surreptitiously tape recording conversations. when i heard his plea included information about keeping donald trump's kids up to speed, i have to say, we've heard this before but i was thinking to myself, lordy, i hope there are tapes because we don't know what michael cohen has been taping but we may hear more about that in the future. >> tapes aside, katie, the fact that michael cohen has been proven to lie, he's admitted to doing that, how much does that taint any kind of testimony he has? if you're an attorney and you're trying to get information out of him, how much do you believe what he is saying? zo you have to lo-- do you haveo the motivation? does that challenge anything he says? >> having a flip or having a cooperating defendant is nothing new. you kind of have to take every they say with a grain of salt. but what i suspect with robert mueller in terms of the impeccable way his reputation is