A former Blackwater security guard was convicted of first-degree murder Wednesday for killing the first of 14 unarmed civilians in a barrage of gunfire in a crowded Baghdad traffic circle in 2007, an episode that drew international condemnation during the Iraq War.

It was the second time a federal jury in Washington convicted Nicholas A. Slatten, 35, of murder in the death of 19-year-old Ahmed Haithem Ahmed Al Rubia’y. His 2014 conviction was overturned on appeal, and a second trial last summer ended in a hung jury. Slatten now faces a mandatory life sentence without parole.

The jury foreperson told The Washington Post that jurors rejected Slatten’s claim that his convoy of guards fired on Al Rubia’y in self-defense. “In our determination, there were no justifiable deaths,” the foreperson said. “No justifiable shooting.”

The outcome brings a muted end to an incident that triggered diplomatic and humanitarian protests over the U.S. government’s use of private military forces and marked one of the lowest points of the Iraq War.

Three other Blackwater guards who were part of Slatten’s convoy also were convicted in 2014, of manslaughter and other charges. The verdicts for Paul A. Slough, Evan S. Liberty and Dustin L. Heard were not reversed, but the 30-year sentences they received were vacated on appeal. No sentencing date has been set for any of the four defendants, all of whom are in custody.

In Nisour Square, on Sept. 16, 2007, Slatten was one of 19 Blackwater security contractors in a convoy of four heavily armed trucks using the call sign Raven 23. But after a car bombing earlier in the day, the team disregarded an order to stay in the Green Zone and set up a blockade in the square, prosecutors said.

A white Kia, driven by Al Rubia’y with his mother in the passenger seat, headed toward the blockade. Prosecutors alleged Slatten, of Sparta, Tenn., fired the first shots into the Kia and intentionally set off a rampage in which more than 30 people were shot, 14 fatally.

The Blackwater guards claimed that they feared the Kia might be used as a car bomb and that after they began firing on the Kia, the guards took small-arms fire from other sources which disabled one of the Blackwater trucks. The guards then fired into a bus and other vehicles, compounding the carnage.

“There had been a lookout for a white Kia,” the jury foreperson told The Post. “But there’s a million Kias in Iraq, you don’t just shoot every white Kia.”

The foreperson said the jury “didn’t believe the white Kia presented or could be perceived as a threat. And we didn’t perceive that the convoy was taking small-arms fire.” The foreperson said the jury believed shrapnel from grenades launched by the Blackwater guards damaged their own vehicle.

The foreperson spoke on the condition of anonymity due to concern about possible retribution from supporters of the Blackwater guards.

In 2014, a jury in Washington convicted Slatten of murder and Slough, Liberty and Heard of manslaughter and attempted manslaughter. One other guard reached a plea deal for reduced sentences.

In August 2017, a federal appeals court tossed Slatten’s life sentence and ordered a new trial, saying he should have been tried separately from Slough, 39. Slough had told investigators days after the shootings that he, not Slatten, fired the first rounds.

Slatten then received a retrial that ended in a hung jury in September, with the defense saying the convoy members had been acting in self-defense.

The third trial started Nov. 5.

Slatten’s defense team declined to comment after the verdict.

At trial, Slatten’s defense seized on shifting statements by Blackwater convoy members who had testified against Slatten in his earlier trials.

They included Jimmy Watson, the leader of the four-vehicle convoy and Slatten’s vehicle mate, who retreated from earlier testimony to a grand jury that he had heard Slatten fire first, and Jeremy Ridgeway, who pleaded guilty to manslaughter and testified for prosecutors in a plea deal.

Slatten lead defense lawyer Dane Butswinkas said to jurors in his closing argument, “Mr. Al Rubia’y’s death is a tragedy. There’s no doubt about that. But this is not a reason to compound the tragedy, by sending an innocent person to prison for as long as Mr. Ridgeway would have gone had he not cooperated.”

Prosecutors argued Slatten acted out of general hatred for Iraqis and a misguided desire for revenge for the 2001 terrorist attacks on New York City and Washington.

They said Ridgeway’s shifting memory was mistaken and that Watson’s actions were an ongoing attempt to coverup responsibility for the attacks.

Referring to Slatten, prosecutor Fernando Campoamor-Sanchez told jurors, “You know that this man took this sniper rifle, and through this scope he took aim at Ahmed’s head, and he fired. Boom. And he fired again. Boom. And why?” Campoamor-Sanchez said in his closing argument. “Because, ladies and gentlemen, he thought he could get away with it. Nobody would know. He would never have to answer to people like you sitting in this jury room today.”

The foreperson said, “We quickly got rid of self-defense” as a cause for the killings. The jury was aware that Slough had been convicted, that Ridgeway had pleaded guilty and Watson had been granted immunity. They did not know that Liberty and Heard had also been convicted, the foreperson said.

The jury deliberated for five days after a five-week trial.

Slough, Liberty and Heard received 30 years — twice the maximum punishment for manslaughter alone — after being convicted of using military firearms while committing a felony, an enhanced penalty that was primarily aimed at gang members and had never been used against security contractors given military weapons by the U.S. government.

The appeals court ruled the punishment meted out to the three guards violated a constitutional prohibition against “cruel and unusual punishment.”

Charges were first brought against six Blackwater employees in 2008, but the extraordinary prosecution suffered numerous turns and setbacks.

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

An appeals panel reversed that ruling in 2011, clearing the way for prosecutors to obtain fresh indictments against Slatten and the three others.

However, prosecutors took so long to charge Slatten that the statutory time limit for bringing a manslaughter charge had expired, an error the appeals panel said also stemmed from an errant court ruling, a court found.

The Justice Department responded by charging Slatten, a former Army sniper, with first-degree murder, which has no statute of limitations.

The foreperson was troubled that Slatten faced only one charge and no lesser alternatives, particularly since the only sentence would be a mandatory life term. The foreperson was unsure whether Slatten truly premeditated the shooting, other than the moments staring down the scope as the white Kia sat in the traffic near the convoy.

“I think the murder one,” the foreperson said, “I understand it, but there’s a bit of unjustness to it.”

Thirty Iraqi shooting survivors and relatives of victims testified in person in a 2014 trial, marking the largest number of foreign witnesses to travel to the United States for a criminal trial, prosecutors said at the time.