[ female announcer ] discover what's next in your life. get this free travel bag when you join at aarp.org/jointoday. >>shepard: there seems to have been an assassination in iran, a top scientist would was director of the main nuclear facility is suddenly dead. reportedly murdered. possibly in an effort to set back iran's atomic program. that is what they are saying. the state run news claims two on a motorcycle planted a magnetic bomb on his car f that -- if that is true it is not the first time. a number of other scientists are also dead. the united states and the allies accuser ran of trying to build the bomb that iran says they are not building. and new, in jerusalem, the iranians are blaming the united states. help me understand this. >> well, today, the u.s.