That's not their stance at this point, though. They claim to have dropped the inquiry because he didn't pose a threat.
I wouldn't trust anything the Pentagon/FBI is saying. That's just me, but maybe some people do believe everything they hear.
Given what's available at this point, I can understand the sentiment. They're not saying they may have known about him. They are saying they did and dropped it.
Mike
You can't "know" what someone is going to do.. I can tell you that if this guy went around saying "I'm going to kill a bunch of people at Fort Hood" he would have been busted, but (unless I missed something new) he did not go around saying that.
There are many documented cases where a person of suspicion is being monitored and they do something unexpected, granted it looks bad on the hands of the Pentagon and the overall Government, there is still a (IMHO) big possibility that the Government was watching this guy in hopes to catch/uncover others. This is the information age, you don't send Emails to known accomplices of the 9/11 hijackers and just go unnoticed/cast to the side by the Gov'mnt.

