After years of delays, four former guards from the security firm Blackwater Worldwide are facing trial in the killings of 14 Iraqi civilians and the wounding of 18 others in bloodshed that inflamed anti-American sentiment around the globe.
A trial in the nearly seven-year-old case is scheduled to begin with jury selection today, barring last-minute legal developments. Prosecutors plan to call dozens of Iraqis to testify in what the Justice Department says is likely to be the largest group of foreign witnesses ever to travel to the US for a criminal trial.
The violence at the Nisoor Square traffic circle in Baghdad on September 16, 2007 was the darkest episode of contractor violence during the war in Iraq, and one more diplomatic disaster in a war that had many.
Iraqi officials, who wanted the guards tried in a local court, were outraged.
"The core disputed issue in this prosecution is self-defence - whether the defendants believed that deadly force was necessary to defend themselves and their teammates from an insurgent attack, and whether that belief was objectively reasonable," lawyers for the guards said in court filings.
The Nisoor Square shootings spelled the death knell for the company formerly known as Blackwater Worldwide. It was sold to a group of investors who changed the name to Academi.
In 2009, US District Judge Ricardo Urbina dismissed the case against the Blackwater guards.
But two years later, a panel of the US Court of Appeals for the District of Columbia revived the prosecution, ruling that Urbina had wrongly interpreted the law. The decision gave the Justice Department another chance.
In the upcoming trial, one of the guards, Nicholas Slatten, is charged with first-degree murder. The other three guards - Paul Slough, Evan Liberty and Dustin Heard - are charged with voluntary manslaughter, attempted manslaughter and gun charges.