were to testify in front of bob mueller? >> untruthfulness and the possible charge of lying to a federal investigator. >> at the end of the day is it a perjury trap or not? from my perspective, the president shouldn't go anywhere near this group. >> reporter: the tangled tale of russian interference may have started in a london bar in the spring of 20 ken when george papadopoulos a young promoter named to the trump team told moscow had dirt on clinton. >> papadopoulos was the coffee boy. he was and always will be. >> reporter: now after pleading guilty to lying to the fbi as are at least three others. >> when the fbi walks in the room, they're not asking you questions half the time because they want to know the answer. they're asking questions because they want to see what you will say. did you meet with john doe last week, no? well, they got your e-mail. you did. now they know, a, you are not telling the truth. b, they know they have a hammer on you. you just lied to a federal officer. >> reporter: other person under the hammer for lying, deputy campaign chairman rick gates who did business with the russians and worked with campaign chairman paul manafort both before and during the election. manafort could still be under investigation for colluding with russians and has pled not guilty