Haditha is an agricultural community of about 90,000 people on the banks of the Euphrates north-west of Baghdad.
The dead in Haditha included members of whole families
It lies in the huge western province of Anbar, which became the heartland of the insurgency after US-led troops invaded Iraq in 2003.
It was 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 was then a regular occurrence - a roadside bomb targeting a US 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.
A simple US military statement hinted at the bloody chain of events that the attack started - though subsequent scrutiny showed it to be far from the truth.
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."
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, the following day a self-styled local journalist and human-rights activist, Taher Thabet al-Hadithi, got his video camera out and filmed scenes that - whatever they were - were not the aftermath of a roadside bombing.
The bodies of women and children, still in their nightclothes, apparently shot in their own homes; interior walls and ceilings peppered with bullet holes; bloodstains on the floor.
Haditha is considered hostile territory for US marines
A couple of months later, Mr Hadithi's tape was passed to the US newsmagazine Time, which published an account based on the footage.
The magazine also handed a copy of 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 bombing, the 15 civilians had been accidentally shot by marines during a gun fight with insurgents.
Nevertheless, on 9 March 2006 the top US commanders in Baghdad began a criminal investigation, led by the Naval Criminal Investigation Service (NCIS).
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 TJ Terrazas, far from coming under enemy fire, went on the rampage in Haditha after his death.
Twelve-year-old Safa Younis appears on video saying she was in one of three houses where troops came in and indiscriminately killed family members.
"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."
There were eight bodies in the house, including Safa's five siblings, aged between two and 14.
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.
In the street, US troops gunned down four students and a taxi driver they had stopped at a roadblock set up after the bombing.
According to a witness, they were shot by the side of the road, as they stood with their hands on their heads.
Trials and inquiries
Events in Haditha have been the subject of several official investigations as well as criminal charges against some members of Kilo Company, 3rd Battalion, 1st Marine Regiment alleged to have carried out the killings.
The alleged ringleader, Sgt Frank Wuterich, 28, was charged with voluntary manslaughter while L/Cpl Stephen Tatum was changed with involuntary manslaughter and aggravated assault.
Sgt Wuterich was the last man to have murder charges dropped
Murder charges were dismissed against all the marines from Kilo Company, including Sgt Sanick Dela Cruz, who was granted immunity in exchange for giving evidence to the military court.
The defendants have stuck to their initial account, that the dead were either assailants or civilians killed unwittingly in the crossfire.
Their supporters in the US have accused Mr Hadithi of being an insurgent himself, and distorting or actually fabricating the evidence.
Meanwhile, the US-backed Iraqi government launched its own inquiry, saying there was a limit to the "acceptable excuses" by the US military for causing civilian deaths, in this as well as a string of other high-profile cases in Iraq.
A report by the US military in Iraq found that senior marine commanders had been negligent in their failure to properly investigate the Haditha killings, and four officers were initially charged with dereliction and failing to report and investigate the killings.
Two had their charges dismissed by a military court in the US, but Lt Col Jeffrey Chessani became the most senior US serviceman since the Vietnam War to face a court martial for actions in combat.
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.