Yeah he knows, but Corsi gave his word to keep his mouth shut until the Posse releases the evidence.
He was absolutely giddy in an interview last month about what Arpaio's Posse has found in Hawaii about Obama.
How would he react if his family is credibly threatened? Any threat to his family from a Democrat President's agents would be necessarily credible. Think about Clinton's string of interesting deaths and the homosexual choir members who were murdered in Chicago at the time when one of them threatened to be a problem for the kenyan.