for today s celebration. the kennedy family has said all along they would rather people honor jfk on his birthday of may 29th, not on the day he died. shannon? casey steeg he will in dallas, thank you. we still don t know some of what the drchlt ia knows about the assassination. correspondent james rosen tells us that fact contributes to the durability of alternative shooting scenarios. the motorcade moves into the downtown area. 50 years after dallas, no serious disputes that oswald killed president kennedy. there are, however, serious scholars who accept that fact but still don t rule out a conspiracy. central to such theorizing is the secretive and deceptive n conduct of the cia which had been tracking oswald since as early as 1959. the warren commission was largely kept in the dark about the cia s monitoring of oswald