A lot, both on and off camera. Our justice correspondent pamela brown is in fort hood. Pamela, what is the latest tonight on what youre hearing . Reporter well, a u. S. Military official with direct knowledge of the investigation telling our Barbara Starr that that traumatic brain injury that lopez had reported actually came from a reported fall during patrol, not from a traumatic event related to combat. And john, we learned from military officials today that there was an argument that escalated between lopez and another soldier in the moments right before this shooting. Officials believe that was the impetus. And according to a father of one of the victims, it all started over a leave request form. Cnn has learned in the weeks before his deadly rampage at fort hood, Army Specialist ivan lopez was creating a stockpile of ammunition. Sources say when lopez bought his. 45 caliber semiautomatic handgun at this store, guns galore in killeen, texas on march 1st, he also purchased what one