WATCH: Rachel Maddow explains why new Mueller filing means big news is coming soon

The host of "The Rachel Maddow Show" on MSNBC explained on Thursday why it appears there will be major developments in special counsel Robert Mueller's investigation -- in the next 10 days.

Maddow reported on a new filing by the special counsel concerning the case of former Donald Trump campaign chairman Paul Manafort.

The special counsel's office had a Friday deadline to update the overseeing judge on Manafort's cooperation with investigators following his guilty pleas.

"And here's the part that makes the ominous music start up in your head and that makes us put the red banner on the bottom of the screen," Maddow said. "In this new report they just filed, Mueller's prosecutors have just asked the judge to please give them 10 days before they tell the judge what's up with Manafort's case right now."

"Ten days? That is very strange," she noted. "They say they're not going to make tomorrow's deadline, they would like a 10 day extension."

"That is unusual," she added.

"What's going to happen in the next 10 days that will give the court a better picture of how helpful Paul Manafort has been?" she wondered. "Something's going to happen between now and 10 days from now that will allow them to be of greater assistance in the court's management of this matter?"

"What's going to happen in the next 10 days?" she asked.

"There is a palpable sense right now that this is the -- this is the time we have been expecting, this is the thing for which we have all been reading up on our history," she concluded.

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