Killeen, Texas (CNN) – The gunman in Wednesday's shooting at Fort Hood, Spc. Ivan Lopez, had a history of instability.
"We have very strong evidence that he had a medical history that indicates an unstable psychiatric or psychological condition. (We're) going through all records to ensure that is, in fact, is correct. But we believe that to be the fundamental underlying causal factor," Lt. Gen. Mark Milley, the post's commanding general, told reporters Thursday.
