There was no "federal agent". The investigator working for Fox, the Police, and the Rich family lawyer all said there was never a federal agent involved. Other right wing media have also dropped the story after it fell apart. One guy was persisting saying that he had contact with Kim.com who was the hacker who helped Seth get emails to Wikileaks-- that would be enough for anyone to drop the story. By the way Fox has dropped several other stories-- the most recent was the story that British agents tapped Trump's phone and fed recordings to Obama.