"That's probably why he got killed," his brother, Alex Hartley , said. "Being exposed like that, he probably took the brunt of the explosion."
Hartley 's nickname was "The Mighty Mosquito" because of his small size but fierce competitiveness in athletics.
"He was fearless in football and basketball," Hollifield said. "He would take anybody on; he swarmed them and that's how he got his nickname."
He joined the Army shortly after graduating from high school and deployed for a 13-month tour in Iraq.
"When he came back, he was going to get out of the military, but they told him they needed him," Alex Hartley said. "He said, 'No problem, I'll stay in as long as you need me."'
He returned for his second tour in March.
Hartley said his brother was committed to the military's mission in Iraq and pleased with the positive response he received from the Iraqi people.
"He said people he talked to were glad they were there," Alex Hartley said. "Protecting our country and helping people - he felt good about his mission."