general mckenzie was asked whether there was any possibility that the taliban were involved. here's what he said. >> you still trust the taliban and is it possible that they let this happen? >> as to whether or not they let it happen, i don't know. i don't think there's anything that convinces me that they let it happen. >> at this point in time, there's really some differences being made when you talk to u.s. officials about taliban versus isis k and al-quaida. all of the groups are terror groups and they want to kill americans. the problem is finding them. vans full of evacuees, afghans being allowed through the gates on the tarmac. the threat stream is still high.