Iraq: Lieut Col Saad Jasim is reluctant to talk in the courtyard. He orders his men to bolt the metal door to his small office before he will agree to speak.
Outside the brick hut is a large walled compound in which dozens of his armed troops from the Iraqi Civil Defence Corps are barking orders to each other in the bright morning sun. Between them and Fallujah's main high street is a vast concrete blast wall, guarded by a handful of extremely anxious defence corps soldiers.
It was on the other side of this wall and just a few minutes drive up the road that insurgents gunned down four American security contractors as they drove past in their four-wheel-drives on Wednesday morning.
Where there are now two blackened circles on the carriageway, a jeering mob quickly formed, dragged the burnt bodies from the cars and hacked them apart, pulling some through the streets from the back of a car, hanging others from the green metal pontoon bridge over the Euphrates.
It was the most gruesome attack against Americans in Iraq since the war last year and a horror whose images clash conspicuously with US talk of progress and rebuilding. None of the town's 900 defence corps went to intervene, nor did the Iraqi police, whose headquarters is even closer, nor did the thousands of US Marines based on the outskirts of the town.
"We were only told about it when it had finished," Lieut Col Jasim, (38), a former Iraqi army officer, offered by way of explanation.
"By the time we arrived there was no one there." It should come as no surprise that the Iraqi security forces in Fallujah are scared half to death.
This Sunni town, 40 miles west of Baghdad, has produced the most violent resistance to America's occupation of Iraq. There have been dozens of fatal attacks on US troops and Iraqi police, who are regarded by many locals as collaborators. In turn, dozens more Iraqi civilians have died in American raids and military operations.
Six weeks ago a gang of well-armed insurgents rampaged through Lieut Col Jasim's base and the nearby police station, killing 23 people and releasing dozens of prisoners. In front of his men, Lieut Col Jasim continues to insist that security is good here.
"There is no town or city that is empty of insurgents or criminals," he said. "We are passing through a stage where there is no central state and where no one is dealing with law and order. If the Americans deliver real authority to the Iraqis then no one will have an excuse to make operations against them."
Yesterday a joint police and defence corps team were manning a barbed-wire checkpoint on the edge of town and simply waving most cars through. There was no sign of American marines in the city.
Few in Fallujah will dare to criticise the muqawama, or resistance, yet yesterday even some in this town appeared shocked, if not by the killings themselves, then at least by the brutality of the mob.
"That was wrong. It was a mistake, it was against the Islamic Sharia," said Ghazia Mohammed, a school teacher queuing at a stationery store in the town centre. Yet even educated, middle-class men like this are deeply angry with the US occupation.
"It is not just a matter of resistance, it is a matter of self-defence because they occupied our state and we should dismiss them," he said.
"They destroyed our houses, our stores, they are raiding our families, they don't respect us. How should we accept that?"
Abbas al-Hussein, a strident, English-speaking civil servant from Fallujah's education directorate, spoke with foreboding about the future. "Anything could happen in this city from now on," he said. The people feel such injustice. The coalition forces have humiliated people and treated them badly."
American officials in Baghdad insisted the attackers were a "restorationist" movement that wanted to reinstall Saddam Hussein.
"I don't believe they want Saddam back," said Lieut Col Jasim. "It is an Islamic movement. They are fighting to get the Americans out."
The gunmen who orchestrated Wednesday's attack disappeared once the four Americans had been killed. It was the crowd, and particularly a group of teenage men who dragged the bodies from the cars and mutilated them.
Unbroadcast television footage showed them driving through the streets, trailing a disfigured corpse from the back of a white car as they waved Kalashnikovs and posters of Sheikh Ahmed Yassin, the spiritual leader of Hamas assassinated by the Israelis.
It was an act committed by "human jackals", Mr Paul Bremer, the US administrator in Iraq, said. His staff insist this attack and others recently are merely an "uptick" in "localised" violence.
It is, however, ever harder for Iraqis to believe that these killings will not seriously derail reconstruction.
Yesterday a trade fair to be held in Baghdad next week - the largest business gathering since the war - was postponed indefinitely.
- (Guardian Service)