russians or trump and russians. no collusion. bottom line, they all say there is no collusion, and there is no collusion. >> gates is cooperating with mueller, and he is crucial in the investigation h he was manafort's right hand man and had intimate knowledge what was going on inside the campaign. as one person with knowledge of the situation said of gates, he was an implementer. the alleged russian intelligence agent is referred to as a in court documents, but we understand it is constantine who once worked foreman a fort and lived in moscow and ki kiev according to sources close to the investigation. what could they know? >> reporter: they believe they could have information valuable beyond business partner paul manafort who is also the campaign chairman. one of the things sources were telling my colleague, caitlyn,