'He turned on me': Trump became enraged and 'hurt' that Flynn appeared to have flipped weeks before his guilty plea
Michael Flynn, Donald Trump -- screenshots

Three sources close to the White House confirmed that in recent weeks, President Donald Trump fumed in private over the now-confirmed assumption that his one-time national security adviser Mike Flynn would flip on him.

According to those sources, who spoke to The Daily Beast on condition of anonymity, news reports in recent weeks caused the president to fear that Flynn "turned on" him.

"Trump’s fears came into sharp focus this past month, as several media outlets began to report that Flynn appeared to be cooperating with special counsel Robert Mueller’s investigation into alleged Russian meddling in the 2016 election," the report reads.

The Beast's sources, which include one person within the administration and two people close to the president outside the White House, said the president "began privately fuming" at the concept. Two of those sources also said "it sounded at times as if Trump felt personally hurt by the prospect that someone whom he admired professionally and liked personally had potentially turned."

On Friday, Flynn pleaded guilty to lying to FBI officials about his contacts with Russian officials, and is expected to deliver testimony that could be harmful to Trump and his family.