National Security Adviser Mike Flynn resigned late on Monday after just 25 days on the job. The Trump administration was facing increasing pressure over Flynn’s contacts with Russia in the waning days of the Obama presidency before Trump took office. Flynn initially denied discussing Obama administration sanctions placed on Russia during his correspondence with Russian Ambassador Sergey Kislyak, but over the past month new evidence trickled out contradicting Flynn’s claims and raising questions about whether he had lied to the vice president about the nature of his Russian interactions and what the president and his top advisers knew.

In his resignation letter, Flynn did not say whether he discussed sanctions with Kislyak but admitted to not being truthful with Pence about the conversations. “Unfortunately, because of the fast pace of events, I inadvertently briefed the Vice President Elect and others with incomplete information regarding my phone calls with the Russian Ambassador,” Flynn wrote. “I have sincerely apologized to the President and Vice President, and they have accepted my apology.”*

Earlier on Monday, the Washington Post wrote a nice tick-tock of what we know about Flynn’s shifting story on his Russia call that lead to his resignation:

Word of the calls leaked out on Jan. 12 in an op-ed by Post columnist David Ignatius. “What did Flynn say, and did it undercut U.S. sanctions?” Ignatius wrote, citing the Logan Act. The next day, a Trump transition official told The Post, “I can tell you that during his call, sanctions were not discussed whatsoever …”

White House press secretary Sean Spicer, in a conference call with reporters on Jan. 13, said that the conversation between Flynn and Kislyak had “centered on the logistics” of a post-inauguration call between Trump and Putin. “That was it, plain and simple,” Spicer added.

On Jan. 15, Pence was asked about the phone call during an appearance on CBS’s “Face the Nation.” Citing a conversation he had with Flynn, Pence said the incoming national security adviser and Kislyak “did not discuss anything having to do with the United States’ decision to expel diplomats or impose censure against Russia …”

In a Feb. 8 interview with The Washington Post, Flynn categorically denied discussing sanctions with Russian Ambassador Sergey Kislyak, repeating public assertions made in January by top Trump officials. One day after the interview, Flynn revised his account, telling The Post through a spokesman that he “couldn’t be certain that the topic never came up.”

The resignation of Flynn, a staunch and vocal advocate for Trump throughout the campaign, will likely shift the focus away from the embattled adviser and toward the president and what role he may have had in directing or approving of Flynn’s going behind the back of the sitting American president’s foreign policy.

Breaking: text of Flynn's resignation letter pic.twitter.com/KGue1cJFzL — Zeke Miller (@ZekeJMiller) February 14, 2017

*Correction, Feb. 14, 2017: This post originally misquoted Flynn’s resignation letter as saying he initially gave Pence an incomplete briefing because of the “past pace of events.” He wrote it was because of the “fast pace of events.”