Operation "Able Danger"

I've just read the disturbing news that a Pentagon employee is claiming to have destroyed key documents pertaining to the identification of Mohammed Atta as a terrorist back in 1999 at the orders of his supervisor. Apparently the documents were the result of a secret Clinton-era intelligence operation known as "Able Danger" - whose existence was so secret that 9/11 Commissioner Slade Gordon has stated "It just didn't happen." Does anyone know anything more about this operation or the circumstances under which the employee was ordered to destroy the documents? I won't prejudge the facts, but on the surface this seems like fuel for the fire for those who have claimed that the federal government had detailed knowledge of the movements of the hijackers. Recall, for instance, 9/11 widow Kristen Breitweiser's account of the exchange between herself and senior FBI agents, in which she questioned how the FBI managed to identify the very flight school in Florida at which some of the hijackers had trained within hours of the attack, and received the sarcastic retort, "We got lucky." I will keep a close eye on this story as it develops and welcome any new information anyone can provide.