Mike Flynn concealed his fateful FBI interview from Trump White House -- until Yates blew the whistle: report
President Donald Trump, Mike Flynn, Reince Priebus, Mike Pence and Steve Bannon (Sean Spicer, White House.gov)

One year ago today, then-national security adviser Mike Flynn met privately in his West Wing office for an interview with FBI agents about his communications with the Russian ambassador.

Flynn answered questions without a lawyer present and without telling President Donald Trump or other top White House officials -- and more than 10 months later pleaded guilty to lying during that Jan. 24, 2017, interview, reported NBC News.

Two people familiar with the matter told NBC News that Trump learned two days after the interview that Flynn had spoken with the FBI, which was set up hours before it took place by deputy FBI director Dan McCabe and a White House scheduler.

The scheduler didn't ask the reason for the meeting and the FBI didn't offer an explanation, one source told NBC News.

No one knew that any of this was happening," said another senior White House official who was in the administration at the time.

"Apparently it was not clear to Flynn that this was about his personal conduct," said a second White House official. "So he didn't think of bringing his own lawyer."

Two days after the interview, then-deputy attorney general Sally Yates warned White House counsel Don McGahn that Flynn may be vulnerable to blackmail by the Russian government because he had lied to top White House officials, including Vice President Mike Pence.

McGahn briefed Trump, along with then-White House chief strategist Steve Bannon and then-chief of staff Reince Priebus, about his meeting with Yates later that same day.

That's when Trump learned Flynn had been interviewed with the FBI, sources told NBC News.

Yates, who was fired Jan. 30, has testified before Congress that McGahn asked her how Flynn had done in his interview, and she said she told the White House counsel she could not comment on that.

A source said McGahn did not ask Flynn if he had lied to the FBI, but they said it's not clear whether the White House counsel suspected the national security adviser had misled investigators.

The FBI requested Flynn's phone records and other documents in late winter, after Flynn was forced out.

A source told NBC News the White House concluded at that time that Flynn had lied in his interview and was under investigation -- so the president would have known his national security adviser was in legal jeopardy when he fired FBI director James Comey on May 9.

Comey has testified before lawmakers that Trump asked him Feb. 14, the day after the national security adviser's firing, to let go of his investigation of Flynn, but the president has denied that allegation.

That timeline will be key to proving a possible obstruction of justice case against the president in special counsel Robert Mueller's investigation.

Comey was interviewed late last month by Mueller's team.