WASHINGTON — In the weeks after Donald Trump became the Republican nominee in late July 2016, the FBI warned him that foreign adversaries, including Russia, would attempt to spy on and infiltrate his campaign.
It was a standard briefing, the kind routinely given to presidential candidates, capped with an admonition that Trump should call the FBI if he learned of any unusual approaches from foreigners.
But there was something the FBI didn’t tell him.
The bureau just recently had opened counterintelligence investigations into four Trump advisers suspected of improper interactions with Russians — a fact, then-secret, that emerged much later in Congressional testimony.
Source: Trump and Russia: What to expect from Mueller in 2019 : NBC News