Washington (CNN) On Monday afternoon, acting Attorney General Matt Whitaker gave us a surprising window into special counsel Robert Mueller's investigation into Russian interference in the 2016 election.

"I've been fully briefed on the investigation and, you know, I look forward to Director Mueller delivering the final report," said Whitaker. "But right now, you know, the investigation is -- I think, close to being completed. And I hope that we can get the report from Director Mueller as soon as we -- as possible."

OK, there's definitely some wiggle room there -- "I think" and "I hope" -- but the big takeaway is this: The top law enforcement officer in the country just said that he has been "fully briefed" on Mueller's investigation and that he thinks it is "close to being completed." It's not definitive, of course, but it's the clearest sign yet we've had from someone in a position to know that Mueller is in the final stages of the probe.

Given that there's every reason to think that Whitaker is in a position to know where the Mueller investigation stands, it's worth trying to game out -- as best as we can -- when the report could drop.

Before we do that, here's where we've been on this whole thing.