WASHINGTON (AP) — President Donald Trump on Tuesday pardoned four former government contractors convicted in a 2007 massacre in Baghdad that left more than a dozen Iraqi civilians dead and caused an international controversy over the use of private security guards in a war zone.

Supporters of the former contractors at Blackwater Worldwide had lobbied for the pardons, arguing that the men had been excessively punished in an investigation and prosecution they said was tainted. All four were serving lengthy prison sentences.

“Paul Slough and his colleagues didn’t deserve to spend one minute in prison,” said Brian Heberlig, a lawyer for one of the four pardoned defendants. “I am overwhelmed with emotion at this fantastic news.”

The pardons were issued in the final days of Trump’s single term. Last November, he pardoned a former U.S. Army commando who was set to stand trial next year in the killing of a suspected Afghan bombmaker and a former Army lieutenant convicted of murder for ordering his men to fire upon three Afghans.

The Blackwater case has taken a complicated path since the killings at Baghdad’s Nisoor Square in September 2007, when the men, former veterans working as contractors for the State Department, opened fire at the crowded traffic circle.

Prosecutors asserted the heavily armed Blackwater convoy launched an unprovoked attack using sniper fire, machine guns and grenade launchers. Defense lawyers argued their clients returned fire after being ambushed by Iraqi insurgents.

They were convicted in 2014 after a months-long trial in Washington’s federal court, and each man defiantly asserted his innocence at a sentencing hearing the following year.

“I feel utterly betrayed by the same government I served honorably,” Slough told the court in a hearing packed by nearly 100 friends and relatives of the guards.

Slough and two others, Evan Liberty and Dustin Heard, were sentenced to 30 years in prison, though after a federal appeals court ordered them to be re-sentenced, they were each given substantially shorter punishments. A fourth, Nicholas Slatten, whom prosecutors blamed for igniting the firefight, was sentenced to life in prison.

A federal appeals court later overturned Slatten’s first-degree murder conviction, but the Justice Department tried him again and secured another life sentence last year.

Heard’s lawyer, David Schertler, said they were “thrilled and grateful” for the pardon. “We have always believed in Dustin’s innocence and have never given up the fight to vindicate him. He served his country honorably and, finally today, he has his well-deserved freedom.”

A lawyer for Liberty, Bill Coffield, said, “These are four innocent guys and it is completely justified.”

The American Civil Liberties Union decried the pardons. Hina Shamsi, the director of the organization’s national security project, said in a statement that the shootings caused “devastation in Iraq, shame and horror in the United States, and a worldwide scandal. President Trump insults the memory of the Iraqi victims and further degrades his office with this action.”

The trial was held years after a first indictment against the men was dismissed when a judge ruled that the Justice Department had withheld evidence from a grand jury and violated the guards’ constitutional rights. The dismissal outraged many Iraqis, who said it showed Americans considered themselves above the law.

Joe Biden, speaking in Baghdad in 2010 as the vice president, expressed his “personal regret” for the shootings in declaring that the U.S. would appeal the court decision. The Justice Department later revived the case.

Blackwater contractors in Baghdad were frequently accused of firing shots without provocation.

However, armed militants opposed to the U.S. presence in Iraq frequently deployed vehicle bombs next to Western and Iraqi motorcades in traffic, making the ubiquitous armed guards accompanying most dignitaries extra cautious — and in Blackwater’s case, insistent about not allowing other vehicles near them.

The Blackwater firm was founded by Erik Prince, the brother of Education Secretary Betsy DeVos. It has since been renamed.

Associated Press writer Ellen Knickmeyer in Oklahoma City contributed to this report. Trademark and Copyright 2020 The Associated Press. All rights reserved.