Young Soldier Both Revered and Reviled

“All he said was, ‘I don’t know where these guys are getting this stuff,’ ” said Eric Thomas, a childhood friend here, shortly after speaking with Sergeant Gibbs by telephone one recent evening. “He said none of it actually happened. He said for some reason the other guys were scared. He doesn’t know where it comes from.”

“Calvin Gibbs is not a murderer,” Mr. Thomas said. “I don’t want people hearing about finger bones and thinking they know Calvin, because they don’t.”

Members of his unit in Afghanistan paint a devastating picture of Sergeant Gibbs, 26. He is one of five soldiers facing potential courts-martial on charges that they killed Afghan civilians for sport, planting weapons near them to fake combat situations, collecting their body parts and taking photographs posing with their corpses.

Documents in the case obtained by The New York Times, including statements by soldiers and investigators, portray Sergeant Gibbs as the ringleader in three separate incidents involving the murder of civilians near Kandahar, Afghanistan, this year, and as the force behind intimidating other soldiers in his unit to keep quiet. Soldiers said Sergeant Gibbs threatened at least one subordinate with death if he ever disclosed the killings. Other soldiers not accused in the deaths say he mocked them for not meeting his standard for men on patrol.

“He told me the type of soldier he was looking for was the type that could kill anybody without any kind of regret,” Pfc. Ashton Moore told an Army investigator in May.

When Private Moore, who faces other charges, told Sergeant Gibbs that he would not kill someone without cause, he said the sergeant responded: “And that’s why you’ll be stuck in the truck the whole time. The guy I’m looking for is the guy that would shoot the dude just because he could shoot the dude.”

The case has prompted the military to review all combat deaths with which Sergeant Gibbs has been involved, including those during deployments to Iraq as early as 2004.

Specialist Jeremy N. Morlock, also accused in the Afghanistan deaths, said Sergeant Gibbs had openly discussed how he might kill Specialist Adam C. Winfield, another one of the accused, who he worried would report the killings.

“There were two scenarios SSG Gibbs told me about taking his life,” Specialist Morlock told Army investigators as part of the investigation into the five soldiers. “The first scenario was going to take him to the gym and drop a weight on his neck. The second scenario was SSG Gibbs was going to take him to the motor pool and drop a tow bar on him.”

Geoffrey Nathan, a lawyer for Specialist Morlock, criticized the Army for allowing Sergeant Gibbs to lead troops in combat. He said his client “could serve the rest of his life in prison for being in the throes of Gibbs.”

Several soldiers recalled Sergeant Gibbs and Specialist Morlock tossing severed fingers in front of a soldier who had reported the widespread use of hashish within the unit. That soldier, Pfc. Justin A. Stoner, later told investigators that he feared being killed the same way Afghan civilians had been, as if his death had happened in combat.

“It wouldn’t be hard for them to take me out and do the same to me and blame it on the Taliban,” Private Stoner told investigators.

Here in Billings, Sergeant Gibbs’s friends say he was just performing his duty. “How could they put him in jail for doing his job over there?” Mr. Thomas asked. “I’m sure some people were shooting at him, so he shot back at them.”

Not long before he was deployed to war zones overseas, Sergeant Gibbs was a struggling teenager in Billings. “No ambition,” said a neighbor. His father worked in maintenance for the Mormon church and his family was active in the faith. He barely attended high school, earning just 1 of 20 credits necessary to graduate. In his high school yearbook during his sophomore year, he wore a T-shirt bearing the brand of a skateboarding company, “Independent.”