Where the "FBI spy in the Trump campaign" story came from
President Trump has grown increasingly convinced that the FBI used an informant to spy on his 2016 campaign, and has now demanded a Justice Department investigation:
The back story: There has been a growing amount of speculation by conservative writers that an FBI source spied on the Trump campaign, and might have even planted a spy inside. It's now clear from multiple news reports that the FBI had an informant who talked to two campaign advisers, but not that the informant was planted on the inside. That talk is based on suspicions — not evidence.