You have to read to the bottom of Charlie Savage’s New York Times story on Attorney General Holder’s letter to get to this bit:
Meanwhile, officials were bracing for the possibility that WikiLeaks may release yet another cache of leaked United States government documents — this set pertaining to Guantánamo detainees.
After a Reuters article reported that WikiLeaks has the files of every Guantánamo detainee, a government official told The Times that the government believed the claim was correct and that it referred to a set of nearly 800 detainee “threat assessment” files compiled by the Pentagon during the Bush administration.
