Cpl. Morlock describes how Sergeant Gibbs allegedly collected the fingers of some of his Afghan victims.
"It's his thing now," said Morlock. "I don't know, his crazy stuff. War trophies, whatever."
Morlock said Gibbs boasted of carrying out similar murders in Iraq but was never caught and threatened the men in his unit with harm if they refused to participate or revealed what was happening.
"If Gibbs knew that I was sitting in front of this camera right now, there's no doubt in my mind that he'd f---ing take me out if he had to," Morlock told the Army investigators.