A group of 15 fighters dressed in black and carrying an array of weapons ducked into a two-storey house in war-torn southern Fallujah yesterday morning. Their movement was picked up by an unmanned spy plane that beamed back live footage to a control centre on the edge of the city. Within minutes, an airstrike was called and the house disappeared in a giant plume of grey smoke.

From a house across the road, the explosion flushed out another group of guerrillas. Deafened by the blast, they stumbled out into the street, formed a ragged line and started off on the marathon to postpone their deaths, the drone dogging their every step.

“The rats are trying to move about,” Major Tim Karcher, of the Second Battalion, Seventh Cavalry, said as the figures flitted from street to street, seeking cover close to walls.

Sometimes they can throw off the drone, ducking out of sight of the men in whose power it is to summon FA18 fighter-bombers or 155mm artillery strikes. But they have no way of knowing. And, increasingly, as they run they are coming into the crosshairs of American snipers, crackshots such as Sergeant Marc Veen and his long-barrelled rifle, Lucille. Yesterday morning he spotted a black- clad man with an AK47 assault rifle peering round a corner 500 yards from the villa where Cougar Company of the Seventh Cavalry has set up a forward base.

He shot the man in the stomach: he fell, but kept crawling, so Sergeant Veen shot him again in the shoulder. Still the man tried to move away, so the sergeant blasted him with his 50-calibre machinegun.

“There’s pretty much no feeling,” the 24-year-old from Chicago explained, perched on the parapet of the house, the shell of the killer bullet tucked as a trophy into his flak jacket. “If I didn’t get that guy, that guy would get one of my buddies some time later.”

The battle for Fallujah is all but over. The main north-south road in the once-dreaded Jolan district is a US military highway. Any guerrilla who could make his way back up from the last pockets of resistance in the south would see the mujahidin graffiti — “Jihad, jihad, jihad, God is Greatest and Islam will win” — replaced by slogans daubed by the US-backed Iraqi Army, posted the length of the route.

Standing on a street reeking of decomposed bodies, the ruins of a five-floor building silhouetted behind him, Lieutenant Fares Ahmed Hassan said that the destroyed city would send a strong message to a nation where force has long been the lingua franca of government. “When the people of Fallujah come back and see their houses, they will kick out any terrorists. This will be an example to all Iraqi cities,” the Kurdish officer said.

Apart from a few women and children, the only civilians he had seen were men of fighting age, about 500, detained for vetting. He said that some civilians had said that insurgent snipers had shot anyone trying to leave their homes. As US troops sweep through the houses, they are unearthing the insurgents’ horrifying secrets — more akin to the handiwork of serial killers than guerrillas or even terrorists — that have shocked the world and explain why this offensive has met with so little opposition from the Arab world.

In the south of Fallujah yesterday, US Marines found the armless, legless body of a blonde woman, her throat slashed and her entrails cut out. Benjamin Finnell, a hospital apprentice with the US Navy Corps, said that she had been dead for a while, but at that location for only a day or two. The woman was wearing a blue dress; her face had been disfigured. It was unclear if the remains were the body of the Irish-born aid worker Margaret Hassan, 59, or of Teresa Borcz, 54, a Pole abducted two weeks ago. Both were married to Iraqis and held Iraqi citizenship; both were kidnapped in Baghdad last month.

US and Iraqi troops have discovered kidnappers’ lairs filled with corpses or emaciated prisoners half-mad with fear, and piles of bodies of men who had refused to fight with the insurgents. As the guerrillas run their last sprint from death, sympathy for their cause is running out among Iraqis.

• Barham Salih, Iraq’s interim Deputy Prime Minister, said in a newspaper interview that the country’s elections in January would depend on security. It was the first time a senior Iraqi politician had said that violence could derail the vote.

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