SAVANNAH, Ga. – Two years after Army Sgt. Deirdre Aguigui died suddenly in the middle of her pregnancy, military prosecutors in southeast Georgia plan to reveal at last why they believe she was killed by her husband, a young soldier accused by civilian authorities of using insurance money from her death to buy weapons for an anti-government militia group.

A military hearing for Pvt. Isaac Aguigui is scheduled to begin Monday at Fort Stewart, where he and his pregnant wife were stationed when she died in July 2011. The Army charged him in April with murder and with causing the death of his unborn child. A hearing officer will weigh evidence presented before advising commanders on whether to seek a court-martial for Aguigui, 21, of Cashmere, Wash.

“We still have never been told anything about how she died,” said Regina Ross-Schmid, an Army spouse who befriended Deirdre Aguigui at Fort Stewart. “People want to know what happened. Why did one of their fellow soldiers die with no explanation?”

The Article 32 hearing, similar to a civilian grand jury, is expected to uncover even more twists.

Aguigui and two fellow Fort Stewart soldiers already face the death penalty in the double-slaying of a former member of their infantry unit and his teenage girlfriend, who were shot in the woods outside the Army post just a few months after Aguigui’s wife died.

Civilian prosecutors say Aguigui recruited disgruntled soldiers to commit thefts, buy weapons and even kill for him as part of a militia group that talked of bombing a park fountain in nearby Savannah, poisoning apple crops in Washington state and even killing the U.S. president. Prosecutors said in court last year that Aguigui funded the group with $500,000 he received from his wife’s life insurance.

Exactly how Deirdre Aguigui died has never been disclosed publicly. Army investigators refused to say what caused it when they charged her husband with her murder months ago, and the military has denied requests for autopsy records and other documents by citing the ongoing criminal investigation. Ross-Schmid said soldiers in the woman’s unit were simply told she took a nap and never awoke.

She said Deirdre Aguigui was about midway through her pregnancy when she died. She had recently found out she was expecting a boy.

Isaac Aguigui met his wife, according to her obituary, at the U.S. Military Academy Prep School that prepares cadets for admission to West Point. But neither became an officer. By November 2010, both of them were stationed at Fort Stewart. Aguigui worked as an intelligence analyst in the Army’s 3rd Infantry Division, while his wife was an Army linguist. She became pregnant after returning from a deployment to Iraq.

Authorities jailed Isaac Aguigui nearly eight months later, but for a different crime. On Dec. 5, 2011, fishermen found the bodies of former Army Pvt. Michael Roark and his 17-year-old girlfriend, Tiffany York, in the woods of rural Long County near Fort Stewart.

Both had been shot in the head just two days after Roark was discharged from the Army. Investigators arrested Aguigui and three other soldiers and charged them with the deaths about a week later.