A former security contractor for Blackwater USA will not be indicted in the killing of an Iraqi guard in 2006, federal prosecutors said Monday.

According to a congressional report, Seattle resident Andrew Moonen was wandering drunk around Baghdad's Green Zone after a Christmas Eve party in 2006 when he encountered and fatally shot Raheem Saadoun, a 32-year-old guard for Iraqi Vice President Adil Abd-al-Mahdi.

But U.S. Attorney Jenny Durkan said Monday that prosecutors decided there wasn't enough evidence to sustain a criminal conviction for the killing.

"We do not do this lightly," Durkan wrote in a letter to Moonen's attorney, Stewart Riley. "There is no question that the shooting death of Mr. Saadoun by your client was a tragic event."

Riley said he was elated for his client.

"He acted in self-defense," Riley said. "He returned fire, ran for his life to a nearby checkpoint and reported the incident immediately."

U.S. ambassador to Iraq James Jeffrey has informed Iraqi government officials of Durkan's decision, and provided a letter to be delivered to Saadoun's family, the federal prosecutor's office in Seattle said.

Durkan said Moonen admitted he shot Saadoun the day after the slaying, claiming self-defense.

Riley said the past four years have been stressful for Moonen, adding the Army veteran has lost out on job opportunities and has not been able to serve in Iraq or Afghanistan as an Army reservist. Riley said Moonen served a seven-month tour in Iraq before working for Blackwater.

"He will now attempt to put this very difficult time in his life behind him and hopefully move on," Riley said in a statement. "Unlike some in Congress and some in the news media, the United States Attorney's Office did not rush to judgment and appears to have been decidedly immune from outside pressure."

In 2008, federal prosecutors, FBI agents and other officials traveled to Iraq to investigate whether they could charge Moonen, interviewing witnesses and reviewing available records.

"After a thorough review of the above-described materials, and an analysis of the facts of this case and the applicable law, we have decided to close the investigation of Mr. Moonen without asking a grand jury to return an indictment against him," Durkan wrote.

Riley declined to say where Moonen lives or currently works.

After the shooting, Blackwater arranged to have the State Department fly Moonen, a former Army Ranger, back to the United States. The company then fired him and fined him. Blackwater paid Saadoun's family $15,000.

A federal lawsuit filed by Saadoun's widow in 2009 against Moonen was dismissed, Riley said.


Associated Press Writer Gene Johnson contributed to this report.