The U.S. government’s prosecution of four former Blackwater security guards is nearing an end this week, seven years after they were first accused of killing 14 people in Baghdad in one of the most controversial episodes of the Iraq war.

In closing arguments of the guards’ 10-week trial on homicide charges, U.S. prosecutors argued Wednesday that the guards fired recklessly and “out of control” at unarmed civilians in a botched security operation in Baghdad’s Nisour Square.

Assistant U.S. Attorney Anthony­ Asuncion described the proceedings in a federal court in Washington as a search for the truth about what happened on Sept. 16, 2007, and a declaration of “who should take responsibility” for the incident, which also left at least 17 others wounded.

“None of the victims stood a chance,” Asuncion said. “There were no insurgents out there that day.”

The guards’ attorneys have argued that their clients acted in self-defense. The men mistakenly believed that a white Kia sedan approaching their four-vehicle convoy was carrying a bomb, and responded to the sound of AK-47 gunshots, they said.

“Witness after witness testified that Raven 23 took incoming fire that day,” said attorney Brian Heberlig, referring to the name of the convoy. “This car was moving. This car was a threat.”

After another day of final arguments, jurors will get their chance to render a judgment on a dark and protracted chapter of the nation’s war in Iraq, one that has continued so long that its lessons have been overshadowed by fresh insurgent violence in the country.

Charges in the shooting were first brought against six Blackwater employees in 2008, one of whom, Jeremy Ridgeway, pleaded guilty to manslaughter and testified for the government in the current trial.

A federal judge threw out the other indictments in 2009, however, saying that prosecutors improperly relied on statements that the guards gave the State Department immediately after the shooting, believing that they would not be used in court.

A three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit reversed that ruling in 2011, saying U.S. District Judge Ricardo M. Urbina had misinterpreted the law, enabling prosecutors to obtain fresh grand jury indictments against the four current defendants.

The guards, all military veterans, are Paul A. Slough of Keller, Tex.; Nicholas A. Slatten of Sparta, Tenn.; Evan S. Liberty of Rochester, N.H.; and Dustin L. Heard of Knoxville, Tenn.

Each faces manslaughter charges except Slatten, a trained sniper who prosecutors said fired the first shots and who was charged with murder after prosecutors missed a deadline.

Overall, defendants are charged with the deaths of 14 Iraqis and the wounding of 17 others, and other gun charges.

The men were among 19 Blackwater Worldwide security guards providing security for State Department officials in Iraq. At the time of the incident, their convoy was clearing the way for another Blackwater team evacuating a U.S. official from a nearby car bombing.

But at the square near Baghdad’s Green Zone, guards opened fire with machine guns and grenades at the Kia sedan and then at other targets.

Before U.S. District Judge Royce C. Lamberth, the government presented wrenching testimony from what the Justice Department said was the largest number of foreign witnesses to testify in a criminal trial, as well as several other Blackwater guards, to make the case that the defendants led an “unprovoked and illegal attack” on civilians.

“People who could laugh, who could love, were turned into bloodied, bullet-riddled corpses,” Asuncion said. “How many of the bodies were shot in the back as they were seeking to escape from these men?”

Arguing that the only visible damage caused to the convoy’s command vehicle was caused by shrapnel from an American grenade, Asuncion said: “The ultimate irony of this case, ladies and gentlemen, is they did it to themselves. The damage was caused by them.”

The defendants’ attorneys called only four witnesses to dozens by the government. They presented Baghdad as a scene of “horrific threats” from car bombs, ambushes and follow-on attacks, sometimes aided by Iraqi security forces infiltrated by guerillas.

“Every civilian death in a war zone is a tragedy,” Heberlig said. “But not every death is a crime.” Heberlig blamed much of the violence on Ridgeway, whom he called a “complete fraud” and liar who implicated the others to avoid a 30-year mandatory minimum prison term.

Referring to his client, Slough, Heberlig said, “You can’t hold Paul responsible for Ridgeway’s shots.”

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