captioning funded by cbs and ford. we go further, so you can. >> they threatened to hang me. fingernails. they said i'd never see the light of day. >> pelley: it has been nearly a year since alan gross became the lynchpin for the diplomatic breakthrough with cuba. but why was he a prisoner there, and what were those years like? >> i wasn't a spy. >> pelley: this is the first interview with theast prisoner from the cold war. >> this is absolutely ridiculous. "cuba, you want to put your government's eye, go ahead but leave me out of it." >> whitaker: five years ago, when arizona needed drugs to execute an inmate named jeffrey landrigan, it purchased them illelelly from a supplier operating out of this driving school in london.. >> it's my understanding that there was a paperwork issue. the proper forms weren't filled out. >> whitaker: was it used in the execution of mr. landrigan? >> yes.