Nov. 10, 2011  -- Staff Sgt. Calvin Gibbs was found guilty in a military court Thursday of being the leader of a U.S. Army thrill kill team that murdered three Afghan civilians for sport.

He was sentenced to life in prison, but will be eligible for parole in nine years. Gibbs was also found guilty of 12 related charges, including taking body parts as trophies from corpses.

Three soldiers who have already pled guilty in the case testified against Gibbs, who was accused of masterminding a scheme to kill unarmed civilians and then plant weapons to make the deaths appear justified.

"Sergeant Gibbs had a charisma, he had a 'follow me' personality," prosecutor Maj. Robert Stelle said in closing arguments Wednesday. "But it was all a bunch of crap. He had his own mission: murder and depravity."

Gibbs's defense attorney, Phillip Stackhouse, had argued that the other witnesses had framed Gibbs for the deaths, and that some admitted they had been under the influence of hashish while serving in Afghanistan.

Gibbs, who testified in his own defense, denied murdering civilians, but did admit to taking trophies from Afghans he said were killed legitimately. He compared cutting fingers from his human kills to "keeping antlers" from deer he'd shot.

The five-member jury at the Army's Joint Base Lewis-McChord south of Seattle deliberated for four hours before finding Gibbs guilty.

Twenty-six-year-old Gibbs, of Billings, Montana was among five soldiers from Lewis-McChord charged with taking part in the thrill kills in 2010 in a case that included allegations of widespread drug use, the collection of body parts and photos of the U.S. soldiers holding the Afghan bodies like hunter's trophies.

In a confession taped in May 2010 and obtained by ABC News, one of the soldiers admitted the team's role in the murders, but told Army investigators that Gibbs, his unit's "crazy" sergeant, had hatched the plan.

READ: Confession Video: U.S. Soldier Describes Thrill Kill of Innocent Afghans

"He just really doesn't have any problems with f---ing killing these people," Jeremy Morlock told military investigators during an interview videotaped at Kandahar Airfield, Afghanistan as he laid out the scenario he said the sergeant used to make it seem the civilians were killed in action.

"And so we identify a guy. Gibbs makes a comment, like, you know, you guys wanna wax this guy or what?" Morlock said." And you know, he set it up, like, he grabbed the dude."

Morlock said that killing people came "too easy" to Gibbs.

The corporal said Gibbs gave orders to open fire on the civilian at the same time Gibbs threw a hand grenade at the victim.

"He pulled out one of his grenades, an American grenade, you know, popped it, throws it, tells me where to go to whack this guy, kill this guy, kill this guy," Morlock told the investigators.

Morlock said Sergeant Gibbs carried a Russian grenade to throw next to the body of the dead Afghan, to make it seem he was about to attack the American soldiers.

The corporal said he opened fire as directed, fearful of not following Gibbs' orders.

"It's definitely not the right thing to do," Morlock told the investigators. "But I mean, when you got a squad leader bringing you into that, that type of real, that mindset, and he believes that you're on board with that, there's definitely no way you wanted him to think otherwise."

The investigator asked Morlock, "Because you felt maybe the next shot might be coming your way?"

"You never know. Exactly," answered Morlock. "I mean Gibbs talked about how easy it is, people disappear on the battlefield all the time."

A lawyer for Gibbs declined to comment. In March, Morlock pled to three counts of premeditated murder and was sentenced to 24 years in prison.

Holmes Kept Finger Bone from Victim

In September, Pfc. Andrew Holmes, of Boise, Idaho pled guilty to the unpremeditated murder of the first victim, as well as to drug use and to keeping a finger bone from the victim as a souvenir. Holmes had also posed for a photo, later leaked to the media, in which he held up the head of the dead victim.

Holmes, 21, admitted to the judge that he had fired his machine gun at the victim, that he knew the man was probably innocent , and that he believed he had caused the man's death.

Spc. Adam Winfield, who warned his parents that soldiers in his unit were executing innocent Afghan civilians, pled guilty in August to reduced charges and was sentenced to three years in prison for his role in the third killing, which took place in May 2010. He had been charged with premeditated murder, which carries a sentence of life in prison without parole.

Both Morlock and Winfield told Army investigators that Gibbs developed and rehearsed the murder of unarmed Afghans and later ordered his men to help him carry them out.

Spc. Michael S. Wagnon II, who is still awaiting trial, has pled not guilty. Wagnon is charged with participating in a cover-up of the second killing, which occurred in February 2010, as well as conspiracy and possessing a human skull fragment.

A lawyer for Wagnon has previously assailed Morlock's testimony, noting he requested investigative documents prior to testimony.

READ: 'Repugnant' Photos Emerge of U.S. Soldiers Accused of Sport Killings

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