By Martin Asser BBC News

Young and old victims were filmed, many in nightclothes

It lies in the huge western province of Anbar, which has been the heartland of the insurgency since US troops led the invasion of Iraq to overthrow Saddam Hussein in 2003.

It is a dangerous place for the US marines who control this part of Iraq and for the inhabitants, caught between insurgents and American troops.

On the morning of 19 November 2005, the Subhani neighbourhood was the scene of an event that has become like the pulse of the insurgency - a roadside bomb targeting a US military patrol.

It killed 20-year-old Lance Corp Miguel (TJ) Terrazas, driving one of four humvee vehicles in the patrol, and injured two other marines.

It said: "A US marine and 15 civilians were killed yesterday from the blast of a roadside bomb in Haditha.

"Immediately following the bombing, gunmen attacked the convoy with small arms fire. Iraqi army soldiers and marines returned fire, killing eight insurgents and wounding another."

Video footage

The tragedy of Haditha may have been left at that - just another statistic of "war-torn" Iraq, a place too dangerous to be reported properly by journalists, where openness is not in the interests of political and military circles, and the sheer scale of death numbs the senses.

However, a day after the incident, local journalist Taher Thabet got his video camera out and filmed scenes that - whatever they were - were not the aftermath of a roadside bomb.

Haditha is considered hostile territory for US marines

Mr Thabet's tape prompted an investigation by the Iraqi human rights group Hammurabi, which passed details onto the US weekly magazine Time in January.

Before publishing its account on 19 March, the magazine passed the tape to US military commanders in Baghdad, who initiated a preliminary investigation.

Following their findings, the official version was changed to say that, after the roadside bomb, the 15 civilians had been accidentally shot by marines during a firefight with insurgents.

Nevertheless, on 9 March the top commanders in Baghdad began a criminal investigation, led by the Naval Criminal Investigation Service (NCIS). Its report is expected within days.

On 7 April three officers in charge of troops in Haditha were also stripped of their command and reassigned.

Pretended to die

Eyewitness accounts suggest that comrades of Lance Corp Terrazas, far from coming under enemy fire, went on the rampage in Haditha after his death.

A US soldier came in and shot at us, I pretended to be dead and he didn't notice me Safa Younis

"They knocked at our front door and my father went to open it. They shot him dead from behind the door and then they shot him again," she says in the video.

"Then one American soldier came in and shot at us all. I pretended to be dead and he didn't notice me."

Hammurabi says eight people died in the house, including Safa's five siblings, aged between 14 and two.

In another house seven people including a child and his 70-year-old grandfather were killed. Four brothers aged 41 to 24 died in a third house. Eyewitnesses said they were forced into a wardrobe and shot.

Outside in the street, US troops are said to have gunned down four students and a taxi driver they had stopped at a roadblock set up after the bombing.

Damage

The Pentagon has said little about the Haditha deaths publicly, and in Iraq the incident has caused little controversy - US troops there are already routinely viewed as trigger happy and indifferent to Iraqi casualties.

But politicians in Washington who have been briefed on the military investigation say it backs the story that marines killed civilians in cold blood.

The chairman of the Senate armed services committee, John Warner, says it will hold hearings into the incident and how it was handled.

Media commentators have spoken of it as "Iraq's My Lai" - a reference to the 1968 massacre of 500 villagers in Vietnam.

Democrat congressman John Murtha, a former marine and war veteran, has said the Haditha incident could turn out to be an even bigger scandal than the Abu Ghraib prison abuse scandal.

The Marine Corps has responded to Mr Murtha by saying it would be inappropriate to comment on an ongoing investigation, but would do so "as soon as the facts are known and decisions on future actions are made".

1) Marine Lance Corp Miguel Terrazas dies in attack on US convoy. 2) US military initially says bomb also killed 15 Iraqi civilians. 3) Eight insurgents killed after attacking convoy. US later says the 15 civilians were not killed by bomb, but shot accidentally in battle.

1) Marine Lance Corp Miguel Terrazas dies in bomb attack on convoy of four Humvees. Troops then "go on rampage". 2) At roadblock, four students and taxi driver killed. 3) Eight people killed in one of three houses. 4) Seven killed in a second house. 5) Four brothers put in wardrobe and shot dead in a third house.