let's go now to the russia investigation. a new insight into some of the tactics russian spies may have used. a new book makes the case that russia may have collected compromising information on president trump decades ago. here's what luke harding, the author of the new book "collusion: collusion, dirty money and how the russians helped donald trump win told me about his findings. >> in your writes you said research led you to ask whether or not moscow was mailing president trump. what made you suspicious of that? >> i think so much of the story is in plain sight, saying, russia, if you're listening, find the 33,000 e-mails, which are not there. you also have a long history of engagement. trump first visited moscow in the summer of 1987 and who invited him? the soviet government. they don't do that for everybody. who organized his trial?