Have any causes been found for the Connecticut shooting yet?

The guy was nuts. Does his motive really matter? What caused this was a maniac with access to powerful firearms.

The shooter definitely had some mental health issues, and the cause of these shootings can probably be found in the confused workings of his mind. It has been reported that he might have been autistic, or might have had asperger's syndrome. Another report said that he was thought to have a personality disorder of some kind. So take your pick. So far, these are the only possible explanations that have been suggested. I'm sure we'll hear much more about this as time goes by.

No, not yet. It was reported that the shooter had some kind of mental illness.