Nicholas Slatten, pictured in June, was found guilty of murder on Wednesday. (Cliff Owen/AP)

A federal jury has found four former Blackwater security guards guilty in the killing of 14 Iraqis in 2007, an episode that destroyed the reputation of the military contractor and damaged relations between the U.S. and the Iraqi government.

After an 11-week trial, Nicholas Slatten was convicted of first-degree murder, and three other guards–Dustin Heard, Evan Liberty, and Paul Slough–were found guilty of manslaughter and other charges. The jury presented those initial verdicts and is still deliberating on other charges in the 33-count indictment.

The case stems from the Sept. 16, 2007, killings that caused an international uproar over the government's use of private contractors to protect American diplomats during the nearly decade-long Iraq War. Attorneys for the defendants argued they were ambushed in Nisour Square, but prosecutors argued the killings were unprovoked. Reviews by the FBI and the military found that the deaths were unjustified. Former Blackwater guards had testified that the company's employees were "generally distrustful" of Iraqis, according to the Associated Press.

Heard's attorney, David Schertler, vowed to appeal, the Wall Street Journal reported.

“The verdict is wrong. It’s incomprehensible. We’re devastated,” Schertler said. “We’re going to fight it every step of the way. We still think we’re going to win.”

Liberty's lawyer also said his client would appeal, while the attorneys for the other defendants declined to comment after the verdict, the paper reported.

The incident outraged the Iraqi government, which demanded that the U.S. end its contract with Blackwater. The U.S. finally did so in January 2009, shortly after Barack Obama became president. The company changed its name to Xe shortly thereafter, and later changed it again to Academi LLC.

The charges came down in 2008, and the case has been mired in legal battles that delayed the trial for years, the AP noted.