His fiancee Abby Malone said the couple was planning to marry in May, according to affiliate WOOD-TV. Malone told the station she is "more proud (of Taylor) than I can say."

Lance Cpl. Mason J. Vanderwork: Another mortarman with a host of medals to his name, the 21-year-old was from Hickory, N.C. He, too, served in Afghanistan and accumulated a number of medals along the way.

At St. Stephens High School where he graduated in 2010, his former football coach Chip Watts said he was like a son to him and a tough team player.

"Pure tenacity. Work ethic. Desire," Watts told affiliate WSOC. "Whatever the kid did, he did it 100 miles per hour."

Wanderwork leaves behind a wife.

Lance Cpl. William T. Wild IV: In October 2010, the Anne Arundel, Md., resident joined the Marines. By December 2011, the mortarman had earned his new rank, and he also earned a number of recognitions, such as the Combat Action Ribbon and Global War on Terrorism Expeditionary Medal. He was 21.

Authorities still don't know how the men died. McNulty said Wednesday they know only that the "60 mm mortar system failed to function as designed," and are trying to find out why.

Hawthorne Army Depot, about 140 miles southeast of Reno, is used for storing ammunition and weapon stocks awaiting demilitarization. The facility also provides high-desert training facilities for military units.

The night after the incident, the Marines issued a statement saying that 60 mm mortar rounds and tubes used to fire them are being pulled pending the investigation.

In addition to the dead, eight service members were injured in the explosion. The Wednesday night update from the Marines indicates that a Navy Corpsman remains "very seriously injured," while five others are "seriously injured." Two Marines have been treated for minor injuries and released.