Each new mass grave produces some extra helping of wickedness, some tiny, incremental addition to cruelty. In the oven-grey desert west of the Tigris yesterday, it was a gleaming steel rod amid a heap of brown bones and a rag of cheap cloth that symbolised Saddam's rule: a hip replacement. A gravedigger gently tapped at the leg of the decomposing corpse beside it; there was a ghostly, hollow sound. The murdered man had a wooden leg. On the day of their death, these people were hospital patients.
Body number 73 - they are numbered by the diggers according to the chronology of their discovery - even had a hospital tag still tied to a bone. If they still had their identity papers - and Saddam's executioners seemed to care little about such matters - their names were written in crayon on to the white shrouds in which their remains were wrapped. Thus these men's lives were revealed in a stranger's hand.
"Abdul Jalil Kamel Badr" was written on one small heap of bones, hair and decaying flesh. "Student at Kufa University Educational College - Arts Department."
In their white shrouds, more than 80 of them lay like dead sheep, under the midday sun. Others were lined in rows, 470 at the latest count, in the school basketball stadium back in Mutayeb, the scruffy little town on the Tigris where, 12 years ago, Shia Muslims to a man, they all obeyed the order of Hussein Kamel, Saddam's son-in-law, to assemble for a "meeting". Every man over 17 had to be there, and the few women who watched them gather in their thousands said that at least 40 lorries were waiting for them on the first night, 5 March 1991. The Muslim Shia intifada against Saddam - assiduously encouraged by George Bush senior after the liberation of Kuwait - had just been crushed. The executioners were already waiting at the desert killing fields at Joufer Safa. The name means "beach of rocks".
Many of the just-discovered dead still had their hands - or some hand bones - tied behind their backs. Ahmed Kadum Rassoul had been bound in this way. So had Rada Mohamed Hamza from Hilla, and Ali Hassouni Alwan and Ibrahim Abdul Sadr. So had the unidentified male "wearing dark green military clothing and shoulder patches" who was obviously a deserter from the army who had taken arms for the Shia uprising.
"There are many other sites all round here," a farmer, who was helping in the excavation, told me wearily. "Some of us heard the shots at the time and saw the bulldozer. It was very 'ordered', very routine. We were told that if anyone spoke of it, they would immediately be shot." He pointed to patches of disturbed land to the south - you could see the revetments left by the bulldozers once the deeds were done - and it was only then that the truth became obvious. There were thousands murdered here. Once a mass grave was closed, Saddam's killers simply dug another one.
You imagine a neat hole in the back of the skull. But as the Iraqi villagers in the grave pit brushed away at the grey desert soil yesterday, the heads that emerged were cracked, the bullet having broken open each skull. Nor did the earth always give up its dead so willingly. One gravedigger tugged for minutes with a great rock until it suddenly came away and a skull with dark hair and a shirt with bones spilling from it, sprang towards him.
A clutch of American soldiers, a US Rangers officer, two British forensic scientists and a bossy man from USAid were watching the exhumations. The soil was littered with cheap plastic sandals and sometimes little tufts of hair, like a child's curls on the floor of a barber's shop. Many of the bodies were in dishdash white domestic robes, the clothes they must have been wearing when they were ordered from their homes.
Another corpse had a wristwatch whose date had stopped at 9 March; it had resolutely ticked away on its dead owner's wrist for another five days in the earth.
But mass graves are political as well as criminal affairs. Hussein Kamel, Saddam's son-in-law - the man who ordered this slaughter - is the same Hussein Kamel who fled to Jordan and gave away Iraq's chemical weapons secrets.
Before he was lured back to Iraq - to be murdered, of course, by Saddam - Kamel talked to the CIA about Iraq's chemical weapons. Did he talk about this too, about the desert killing fields, about the fate of the men of Mutayeb?
In the children's stadium, the shrouds lay in military lines. Just over 170 had been positively identified. "These people are the victims of Saddam," Riad Abdul Emir, one of the mass grave investigators, said as he walked slowly along the rows of dead.
"But they are also victims of the Arab regimes who co-operated with Saddam, and of the West which supported him - because our 1991 intifada could have succeeded were it not for the interference of the American administration. They let Saddam do this, because it was in their interests at the time."
The presence of eight Egyptian bodies - apparently truck drivers working in Iraq who may have tried to fight on the Shia side or merely been freed from prison in the initial days of the uprising - suggested that other foreigners may soon be found.
Where, for example, are the more than 600 Kuwaiti prisoners who never returned from Iraq in 1991?
Mohamed Ahmed was vainly searching through the corpses for his brother's remains. "These dead people had rights," he said. "But how can we ensure that they get their rights?"Reuse content