Kambutso is a typical African village of stick-framed huts plastered with mud set on a grass-covered hill in the east of the Democratic Republic of Congo. On a clear day you can see the sparkling waters of Lake Albert to the east and the thick rain forest that covers the Ituri region to the west. When I visited in August 2006, a dark cloud loomed as wisps of mountain mist wreathed the banana groves and mango trees.

In less restless times it might have been a beautiful place to relax for a few days, but I was there to meet a notorious Congolese warlord, Mathieu Ngudjolo Tchui, a powerful military leader and veteran of ethnic fighting that had convulsed the region. He claimed to command 10,000 fighters and was head of one of the last rebel militias there.

I wanted to ask him about the recent elections in Congo, about an amnesty agreement that he'd signed with the government, and about the atrocities attributed to him and his fighters.

Human rights activists had told me of attacks on villages by Mr. Ngudjolo's ethnic Lendu militia in which scores were killed (bodies mutilated and dumped in latrines), girls raped, children abducted into rebel ranks, churches burned, and hospitals turned into slaughterhouses. And, in Ituri, it was alleged that Lendu and other fighters used cannibalism to terrorize civilians who'd become inured to violent death during the war.

Some of these accusations would become the basis of International Criminal Court (ICC) charges for which Ngudjolo was arrested last week.

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At sunrise we set out from Bunia, a small, dusty garrison town where blue-helmeted UN peacekeepers peered from behind piles of sandbags topped with barbed-wire, armored personnel carriers trained their heavy machine guns down the main roads, and Humvees patrolled.

Our four-wheel drive wound its way up a rocky track into the hills, taking more than an hour to travel the 10-miles up an escarpment overgrown with elephant grass and scattered with grey boulders. As we rounded a corner, a dozen skinny stick figures appeared silhouetted on the road clutching AK-47s, heavy machine guns, and rocket launchers. Dressed in a motley collection of tracksuits, shorts, flip-flops, and T-shirts, they formed exactly the kind of roadblock you don't want to run into in Congo. Beside me, my translator Marrion P'Udongo, an evangelical pastor who makes a little money helping foreign reporters meet the people they want to see, smiled nervously, announcing, "We are here."

What did I imagine Ngudjolo might be? Perhaps an inhuman moral blank? Or an unhinged lunatic, passionate and quick to anger? Certainly I didn't expect the softspoken former Red Cross medical assistant and father of three who met me. He sat on a wooden chair, while outside his fighters relaxed by smoking cigarettes and fiddling with their guns. He was smartly dressed in civilian clothes and had neatly cropped hair. He was short and stocky with a pugnacious face and strangely tiny feet.

Ngudjolo spoke in Lingala, and Pastor Marrion translated for me. We discussed the recent elections (which would go to a second round vote before President Joseph Kabila was announced the winner), his childhood as a poor farmer's son, and his early schooling.

Born around 1970, Ngudjolo grew up during a period when coexistence between Lendu farmers and Hema cattleherders was punctuated by violence as populations grew and land disputes became frequent. A legacy of Belgian colonialism, this ethnic division, as in Rwanda between Hutu and Tutsi, was increasingly bloody.

Later Ngudjolo talked enthusiastically of the recent amnesty deal he'd signed and how, as a result, he looked forward to being integrated into the national army as a colonel. It was a role he believed he was well equipped for after four years of fighting against rival militias in Ituri.

He was disconcertingly reasonable, speaking with a calm, even tone, but looked awkwardly stiff in his chair, ill at ease with being interviewed.

As we talked, I grew increasingly nervous. It's one thing to ask a man about his upbringing or politics, it's another to come to a rebel's stronghold and question him about massacres he is accused of.

Ngudjolo leaned back in his chair and listened, hands clasped in his lap, head cocked to one side. Then, with palms upturned in a universal sign of innocence, he said that when there is fighting, of course civilians die and are displaced from their homes. He said that he simply defended his people, Lendu farmers, from attacks by cattleherding Hema militias. He denied having child soldiers, despite the hairless faces and slight shoulders of those standing guard outside the hut. Rape is so prevalent in Congo that he didn't bother to address the issue.

He showed no fear of either local or international justice. "I cannot fear international justice because for what can I be arrested? I have created a political movement," he said recasting his ethnic militia as a political force protecting his people's rights. An aide dressed like a Hollywood bad guy in a shiny tracksuit and dark glasses added with a smile: "In Congo we have so many criminals, we can't just talk about the militia leaders. If [the world wants] justice they must arrest the whole of the Congo!"

Ngudjolo's confidence was misplaced: the Congolese government has acted on an arrest warrant issued by the ICC. He was seized in the capital, Kinshasa, on Feb. 6 and transferred to The Hague, where he'll be tried on six counts of war crimes and three of crimes against humanity. He joins his comrade Germain "Simba" Katanga and their archenemy Thomas Lubanga Dyilo in the holding cells.

Ngudjolo didn't seem destined to become an international war criminal. He had an inauspicious career in the Army serving as a lowly corporal during the last years of President Mobutu Sese Seko before deserting in 1996. Quiet years followed during which he worked as a Red Cross nurse in Bunia, pushing gurneys and ferrying drugs between clinics. War broke out in 1998, but he didn't decide to join it until 2002 when the Union of Congolese Patriots, an ethnic militia of Hema pastoralists led by Mr. Lubanga, overran Bunia. Ngudjolo felt he had no choice but to fight.

Being better educated than most and willing to get his hands dirty, he rose quickly to lead an ethnic Lendu militia unsuitably named the Front for National Integration and formulated its military strategy, such as it was, employing tactics with which the war was already being fought: the targeting of both civilians and combatants with extreme violence.

He is being tried for an attack on the village of Bogoro in February 2003. More than 200 civilians died in the rout of a rival militia – one of the almost weekly massacres that took place between 2002 and 2004.

The attack was swift and brutal, according to United Nations investigators. At 5.30 a.m. hundreds of men, women, and children armed with machetes, spears, arrows, light machine guns, rocket-propelled grenades, and mortars surrounded the village; dozens who had sheltered in a school were shot or hacked to death with machetes, others were burned alive in their homes. Survivors were beaten and locked in a room with corpses, women and girls were raped and kidnapped. As the village burned around them, Ngudjolo and Mr. Katanga celebrated their victory.

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At the end of the interview, Ngudjolo stood and we shook hands. He gave a rare smile, telling me, "Most people would be too afraid to come to see us here in our home." I couldn't tell if this was meant as a threat or a compliment.

As we drove out of the village, Ngudjolo stood in the clearing at the center of Kambutso, hands by his sides. A few of his young fighters waved.