The six month window hiatus in the middle of training for treatment of depression offers a few possibilities for subtle conditioning. Depends on who was giving him treatment. Still a lot of ex-stasi in the tall grass over there. Some with long standing ties to arab terrs.
Aha, a possible Professor Raoul X.
http://westernrifleshooters.wordpress.com/2011/01/14/bracken-professor-raoul-x/
He also is said to have attended a flying school in Arizona at some point.. wonder if it is the same one that some of the 9/11 murderers attended.. I think they were in Florida too.