and much to poor bob mueller's chagrin, president bush or the vice-president would say to bob, "so, how are we doing on the anthrax case?" and you could see poor bob mueller's shoulder's slump. he's like, "we're working on it." >> months go by. the case doesn't get immediately resolved because this is a stone-cold whodunit, and so the pressure starts to mount from outside. >> narrator: then, a columnist at "the new york times" entered the fray. >> "i think i know who sent out the anthrax last fall. he is an american insider, a man working in the military bio- weapons field." >> narrator: nicholas kristof began to insist the fbi pursue a man he thought could be the killer, a scientist he called "mr. z." >> he started running column after column, referring to z in various euphemistic ways, but all of us who were on the story knew exactly who he was talking about. >> narrator: according to kristof and others in the media, dr. steven hatfill had access to anthrax when he worked at the army's lab in maryland. >> nick kristof is not small potatoes. he is a well-respected, pulitzer prize-winni

remember fbi director bob mule -- bob mueller is briefing the president every week. remember the ambassador's relationship to the king of saudi arabia makes him a particular target here. i will tell you saudi arabia understood -- has understood very well the capability of the iranians because for the longest time they would not post a saudi ambassador to iraq because they feared for his safety and that he might be targeted by iran inside iraq. so this is -- this capability, this sort of threat is not a shock to saudi arabia. >> fran, if i could just get one more question in. it's brooke. as we're talking about these sanctions issued to these five individuals and jill dougherty reporting from the state department saying they're talking to other countries, we hear attorney general eric holder saying iran will be held accountab accountable. what might that mean? >> when you look at the list of five people targeted with sanctions, this goes and includes the person that was responsible for this operation. what does that tell us? not only was there clearly an informant but

>> bob mueller of the fbi said it was like a hollywood plot. as we've gotten additional details, it's really not only that, but an incredible example of the sophistication and success of the law enforcement agencies here. we know that arbabsiar, the defendant here, flew into mexico and was denied entry. it turns out we've learned tonight from senior counterterrorism official hess was denied entry into mexico by design with the cooperation of the mexican government. he then flew to new york. you might ask yourself why didn't they fly to texas? that's where his family was living. he didn't go to texas because federal officials here in the united states understood that under texas law he may not have been able to be held to do an intelligence interview, so he was flown to new york unbeknownst to the defendant on that flight were federal agents. when that flight landed in new york, federal agents quietly took him into custody, then took him to a u.s. government facility. it was a secret facility where he was held from september 29th until today, th