Thanks for those nidhogg, it definitely sheds more light on understanding his character, I feel he is still quite juvenile and possibily a loner who wants to feel part of something. I still think he is not guilty and his victims were white so I can't see any evidence this was racially motivated. The fact that the FBI could not find any links to any far-right or white supremacists groups, would lead me to believe he was a little coerced into making those gestures on that day. More images of him making the same gestures and hanging with the same people before and after this occurrence would sway me to believe otherwise.
As Sabang said, he is probably guilty of some low level law but not of murder. It is generally considered in most places in America, that if someone steps to you with the intent of doing you harm, you are well within your rights to shoot that man/ women cold dead.