actually occurred behind closed doors and what democrats will glean from this as they push ahead on the investigation. wolf? >> manu raju, thank you. the washington post is now reporting that kurt volker told lawmakers today that he warned trump's personal lawyer, rudy giuliani, that allegations against joe biden and his son were simply not credible. rachel, first of all, tell us about that warning that volker gave. >> hey, wolf. i spoke to two sources in the room for volker's testimony. it's still ongoing, obviously. they both told me that volker basically told giuliani that he needed to be careful with this information he was getting from the former ukrainian prosecutors who were pushed out for corruption. obviously, giuliani was hearing all this stuff about joe biden, putting some sort of pressure on them to get rid of an investigation, but volker told him these were not credible sources and he needed to be very careful with the information he was getting. sort of trying to warn him off.