paul manafort, he is facing criminal charges and could go on trial this summer, whether rick gates is needed in that trial. >> i understand the question. it's what kind of information might gates have hadding as is to that mueller would be interested in. >> reporter: right, exactly. there is a lot we don't know about. we know gates worked very closely with paul manafort. even after paul manafort was ousted from the trump campaign, rick gates continued to work with the campaign. he even stayed on, into the inauguration for donald trump. so there is a lot that he was there. he wasn't exactly close inside the inner circle of donald trump, but according to people we've talked to, he very much liked to keep tabs on the comings and goings, he was definitely still associated with the campaign at the time of that trump tower meeting. the meeting where paul manafort was meeting with russia to allegedly get dirt on hillary clinton. so there is a lot he could have for the mueller team.