A white Kia was destroyed by members of a Blackwater convoy on Sept. 16, 2007, in Baghdad’s Nisour Squre that killed or wounded at least 31 unarmed Iraqi ciivilians. (Reuters)

A federal judge on Thursday sentenced a former Blackwater Worldwide security guard who helped secure long prison terms for four ex-colleagues to 12 months and a day in prison for his role in shootings that killed 14 unarmed Iraqis civilians in a Baghdad traffic circle in 2007.

U.S. District Judge Royce C. Lamberth of the District departed from sentencing guidelines for Jeremy P. Ridgeway, 44, who pleaded guilty to manslaughter in December 2008 and agreed to testify against the others.

Ridgeway, dressed in a dark suit, apologized to “all who grieved at my hands and those of Blackwater personnel,” to the Iraqi people and to the United States, “the land that I love.”

“I was charged with the protection of lives,” said Ridgeway, a U.S. Army and California Army National Guard veteran of the Iraq war. “I am sorry.”

Ridgeway, of Fallbrook, Calif., was supported by 88 members of his California community who wrote letters attesting to his charity work for veterans, and his Catholic parish and fraternal organization, 50 of whom traveled to be in court. His wife and two children, a 16-year-old daughter and 9-year old son, also joined him.

Ridgeway’s cooperation “significantly contributed to the achievement of justice,” federal prosecutors wrote in seeking leniency for the former guard, who faced a recommended term of 70 to 87 months.

Lamberth praised Ridgeway’s courage in delivering key testimony at trial, saying the jury believed him and not the lies of the convicted defendants.

“I can’t think of a case where I had a stronger feeling about your commitment to change your life, to do the right thing, to atone,” Lamberth said. “You did everything that you could” after the incident, he added. “I am proud of you.”

Lamberth in April sentenced Nicholas A. Slatten, of Sparta, Tenn., to life in prison on one count of murder. Three others, Paul A. Slough, of Keller, Tex.; Evan S. Liberty, of Rochester, N.H.; and Dustin L. Heard, of Maryville, Tenn., received terms of 30 years plus one day for multiple counts of manslaughter and attempted manslaughter.

A federal jury last year convicted the four men of recklessly firing machine guns and grenade launchers into a crowded traffic circle in Baghdad’s Nisour Square on Sept. 16, 2007, after one of them falsely claimed that their convoy was under threat. No evidence was found that they came under fire, nor were any insurgents among at least 31 Iraqi civilians who were killed or wounded.

The massacre marked a low point of the U.S. occupation and brought international criticism of the United States’ use of armed contractors. Blackwater’s founder, Erik Prince, eventually left the company, which was renamed Xe Services, then later sold and renamed Academi.

Ridgeway’s sentence, to be served in a minimum-security prison, could allow his release after about 10 months with credit for good behavior, and is to be followed by two years of supervised release. His attorneys asked for a sentence of five years of probation or a period of home detention.