go long. we're following breaking news in the san bernardino terror investigation. just a while ago the fbi revealed significant new details about the two killers. >> as the investigation has progressed, we have learned and believe that both subjects were radicalized and have been for quite some time. now, how did that happen? the question we're trying to get at is how did that happen and by whom and where did that happen. and i will tell you right now we don't know those answers at this point. >> let's bring in our justice reporter evan perez following the investigation. what do you think led the fbi to reach this sort of interim conclusion? >> well, wolf, they've had a little time to go through his communications, to find -- to talk to members of the family. and my understanding is they found that this radicalization path is not something that just