bob grenier, the cia's former head of counter-terrorism, told us what they found. >> grenier: there wasinvestigation, which included multiple polygraph examinations. >> pelley: what was the conclusion in nada prouty's case? >> grenier: she was completely exonerated. >> pelley: the cia wrote this letter to the prosecutors saying, "the agency did not identify any information that mrs. prouty cooperated or engaged in unauthorized contact with a foreign intelligence service or terrorist organization." how seriously do they take those investigations? how thorough are they? >> grenier: oh, my god, you cannot imagine how seriously the cia would take an investigation like that. >> pelley: at sentencing, federal judge avern cohn blasted the u.s. attorney's office. "perhaps prompted by the excessiveness of the press releases," he said, the news media "grossly distorted the circumstances of your case." "as a citizen," the judge told prouty, "you served your country honorably and effectively." but because of the law, the judge was forced to revoke her citizenship. instead of throwing her in prison,