The left-wing newspaper, The Guardian, reported on 11 January, 2017:
John McCain passes dossier alleging secret Trump-Russia contacts to FBI
Julian Borger in Washington
Wednesday 11 January 2017 09.36 EST
The Guardian has learned that the FBI applied for a warrant from the foreign intelligence surveillance (Fisa) court over the summer in order to monitor four members of the Trump team suspected of irregular contacts with Russian officials. The Fisa court turned down the application asking FBI counter-intelligence investigators to narrow its focus. According to one report, the FBI was finally granted a warrant in October, but that has not been confirmed, and it is not clear whether any warrant led to a full investigation.
 The Guardian: “John McCain passes dossier alleging secret Trump-Russia contacts to FBI