail that he leaves little room for doubt.
From 1987 to 1994, An was a guard at camps in the Hoeryong area of North Korea after being chosen because of his family's elite background. Independent confirmation of how many are imprisoned in North Korea and under what conditions is difficult to come by, but Amnesty International believes "hundreds of thousands" of people are held in gulag-style camps.
An says the purpose of the camps is to detain "anti-government elements", getting inmates to make everything from bacon to amphetamines. He claims the children of families considered to be counter-revolutionary are incarcerated with their parents.
His description of life in the camps is graphic. Hard labour and small rations mean that within three months the weakest began to die. Eating "cockroaches, snakes and rats" to survive, at least a quarter of the inmates usually die. Beatings and killings are an "everyday affair", with inmates "treated like dogs or pigs". Many are deliberately crippled or blinded by torture, women are kept as sex slaves to officers, victims are buried in unmarked graves; weeping for the dead is forbidden, because "tears should not be wasted on anti-revolutionaries".
An's job was to stop people fleeing from the camps. He says he shot people "constantly", sometimes "two and three at a time" for trying to escape. "I was told the inmates were very bad people who had betrayed \ Kim Jong Il and their country, so I had no sense of guilt about this," he says. "But later I had the chance to talk to inmates, and I began to wonder if they really were that bad and why they were in prison."
Eventually, he says, his doubts became too much. He fled to South Korea, via China, and began life as a refugee. Now he is married with two children, has converted to Christianity and works in a Seoul bank. "All the things I've described still go on."
An is one of several high-profile escapees from the Pyongyang regime who have gone public about their previous lives; the most famous is Hwang Jang-yeop, former secretary of North Korea's Workers' Party, who defected in 1997.
On the victims' side is Kang Cheol-hwan, imprisoned in a camp aged nine, released a decade later, in 1987, and now a reporter for the South's largest newspaper, the Chosun Ilbo; and Kim Tae Jin, who met An Myong-chol while a prisoner in a North Korean concentration camp from 1988 to 1992 and who escaped to South Korea in 2001.
Today these men can often be found sitting side by side at press conferences, united, it seems, in their hatred for the government of the land they fled. Their testimony about one of the world's most closed societies has had a huge impact on perceptions of the Pyongyang regime.
It seems only fair, then, when the diplomatic knives are out for a designated member of the so-called Axis of Evil, to ask: can these people be trusted? No, says Choe Kwan Ik, editor of Pyongyang mouthpiece The People's Korea. "These people have been circulating for some time and are clearly in the pay of US and South Korean intelligence services who only want one thing: to isolate and destroy North Korea. They are being used."
Cheo would say that, so I try Shin Yoon-Seok of the Korea Times. Do Koreans believe the testimony of these men? "Basically, yes," he says. "Their stories are detailed and have been corroborated by other sources. There is no doubt the atrocities described by An Myong-chol go on in North Korea. Also, South Korean intelligence is in the business of détente these days, so they're unlikely to use them to attack Pyongyang."
But both Shin and Hazel Smith, a senior researcher with the UN's peace and governance programme, who has worked in North Korea, acknowledge that the defectors are being used by anti-Pyongyang forces. "It's in the interest of some groups to spread their stories around," says Smith.
What sort of groups? Well, for example, a Japanese right-wing organisation pushing for sanctions and military action against Pyongyang helped sponsor a trip to Japan by An, Kang and Kim. This doesn't mean that they are lying, just that the decision to speak out means having to breathe in the poisonous political atmosphere of a conflict that has gone on for more than half a century and which seems to be nearing some sort of climax.
What conclusions has An drawn from his experiences? Have they made him anti-violence? "I've concluded that the US must attack North Korea sooner rather than later, because there is no hope of a revolution there. People are too terrified. Economic sanctions would be good, but military action would be better."
But North Korea has a million-strong army, hundreds of aircraft, thousands of tanks, perhaps 500 ballistic missiles and, possibly, a nuclear weapon. Wouldn't it bring catastrophe? "No," says An. "Pyong-yang is bluffing. It is not capable of waging war. There is no fuel for tanks or the planes and no bread for the army. A war would be over in one day." It's a terrible risk. Can you be certain? "I'm certain."
David McNeill