(CNN) Sally Yates, a not widely-known deputy to Loretta Lynch at the Department of Justice, has suddenly become Washington's version of a "person of interest."

Of interest, first, because she got fired for refusing to defend the President's travel ban.

Then it turned out she had a role in the Michael Flynn controversy, so inside the Beltway she's even more interesting.

Yates was scheduled to testify before the House Intelligence Committee about ex-National Security Adviser Flynn's communications with the Russians, but the hearing was mysteriously nixed. GOP committee chairman Rep. Devin Nunes -- who has been the White House's best friend lately -- canceled her appearance without much of an explanation.

She was to be part of a heavy-hitting triumvirate -- including former CIA Director John Brennan and ex-Director of National Intelligence James Clapper -- bringing news about potential Russian connections to the Trump transition.

All in all, a potential triple whammy for the Trump administration, which can't escape the Russia story. Especially after FBI Director James Comey made it clear in public testimony that he's conducting a counterintelligence investigation looking into it.

But back to Yates. She remains clearly willing to testify, as letters revealed by the Washington Post show.

Yates' attorney made it clear in a letter to the Department of Justice that she is legally allowed to speak with the Committee -- aside from not divulging classified information. she would, her attorney made clear, be interested in providing "non-classified facts" about the conduct of a senior White House official -- especially since "multiple senior administration officials have publicly described the same events." (As in: what Gen. Flynn told the White House about his communications with the Russians.)

The Justice Department then passed the buck to the White House counsel, Donald McGahn -- asking for a clear answer by the day before she was scheduled to testify.

None came, but -- surprise -- none was needed: Nunes canceled the hearing. And then, White House press secretary Sean Spicer announced in his briefing that the White House had never asked her to invoke any kind of privilege to avoid testifying.

Except of course, they didn't have to -- since Nunes had already helped them out.

But here's how it could all backfire: Now that Spicer relieved any worries about the privilege matter -- by saying publicly the White House had no interest in invoking privilege -- Yates is likely to testify somewhere, sometime. Indeed Spicer said , "I hope she testifies."

So, what will she say? Multiple sources tell me that she would not have a major revelation to talk about, but the testimony would likely be an "embarrassment" for the White House at the very least.

Why? Because her story differs from the White House on one key point: While my sources say that Yates warned the White House counsel's office of her serious concerns on January 26, that wasn't the public story. Indeed, just the opposite: Both Spicer and Chief of Staff Reince Priebus described her meeting as nothing more than just a "heads up." (In a briefing on February 14, the day after Flynn resigned, Spicer said that Yates did not "come in and say that there was an issue. She said, 'We wanted to give you a heads up that there may be information.'")

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But multiple sources tell me that it was not quite that casual at all. Rather, they say, she had significant concerns that Flynn had been compromised as a result of his conversations with Russians. Flynn said he had not discussed sanctions with the Russian ambassador, and he gave that assurance to Vice President Mike Pence, but it turned out to be a lie.

So, what does that mean? It means Flynn could have been subject to blackmail by Russia.

And, here's the next big question: Why did it take the White House more than two weeks to fire Flynn -- and only after a story appeared in the Washington Post about Flynn's conversations with the Russian ambassador?

Oh, and by the way, they say they didn't fire Flynn because of the content of his conversations, which clearly worried Yates; they fired him because he never told the vice president about them when Pence specifically asked. ("He didn't tell the vice president of the United States the facts and then he didn't remember, and that's just not acceptable," Trump said at a press conference. "I fired him because of what he said to Mike Pence.") Nothing else.

Lying to the vice president is bad idea, but it isn't a crime. And Sally Yates was clearly concerned about something beyond Flynn fibbing to Pence. Sure, administration officials say she gave them nothing more than a heads up.

Hopefully, the public can learn soon whether she, in fact, gave them something much more.

This article has been updated for clarity from an earlier version.