now they have cooperating witnesses, michael flynn would be really key in that who has told the prosecutors if you charge me with a light crime i'll tell you everything you need to know. and that's always part of the deal. that -- you know they're working him to death getting ready for the bigger interviews. that's normally the end. 95% of the time, don, i'd be surprised if that weren't a wrap-up at least on a portion of the investigation. >> um-hum. cnn has learned also that attorney general jeff sessions met with mueller's team for several hours last week. what value is -- what value is in his testimony? >> pretty significant. so he was very active on the campaign. he was very active on the -- as the national security adviser for the campaign. and then he switched over to the transition team later. so he would have been involved in lots of those discussions. along with michael flynn, bannon and others on the campaign. so his testimony would be very,