Moreover, one of Padilla's lawyers, Andrew Patel, tells me that the government has ruled that Padilla's attorneys cannot tell anyone what Padilla would say in answer to any government accusations because everything he told his lawyers is classified. Nor could his lawyers ask him about what he said in his interrogations.
http://www.villagevoice.com/issues/0423/hentoff.php

James Comey, therefore, was free to say anything he wanted as he claimed that during the two years of interrogation Padilla "admitted" to certain assignments from Al Qaeda. Also, said Comey, those "admissions" were corroborated by a number of high-level Al Qaeda terrorists who have been interrogated about Padilla while in United States custody. But some of those sources told conflicting stories.

But even the government's documents, to which Comey referred, concede in a footnote, as The New York Sun reported, that "Padilla tried to downplay or deny this commitment to Al Qaeda and the apartment building mission. He said he never pledged an oath of loyalty and was not part of the Al Qaeda. He said he and his accomplice proposed the dirty bomb plot [for which he was first arrested at O'Hare Airport] only as a way to get out of Pakistan and to avoid combat in Afghanistan. He said he returned to America with no intention of carrying out the apartment building operation."