could any of them have travelled to the u.s. what we are learning from talking to counterterrorism officials is that at least one of the paris attackers had a clean enough background he would not have raised any flags and got into the u.s. pretty easily. one of the officials we spoke to said at least three of them would have likely gained entry into the u.s. if they had tried. there is no indication that any of them travelled here at this point in the investigation. we've learned that four of the attackers were in this broad terror day they base and that at least one of them was on the no-fly list. but there is agree it concern among the law enforcement community in the united states that some of them could have slipped through. and also there is disagreement as well, some intelligence officials we have spoken to said we had enough intelligence that would have prevented these attackers from getting into the