It appears Major Malik Nadal Hasan was a psychiatrist who used to work at Walter Reed Hospital and was transferred to Fort Hood this past summer.
Some other tidbits......
He was always a Muslim of Middle Eastern ethnicity and not a convert.
He got a "poor" performance rating in his job at Walter Reed. He was known to be against the operations in Iraq and Afghanistan and felt that Muslims there had a right to fight back against the Americans.
Yet, despite these controversial views in an American military officer he was still promoted to the rank of Major last Spring. That must be the "diversity embracing" government policies at work for you.
The media is claiming he was upset about being deployed to a forward position in either Iraq or Afghanistan.
Almost no one wants to go to Iraq or Afghanistan, but they don't plan out and execute a mass murder terrorist attack on their colleagues.
It's beginning to look more like he didn't want to be in an adversarial position to his Islamic brothers fighting for Jihad.
Move on... nothing to see here.