In this case, the request for opposition research on Donald Trump came from one of his Republican opponents in the primary campaign. Explainer: what is in the Trump-Russia dossier John McCain passed to the FBI? The original client had dropped out, but the firm that had hired him had found a new, Democratic client. He delivered a set to former colleagues in the FBI, whose counter-intelligence division would be the appropriate body to investigate. However, on 9 December, McCain arranged a one-on-one meeting with Comey, with no aides present, and handed them over.
Source: The Guardian January 11, 2017 17:19 UTC