About 300,000 people have died and 2.7m people have been displaced
In late 2007 I was in a large and overcrowded camp for displaced people just outside the western Darfur town of El Fasher.
A young mother, her face wet with tears, told me the story of how she came to be there.
"It was six in the morning when we heard the sounds of airplanes, horses and camels," she said.
"Then came gunfire. We were very frightened and stayed in our homes. After a while some men with guns arrived in the village and told us it was safe to come out. There were nine people in our house, including my son and my brother.
"The gumen told them to lie down. Then they shot them all. The men took everything. They even took my clothes and left me naked."
Khadiga Osman says Sudanese government soldiers helped the Janjaweed Arab militia carry out the massacre. "I saw their uniforms clearly," she told me.
Many others in Darfur said the same.
But given the Sudanese government's repeated denials that their soldiers backed or helped the Janjaweed carry out atrocities, the allegations have long been hard to prove.
They said they are the ones who help the rebels and you have to kill everybody. Don't leave anybody, just kill everybody
Yet now a former Sudanese soldier has claimed that his regiment, based near the town of El Fasher, joined Janjaweed fighters in seven attacks on villages from late 2002.
Khalid, which is not his real name, says he was forcibly recruited and then left in no doubt what officers wanted him and his fellow black conscripts to do.
"The orders given to us are to burn the villages completely. We don't have to leave anything, even the water pots we have to destroy. We even have to poison the water wells.
"We were also given an order to kill all the women and rape the girls under 13 and 14 downwards."
He confirmed he was ordered to rape and kill adults and children.
Khalid admits to taking part in burning peoples' homes but insisted that he had no choice because he had seen two other conscripts of black African origin shot dead after refusing to do what they were told.
But he says he always tried to shoot over people's heads and merely simulated the rape of a young women that he was ordered to violate.
I asked Khalid what orders he was given about what to do with unarmed civilians who offered no resistance.
"They said they are the ones who help the rebels and you have to kill everybody. Don't leave anybody, just kill everybody."
Khalid said he was also told to shoot children that had been left behind by their parents.
Mike Thomson has reported for years on Sudan's conflict
He estimates that the number of civilian killings he witnessed by Janjaweed and government troops runs into more than 1,000.
Finally, after a year's service, he deserted from the army and later managed to get out of the country.
Fearful that members of the International Criminal Court might come knocking on his door with an arrest warrant, Khalid asked me not to reveal his name or the place where he now lives.
But he insists that the blame for all that happened lies not with him, but with the President of Sudan, Omar Al-Bashir.
"Omar Bashir is in the chair. All information comes from him. The responsibility is down to him. He is the first person that is responsible for the genocide, of the killing of the children, of everything.
"If you are head of the country then any crimes then you are responsible for any crimes done by your soldiers. It is al-Bashir doing all these things."
'We were ordered to kill all the women'
Should judges from the International Criminal Court come to the same decision, which it is widely expected that they will, a warrant will be issued for the arrest of the Sudanese President.
He is currently accused of war crimes, crimes against humanity and genocide.
However, responsibility for the execution of a warrant for some, or all of these charges, will be left to the Sudanese authorities.
So far they have refused repeatedly to hand over two other Sudanese officials also wanted by the ICC.
As a result nobody should expect to see Mr al-Bashir standing trial in the Hague any time soon.
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