trying to deflect if not stop the investigation of general flynn, involves to some degree the president. i would expect at some point, not right away, at some point mr. mueller feels he has to depose the president. >> reporter: comey's memos which he said he wrote immediately and meetings and phone calls with president trump are now in mueller's possession. those memos could form the basis of expanding the investigation to include the president's alleged asking of comey to back off his investigation of former national security adviser michael flynn, something comey hinted at on thursday. >> do you believe this will rise to obstruction of justice? >> i don't know. that's bob mueller's job to sort that out. >> reporter: appears mueller may also be looking into others around the president. sources tell cnn comey told senators behind closed doors thursday, the fbi has investigated the possibility of an undisclosed third encounter at the play mayflower hotel between kislyak and sessions.