Prosecutors accuse, clockwise from top right, Sgt. Anthony Peden, Pvt. Christopher Salmon and Pvt. Isaac Aguigui of murdering Michael Roark and Tiffany York. Pfc. Michael Burnett, top left, pleaded guilty to voluntary manslaughter and agreed to testify against the other defendants.

HINESVILLE, Ga. — Sgt. Deirdre Aguigui had been dead less than three months when a police officer alerted the Army and FBI: Her widower was stockpiling high-powered firearms.

The officer reported that Isaac Aguigui, a private on leave, bought 15 weapons at a store in East Wenatchee, Wash. His wife's battered body had been found in their home at Fort Stewart in Georgia, and the autopsy, noting the couple had "marital problems," said how she died was undetermined. He received $500,000 in life insurance benefits.

A relative alarmed by the purchases and unnerved by the unexplained death tipped off police, the officer, John Kruse, said. Still, Aguigui didn't break any laws in buying the guns, and was free to return to Georgia — where prosecutors say he amassed more firearms and committed murder.

The 21-year-old Aguigui and two other soldiers were charged Aug. 10 with killing two teenagers to conceal a plot to use $87,000 worth of munitions to blow up a fountain in Savannah, bomb a dam in Washington, overthrow the government and kill the president. Indictments four days ago widened the alleged conspiracy to a total of 10 people, eight of them current or former soldiers.

"The Army painted over something," said Brett Roark, whose son was one of the victims, shot in the head as he knelt in a south Georgia swamp. "If they knew, it's very wrong. If they didn't know, they're very stupid. Either way, a lot of people are dead and many lives are ruined."

Michael Roark, 19, and his 17-year-old girlfriend, Tiffany York, were killed Dec. 5 by four soldiers who were members of a band of would-be anarchists called FEAR, for Forever Enduring, Always Ready, according to the capital murder charges filed in rural Long County. The new indictments accuse a fifth soldier of tampering with evidence in the case and three former soldiers and a civilian of committing crimes to help finance FEAR.

The murder defendants had troubled histories that included petty crimes and violent threats documented in civilian court records, military files and a social-networking website. The Army took no action to discharge any of them before the murders.

That fit a pattern in which the military, desperate for manpower to fight prolonged conflicts in Afghanistan and Iraq, accepted more recruits with criminal records and discharged fewer who behaved badly while in uniform.

Normally, one felony or two serious misdemeanors bars a prospect from the Army. In 2006 alone, the Department of Defense issued 30,615 special dispensations that diluted that standard, more than double the total a decade earlier, amounting to 17 percent of all enlistees. That year, the military also reduced by 30 percent the number of troops discharged for misconduct and poor performance, according to data compiled by Bloomberg.

More sketchy recruits helped explain why violent crimes committed by active-duty soldiers at home and abroad rose 31 percent between 2006 and 2011 to 399 per 100,000 troops, according to an Army report issued in January. It found a crime is committed in the Army every six minutes, and a homicide every 63 hours, and cited growing "high-risk behavior with increasingly more severe outcomes."

"We saw this in Vietnam — you get these substandard troops and pretty soon you're screwed," said Barry McCaffrey, a retired four-star general who is a military consultant and analyst. "This put the military at risk."

Assistant District Attorney Isabel Pauley said Aguigui was FEAR's ringleader, an Army intelligence analyst who "actively recruited new members at Fort Stewart and targeted soldiers who were troubled or disillusioned."

One of his co-defendants in the murder case is Sgt. Anthony Peden, a 26-year-old veteran of three combat tours, two in Afghanistan. Peden was sent home from Iraq in August 2010 after threatening to shoot a fellow soldier, according to military records. Once back at Fort Stewart, he aimed a loaded rifle at his wife, she said in one of three complaints she filed with the police in Hinesville, Ga., before they divorced.

The third murder defendant is Pvt. Christopher Salmon, 25, who was demoted from specialist in August 2011 for reasons not made public. In the year before Salmon's 2006 enlistment, he was charged with 12 misdemeanors, including one for marijuana possession, police records show. That background would have disqualified him from service without one of the special exemptions, known as a moral conduct waiver.

The fourth soldier charged in the teenagers' deaths, Pfc. Michael Burnett, 26, pleaded guilty Aug. 27 to manslaughter and illegal gang activity. He said FEAR members saw themselves as revolutionaries who would "give the government back to the people."

The accused soldiers "are indicative of a military that has turned a blind eye to organized and violent groups within its ranks," said Matt Kennard, author of "Irregular Army: How the U.S. Military Recruited Neo-Nazis, Gang Members and Criminals to Fight the War on Terror."

With the exception of Burnett, the defendants haven't entered pleas. Their lawyers either declined to comment or didn't respond to telephone calls.

Army and FBI officials declined to comment on the tip from the police officer in East Wenatchee.

"We do everything we can with local, state and federal law enforcement to prevent crime," said George Wright, a spokesman at the Pentagon. "We take some very aggressive measures. There are times criminals outwit law enforcement."

The Army Criminal Investigation Command had been familiar with Aguigui since he reported finding his wife's body on July 17, 2011, one or two hours after the couple had sex, he told authorities. A linguist who spoke Arabic and had served in Iraq, she was 24 and five months pregnant. The autopsy inventoried "blunt force injuries" to her head, arms and back. The postmortem "did not detect an anatomic cause of death."

Her death is under investigation, said Chris Grey, a spokesman for the command in Quantico, Va.

Aguigui, the son of a career soldier who moved frequently, had been going on anti-government tirades for years, according to a childhood friend, Phylicia Hanson.

"He was paranoid that they were corrupting us and taking over the world," Hanson said. Aguigui had wanted to be the center of attention since they were kids, she said, talking about how important it was to "do something big."

In March 2009, he posted on his MySpace page a threat to an unnamed person, writing that "nothing would please me more than to personally finish you off" and that "prison sounds lovely to me." Pauley, the assistant district attorney, said he described himself on a recording discovered after his arrest as "the nicest cold-blooded murderer you will ever meet."

In July 2009, Aguigui was accepted into the U.S. Military Academy Preparatory School, a program that put him on a track for officer training at West Point in New York.

He was kicked out in November for breaking the rules by dating his future wife, a fellow cadet who also had to leave, according to her father, Alma Wetzker. They married in December.

At Fort Stewart, Aguigui assessed whether soldiers were fit to join FEAR by watching their reactions to a trailer for a video game in which a vigilante group acts as judge, jury and executioner on behalf of victims of economic inequality, Pauley said. She said he called this test "the awakening."

The Saturday before the murders, Anthony Peden showed up at a bar in Savannah where his ex-wife worked. "We're involved in some really bad stuff," Landri Peden said her former husband told her. "I could tell he was scared. He was acting crazy."

She said she and two friends drove him back to the base, about an hour away. He was ranting, she said, saying, "If you find out anything that's going on, they'll kill you."

That Monday night, the four FEAR members rolled into an alligator-infested swamp of cypress and oak trees known as Morgan Lake, in a tan Jeep Cherokee loaded with handguns and several boxes of ammunition, according to state investigative records. Roark and York followed in a black Nissan Altima.

Roark had received a less-than-honorable discharge from the Army four days earlier for drinking and disciplinary issues, according to his father. York, a high school junior, had been dating him for a few months, her mother said.

The occupants of the two vehicles communicated with walkie- talkies, navigating inlets filled with water moccasins and rattlesnakes where they often went to practice target-shooting, according to the records and interviews.

The teenagers had $500, money they planned to use for a West Coast trip, Roark's father said. He said his son had agreed to help Aguigui set up a private security company in Washington but was having second thoughts. The company was to have been a front for FEAR's criminal activities, according to prosecutors.

At an isolated turnout, Aguigui allegedly directed the vehicles to stop and pressed the soldiers into action.

Peden shot York in the face as she sat in the Nissan, took her pulse, and then shot her again, according to Burnett's testimony in court. Peden then handed the Taurus Judge .410 caliber handgun to Salmon, who shot Roark, Burnett said.

The four soldiers stripped off clothes splattered with blood and brain matter and burned them in Peden's backyard, according to a Georgia Bureau of Investigation search warrant.

That Saturday, they were called to an unscheduled formation at 6 a.m. and arrested by military police in battle gear, said Long County Sheriff's Lieutenant Thomas Sollosi. "It's the most sinister case I've ever been involved with," Sollosi said. "It shocks the conscience of anyone with morality."

Later that day, Landri Peden said a social worker called her to pick up her 3-year-old son, who was visiting her ex- husband. When she went to collect his clothes, she said, she saw loaded firearms, boxes of ammunition and gun racks throughout the house near the base, including in her son's bedroom.