By CNN National Security Producer Jennifer Rizzo
When an insurgent rocket attack badly injured Cpl. Dustin Lee while he was on patrol in Iraq, his shrapnel-impaled partner, Lex, picked himself up to lie over Lee - an effort to protect him.
"He knew Dustin was injured," said Lee's mom, Rachel. Lex was his bomb-sniffing dog.
Lee didn't survive his injuries, but Lex did - and became a part of the Lee family when Rachel adopted him.
"When Dustin was killed, one of the first things I asked about was Lex, because of their camaraderie. They depended on each other"