"Here was a man you could trust not just with your own life, but with the lives of all your men," says a Special Operations operative who served in combat with Wheeler of Army Master Sgt. Joshua Wheeler, 39, who died in Iraq Thursday

By Susan Keating
Updated October 23, 2015 05:00 PM
Credit: U.S. Army

Army Master Sgt. Joshua Wheeler, who was the first American service member to be killed in action while fighting ISIS, was a peaceful, gentle man who was devoted to his family and proud to be in uniform, a relative tells PEOPLE

“I want the world to know what a good person he was,” says his aunt, Elizabeth Brown, 45, of Jones, Oklahoma, “and how much he loved his family and his country.”

Wheeler, 39, who was a member of Delta Force – one of the military’s most elite and secretive commando units – died from wounds received Thursday in the course of a hostage rescue operation in Kirkuk Province, Iraq, the Army confirms. The mission happened after freshly dug mass graves were spotted inside the compound, a military source with knowledge of events tells PEOPLE.

He was stationed at Fort Bragg, North Carolina, served in Special Operations Command, and deployed 11 times to Iraq and Afghanistan. In addition to other assignments, the Army says, Wheeler also served with the Army’s storied 75th Ranger Regiment.

“Here was a man you could trust not just with your own life, but with the lives of all your men,” says a Special Operations operative who served in combat with Wheeler, and who cannot speak for attribution because he is on active duty. “He was honorable. He was made of loyal.

“He was built of courage,” the operative said. “His loss is more than a hole. It’s a gaping wound within the brotherhood.”

Wheeler was particularly proud of being a Ranger, says his aunt.

“He was so excited,” Brown says through tears. “It was such an accomplishment, and he was so proud.”

Wheeler was in his 20s and met up with Brown at a family reunion in Wyoming shortly after his graduation, she says.

While there, Brown and Wheeler – at eight years his aunt’s junior, more like a brother – went alone on a hike.

They sat down to enjoy a picnic lunch.

“He fed his lunch to the chipmunks,” Brown says. “They came right up to him and ate right out of his hand.

“It was so nice to see him so relaxed and happy,” Brown says. “He had such a peaceful, gentle side.”

The extended Wheeler clan, along with friends and colleagues, are devastated at Wheeler’s loss, contacts say.

“This is a great, great loss to his family, the Army, and country,” says an active duty soldier who cannot be named because he currently serves within Special Operations Command.

Wheeler was a highly decorated war hero, the Army affirms. His numerous awards and decorations include four Bronze Stars for valor, and additional seven Bronze Stars, and additional valor awards.

Wheeler’s most recent medal is the Purple Heart, awarded posthumously from the action that killed him, an Army spokesman tells PEOPLE.