If you are asking this question, you are a very unintelligent individual. What on Earth does it possibly matter? It's as relevant to the shooting as whether he had blue or brown eyes. I've received five e-mails already with people bugging me about this. Apparently, there is some Mommy of an autistic who is desperate for attention and who is screeching "Asperger's caused it" on several websites. See an example here.
It is true that people with Asperger's can become violent. It is also true that people who don't have Asperger's can become violent. I know that we are in the midst of "let's-blame-autism-on-everything-that-is-wring-with-the-world" wave, but there should be a limit. Asperger's doesn't cause people to shoot into crowds. Contrary to what you have heard, it isn't a disease, an epidmic, or the end of the world. It's a way of being that does not cause unrelieved misery for those who live it. And, once again, it doesn't make people shoot into crowds. I've lived with Asperger's for 34 years and am still to commit a violent act against anything other than the copy machine. Trying to "predict" that one will become a mass murderer on the basis of Asperger's makes about as much sense as basing your prediction on a person's height, weight, or hair color.
I understand that thinking is a difficult chore for many people and nobody wants to make the effort. But dismissing the shooting by attaching to it a label of "Asperger's", "learning disorder," "schizophrenia," or "Mommy issues" is a very stupid thing to do.