In Britain, the chief of the defence staff, Air Chief Marshal Sir Jock Stirrup, said yesterday that the “appalling” reports of the massacre could undermine British support for the war. “This sort of accusation does make that harder to achieve,” he said.
The pictures of the dead, which are being closely guarded by the US naval criminal investigation service, were taken by a military photographer who is believed to have arrived on the scene moments after the shootings.
Many American forces are accompanied by photographers to gather intelligence and to shield soldiers from false accusations of torture, intimidation and violence. In this case, the evidence points fatefully to a murder spree by marines.
The stain on the American military could prove harder to erase than the photographs of sadistic prisoner abuse at Abu Ghraib.
Comparisons are being made to the My Lai massacre in 1968 in Vietnam, in which American soldiers slaughtered up to 500 villagers.
Up to a dozen marines may face criminal charges including murder, which carries the death penalty, dereliction of duty and filing a false report. Three marine commanders were suspended last month.
The naval inquiry is focusing on the actions of a sergeant who may have been the leader of a four-man “fire team”.
Miguel Terrazas, 20, a lance-corporal from El Paso, Texas, was travelling in a convoy of four Humvees in Haditha just after 7am on November 19 last year when a roadside bomb struck his vehicle, killing him and wounding two others.
The events that followed are the subject of two military inquiries due to report soon: one into the facts, the other into a cover-up.
One witness, Aws Fahmi, heard his neighbour, Yunis Salim Khafif, plead for his life in English, shouting: “I am a friend, I am good.”
“But they killed him, his wife and daughters,” Fahmi said.
It is clear the marines lied by blaming the deaths of 15 civilians on the roadside bomb and alleging that a further eight Iraqis were insurgents who died in a gun battle.
Asked last week how many Iraqis were killed by the roadside bomb, a Pentagon official said: “Zero.” The marines never came under hostile fire, a spokesman added.
Investigators have established that the killings unfolded over three to five hours. “This was not a burst of fire, but a sustained operation,” a Pentagon official said.
The Sunday Times has reconstructed the events with the help of Abdul Rahman al-Mashandani, of the Hammourabi human rights group in Iraq. It appears the first killings took place when a taxi carrying four students pulled up at a checkpoint set up by the marines.
Abu Makram, 50, had been awakened by the roadside bomb and watched from his window as the terror unfolded. The car’s occupants were all ordered out and shot.
The marines then stormed three nearby houses. “They blew open the front door of the first house,” Makram recalled, “Once they were inside, we heard another explosion followed by a hail of gunfire.”
It was the home of 76-year-old Abdul Hameed Ali Hassan, whose leg had been amputated because of diabetes. “He was a blind old man in a wheelchair,” Makram said.
Hassan’s granddaughter, Iman Waleed, 10, was in her nightclothes. “About 10 marines entered the house,” she said. “They threw hand grenades and began firing in all directions. Grandpa was sitting close to the hall and they shot him dead.”
In a nearby room, her father was reading the Koran. “The American soldiers went into the room and killed him too,” Iman said. “They gathered all of us into one room my grandma, my mama, my brothers and my uncles. They threw in two handgrenades and started shooting at us.”
The adults tried to protect the children with their bodies, but were slain. When Iman dared to look, she saw that “everyone was dead around me except for my brother and my uncle”.
Both were injured and Iman was hurt in the leg. The rest of the family, including her brother, Abdullah, 4, died.
Iman fled next-door, where her other grandfather Yunis lived, only to find everybody there appeared to have been killed too. There was in fact one survivor, Safa Yunis Salim, 12.
“My daddy tried to open the door to let the Americans in, but he was immediately shot in the head and body,” Safa said.
“I managed to hide under the body of my brother Mohammed. His blood covered me and protected me as I pretended to be dead.” They also killed her four sisters including Aysha, 4, and Zainab, 2.
Five hours passed before Safa managed to escape. “I was the only one who survived. I watched them kill my entire family. I am all alone now,” she said, crying.
When the marines stormed the third house they changed tactics. The men were separated from the women and stuffed into a large cupboard, according to Yussef Ayed Ahmad, the brother of the dead men, who lived next-door.
“They placed my four brothers into the wardrobe and proceeded to shoot them as they were inside,” he said. “My mother and sister told me later how they died.”
The marines found an AK 47 in the house the only gun found in all three homes but there is no evidence it was fired.
The marines’ cover story quickly began to unravel. In March, Time magazine revealed the existence of a video shot the day after the attack by an Iraqi student journalist. It showed the victims still in their nightclothes, a trail of blood and shrapnel and bullet marks on the walls.
At the local morgue Waleed al Obeidi, who received the corpses 24 hours after the killings, also disputed the marines’ account. “Two bodies were completely charred,” he said. “The others, including women and children, had all been shot at close range.”
According to some reports, American warplanes dropped 500lb bombs on the houses.
The marines paid $2,500 (£1,350) in compensation for each of the 15 victims who were shot in their homes. They refused to pay for the four brothers and five occupants of the taxi, claiming they were insurgents. Officials now say those men were innocent.
General Michael Hagee, the US Marine Corps commander, flew to Baghdad last week to prepare his troops for the grim findings of the investigation. Many marines had witnessed the deaths of friends, he said. “The effects of these events can be numbing. There is the risk of becoming indifferent to the loss of a human life, as well as bringing dishonour upon ourselves.”
The conclusions are likely to provoke widespread revulsion.
President George W Bush said last week that the abuse at Abu Ghraib was one of his greatest regrets about the Iraq war. If the photographs from Haditha surface, they could provide a set of images that would be every bit as shocking.