In mid-July 2016, a retired American professor approached an adviser to Donald Trump’s presidential campaign at a symposium about the White House race held at a British university.
The professor took the opportunity to strike up a conversation with Carter Page, whom Trump had named a few months earlier as a foreign policy adviser.
But the professor was more than an academic interested in American politics — he was a longtime U.S. intelligence source. And, at some point in 2016, he began working as a secret informant for the FBI as it investigated Russia’s interference in the campaign, according to people familiar with his activities.
The role played by the source is now at the center of a battle that has pitted President Trump against his own Justice Department and fueled the president’s attacks on the special counsel’s investigation. In a Thursday tweet, he called the probe “a disgusting, illegal and unwarranted Witch Hunt.”
In recent days, Trump and his allies have escalated their claims that the FBI source improperly spied on the campaign.