to the perpetrator. that's only the start of the equation of course, there will be a lot of learn about that perpetrator's mind-set, his or her motives, linked to other individuals or groups, all of those questions remain to be answered as well. >> in the past there was two very notable cases of attacks via the mail i thought of, uni bomber being one, the other anth anthrax attacks. it's a form of attack people have gotten away. have we gotten better at triesing these things? >> i believe so. of course you're right, some of the other domestic terrorism attacks in recent years have involved individuals with a firearm. it's much easier if someone's willing to, you know, show themselves with a firearm in an attack setting to figure out who the perpetrator is. again, i would argue that the fbi's technical capabilities and the technical ability, the forensic ability of the bureau has advanced significantly in