News broke last night that Congress was investigating yet another undisclosed meeting between Attorney General Jeff Sessions and Russia ambassador Sergey Kislyak at D.C.'s Mayflower Hotel.

And while he was a guest on The Last Word with Lawrence O'Donnell, Sen. Al Franken last night disclosed he and Sen. Patrick Leahy sent a private letter to then-FBI Director James Comey, asking him to investigate the meeting.

In March, Sessions had gotten into trouble when it was reported that he had two meetings with Kislyak during the campaign, which contradicted statements in his January confirmation hearing. Sessions had testified he did not have any communications with the Russians during the campaign.

Franken said he was aware of a possible meeting at the Mayflower.

"Now it had been characterized one way, but we had some reason to believe that it — that wasn't the case. It had been described in a way that he could plausibly say I don't remember that," Franken said.

"But what's coming out today, I believe, is that that may not be the case. And if this the true, that would be extremely disturbing."

It hasn't been confirmed yet, but it sure sounds like Franken and the other senators know a lot more than they're saying.

P.S. In other news, O'Donnell has renewed his contract and is staying on with MSNBC.