Bush's Desaparecidos

We know the fate of some torture victims who were named "enemy combatants" by president George W. Bush. But there are over three dozen human beings in that category who seem to have disappeared altogether. ProPublica:

Last week, we pointed out that one of the newly released Bush-era memos inadvertently confirmed that the CIA held an al-Qaeda suspect [1] named Hassan Ghul in a secret prison and subjected him to what Bush administration lawyers called "enhanced interrogation techniques." The CIA has never acknowledged holding Ghul, and his whereabouts today are secret.

But Ghul is not the only such prisoner who remains missing. At least three dozen others who were held in the CIA's secret prisons overseas appear to be missing as well. Efforts by human rights organizations to track their whereabouts have been unsuccessful, and no foreign governments have acknowledged holding them. (See the full list. [2])

What happened to these people? What was done to them?