Most people would not recognise him now - he has a full and manly frame, and a puckish smile; he has even had his teeth fixed. But I would know it anywhere, from the mixture of mischief, a deep inward stare and that mop of hair. Sixteen summers ago next week, Fikret Alic was probably the most familiar figure in the world. His skeletal, emaciated torso and xylophone ribcage, behind the barbed wire at Trnopolje concentration camp, embodied the violence unleashed on Bosnia's Muslim civilians at the orders of Radovan Karadzic, the man due to be taken to The Hague this weekend to answer charges of genocide and crimes against humanity.

    As Karadzic awaits his fate, Fikret Alic is back in Bosnia. Although currently living in Sonderberg, Denmark, he has bought a flat in a block still under construction in Kozarac town centre, and is here to save money to rebuild the nearby family home out of which he was chased in 1992, having completed the foundations. The arrest of the man who organised his torments has left a bittersweet taste.

    "I am happy and I am angry," he says. "For 13 years, he was living protected as a free man. And for the three years before that, all the world knew what he was doing, from my camp to Srebrenica, but did nothing to stop him. So now the truth will be told, but what has happened to us all this time? Now at last I am happy just because I am alive and here, with my wife and children, and not dead like so many others. But while he was free, I was broken, too."

    I came across Fikret Alic in 1992 at the Trnopolje concentration camp, where I had gone at Karadzic's invitation, while trying to inspect the gulag of concentration camps he had set up across northwestern Bosnia - places of reputed mass murder, torture, mutilation and rape - all of which Karadzic denied, insisting: "See for yourself." We took up his suggestion and were directed down a seamless chain of command, first from Karadzic's doorstep to the gates of a place of horror called Omarska, then, after being bundled out before seeing too much, Trnopolje, where Fikret and others languished behind the wire. They had arrived that morning, he said then, from yet another camp, Keraterm, where during a single night 130 men had been massacred in a hangar. Fikret said he had been ordered to help load the bodies on to bulldozers, but, weeping, had his place taken by an older man.

    Now Fikret and I meet again, this time to celebrate the arrest of the man who orchestrated the most terrible days of his life. After the embrace, there's a hollow laugh and a pledge that next time we really must get together for another reason. We are talking in Fikret's native town of Kozarac, a place that the Bosnian Serb leader hoped to wipe from the map. As Karadzic languishes in Belgrade, Friday night is getting into gear, the fairground is grinding into action, children are whooping despite the rain; music is throbbing out of bars and cars on to the warm, wet streets and girls on heels like stilts strut into town. The boys' haircuts are stiff with gel and families of three generations are out for a stroll. It could be a libidinous seaside town in Southern Europe.

    Kozarac now calls itself "the biggest small town in the world." Yet 16 summers ago this week, when I came through here on Karadzic's authority, escorted by his guards, it had been burned to the ground and the stench of charred masonry was still heavy in the air. Its inhabitants - apart from a few Serbs tending their animals as though nothing had happened - were either dead, driven out, or taken to one of the gulag of concentration camps. There was no war here in the Prijedor region of Bosnia, just a sudden, vicious and brazen attempt to eradicate an entire population by killing, incarceration, rape and enforced deportation. According to the masterplan of which Karadzic is accused, all the people on these streets this Friday night, and in these rebuilt houses, were intended to be dead, gone or never born.

    But Kozarac has been rebuilt by the hard work and defiance of a diaspora, some of whom come back for the summer and others who have come back to live - albeit in the Serbian half of Bosnia, the so-called Republika Srpska. The mosques are rebuilt, too. As Edin Kararic, a truck driver living in Watford - an Omarska survivor who has opened the Mustang bar on the main street - said to me a few years ago: "It's not hard to get money for a mosque, but it is extremely hard work to get money to rebuild our houses. I don't go to the mosque, but I like it that they are here, because every minaret is a finger up to the people who tried to put us out. It says: We're back!"

    Every year now, there is a commemoration service at Omarska, making this the gathering of a unique tribe in Europe, Clan Omarska. This year's remembrance takes place next week. A local group called Izvor, formed by camp survivor Edin Ramulic, calculates that for all the thousands of bodies already uncovered 3,205 people are still unaccounted for.

    As the night unfolds around us, Fikret tells about the hunt in Trnopolje, after our visit, for anyone who talked to the press that day in 1992. He talks about how seven people had been killed for doing so, and how he had had to hide for 10 days after our meeting on 5 August, at which point he joined a convoy of deportees on a terrifying mountain exodus at gunpoint across no-man's land and into Muslim-held territory. Disguised as a woman he was saved from being taken into a group to be raped because he smelt so badly.

    Later in the conflict he had tried to fight in the remarkable 17 Krajiske Brigade, based in Travnik, made up of ethnically cleansed men and women from around Prijedor determined to go home. But he kept coughing up blood and was discharged.

    After living in Slovenia and Croatia he had a breakdown. "I was talking to a tree about my time in the camps. I might as well have been in a straitjacket." Then came a chance to go to Denmark, a meeting with a Bosnian woman from Sanski Most, near Kozarac, in 1999, "and when I woke up, I was married," he laughs. Work loading trucks at a slaughterhouse ended in 2000 after an accident in which a 200kg (32st) carcass fell on his back, but although he does not receive disability pension, the couple have clawed together the money to buy the lease on their flat in Kozarac, and are considering rebuilding the family home, which lies in a small hamlet, surrounded by other incinerated houses, a few returnees and their killers and torturers.

    Of his persecutors he now says: "No one has ever said sorry for what they did. I don't know what it is about these people - I can show you five killers any time we go to Prijedor. Either they are proud of what they did, or pretend it did not happen. I am waiting for someone to admit what they did, or apologise, but they do not, they never will. They have built a monument outside the camp where I was, but it is to Serbs who died, not us. I don't know of any Serbs who died there."

    The long road to Fikret, Trnopolje and Omarska - and to being back in Kozarac last week - began in London at the end of July 1992, when my colleague Maggie O'Kane and the American Roy Gutman published reports from fugitive deportees from Bosnia telling of beatings, torture and murder in the camps, among them Omarska - the place that would emerge as the second most deadly killing field in Bosnia's war, after Srebrenica.

    When he invited us to visit the camps, Karadzic greeted us with that professorial, wayward air and faux academic veneer that belied his deranged vision, but left no doubts about his authority over Omarska, promising that we would enter the camp on his word. He sent us down the chain of command to Omarska, first to his Deputy President, Nikola Koljevic, who would be our supervisor, then the crisis staff of the nearest town and administrative centre for Omarska, Prijedor. On the way there we passed the incinerated ruins of Kozarac - "They are the people who fled because they would not accept the peace," said our escort, Colonel Milan Milutinovic of the Bosnian Serb army.

    After hours of obfuscation and failed attempts by the committee to take us to other camps that had already been inspected by the Red Cross, we set out for Omarska, eventually passing through the back gates of the camp and into another world.

    A column of 30 men emerged blinking into the sunlight from the depths of a hangar. They were in various states of decay, some skeletal, with shaven heads. They drilled across a tarmac piste under the watchful eye of a machine-gunner and into a 'canteen', where they gulped down watery bean soup like famished dogs, keeping their bread roll for later. They were told they were allowed to speak freely, but they clearly dared not, the guards swinging their guns; there are few things like the burning eyes of a prisoner who dare not speak what he yearns to say. One man, Dzemal Partusic, said only: "I do not want to tell any lies, but I cannot tell the truth." Another, Serif Velic, replied when I asked him about a wound to his head, that he had fallen - it had happened naturally.

    When we tried to get to the hangar in which the prisoners were held, we were stopped by the commandant and Prijedor's chief of police, Simo Drjlaca, cocking their guns. Time, and subsequent trials at The Hague, would tell what Karadzic wanted to hide - a nightmare of killing, torture, mutilation, starvation, drunken sadism and rape.

    Like Alic, Serif Velic also joined the 17 Krajiske "ethnically cleansed" brigade after suffering in the camps. This week, he, too, was back in Kozarac, living next to a stone marking a mass grave of 456 bodies in the nearby village of Kevljani, and pointing out another likely mass grave in the field behind his house, where the vegetation becomes suddenly uncomfortably lush.

    "I was happier about the rain on my lawn than about the arrest of Karadzic," he says. "It's too little, too late. I have taught myself not to hate, because if I hate, that is yet another burden on my back. I want justice, but not revenge - I just want my soul to be in peace. But I cannot forgive. How can I forgive someone who shows no remorse, like Karadzic and all the little Karadzics around here who did these things to us? How can I forgive things that were done by people who are proud of doing it, would do it again and do not ask my forgiveness?"

    By the end of the war, Radovan Karadzic had for three years had his hand clasped by the leaders of the Western world, as a fellow politician and diplomat. Then, suddenly, after his indictment by the newly established Hague tribunal, he became a wanted war criminal. But while our journey to the camps had taken us down the chain of command from Karadzic to Omarska over four days, The Hague's long road to Karadzic worked the other way round over 13 years, beginning with the minnows.

    In 1996, while 60,000 foreign troops patrolled Bosnia, the fugitive Karadzic moved openly between his home in Pale and the Prijedor area. The first man to be arrested and delivered to the tribunal was Dusko Tadic, a parish-pump sadist from Kozarac, who had kept a cafe called Tibet.

    Tadic had toured the camps to kill and rape at leisure, and became The Hague's first conviction, in May 1997. I had not known him, and testified as an expert witness. But I was curious about the people I had met; much was known about Karadzic by now, but not his middle management, the people we had met that day along the chain of command, on our way into Omarska. I found Deputy President Koljevic in Banja Luka; he had been a mid-ranking Shakespeare scholar before going into politics with Karadzic, but was now mumbling into his cigar about "digging up the bones, we were digging up the bones" - though it was not clear which bones.

    So, finally, in court at The Hague, the story of Karadzic's camps began to be told. Now Mark Harmon and Alan Tieger, the two remarkable Americans who prosecuted Dusko Tadic at the outset, are due to bring the case against Karadzic.

    The survivors' campaign for a memorial at Omarska - which is now owned by steel magnate Lakshmi Mittal, and produces 1.5 million tonnes of iron ore a year - is four years old, led by Satko Mujagic, a survivor living in Leiden, the Netherlands. Satko's foundation, Optimisti 2004, has been building sports and communal facilities in Kozarac, and he is back this week to inaugurate a gym with 49,000 euros given by wellwishers and what Satko believes to be the first and only donation ever made by the Serbian authorities to a returnee project, of 15,000 euros.

    "It is one thing, and a good thing, to arrest the man, Karadzic," he says. "He was the big war criminal, the man with the idea for all that happened. But it is another thing to arrest the idea. Karadzic's ideas live on in the existence of Republika Srpska, and if this is all about joining the European Union, for the Republika Srpska to join the EU would be like Europe admitting a part of Germany that still agreed with Hitler, just because it is in Europe. I have rebuilt the house you are staying in now, but in 1992 it was burned while my grandmother was inside - she is one of the 3,205 people still missing - and I was taken to Omarska. No one has ever said sorry for what they did, no one has ever helped us to return and the authorities oppose outright any monument in Omarska to what they did."

    I remember Satko playing ball with his little girl against the wall of the cells where he was kept in Omarska during a visit when she was two years old. Now she is six, and Satko says: "When I told Lejla that Karadzic had been arrested, she said that if he killed more than one man, he should go to prison for life, but in prison should not be starved like her father - no one should do that."

    Dzemal Partusic - the man who had not wanted to tell any lies, but could not tell the truth in the Omarska canteen in 1992 - has also rebuilt his home here, on a hillside in Kozarac. In the week of Karadzic's arrest, he is free and happy to talk as he feels.

    "It is important that Karadzic has been arrested," he says, above a beautiful view stretching towards Omarska. "I see him as a second Hitler, the person who thought he could do whatever he wanted to us, and did. He was a man the world negotiated with, but I saw him as a man you cannot negotiate with. So that is good. But what are we left with?

    "We can build our houses, we can show them we are back, that this is our country, but we can never get back our lives as they were before. Karadzic being arrested will not give us back our dead."

    Eventually Fikret Alic and I take a drive out of flourishing Kozarac to the hamlet where he grew up and from which he fled into the mountains, only to be captured - while most of his friends were killed. "We found parts of their remains later," he says. We stop at a mosque, where a plaque names the hundreds of dead from just that tiny neighbourhood. "That is my brother," he says, "and that my grandfather." We drive on, past the rebuilt houses, to the cement foundations of what Fikret hopes will one day be his home again, and where he and his mother, sisters, wife and their children were yesterday due to cook a lamb barbecue. I praise the whole, defiant miracle of Kozarac. "Oh," counsels Fikret in reply, "it is not a problem to build a house. It is more of a problem to awake a dead man."