[Governor Dinwiddie]

The best explanation of this massacre which I've heard is that it was an entrapment sting operation run by the FBI that went wrong. The shooter found out he was busted and went down in a blaze of gunfire.

This would explain why we know NOTHING after all these months. Chalk this one up as another in the vein of TWA Flight 800.
 

[AppyPappy]

A better explanation is terrorism. He was funded by terrorists and they gave him two options: Being tortured to death or do their bidding.