Explaining To Do?
The FBI knew?

At least six months ago, Hasan came to the attention of law enforcement officials because of Internet postings about suicide bombings and other threats, including posts that equated suicide bombers to soldiers who throw themselves on a grenade to save the lives of their comrades.

They had not determined for certain whether Hasan is the author of the posting, and a formal investigation had not been opened before the shooting, said law enforcement officials who spoke on condition of anonymity because they are not authorized to discuss the case.

He was about to be deployed to Iraq. Didn't that make it a good time to find out for certain if it was him?