DC court clears out entire floor for grand jury hearing in mysterious Mueller case
Robert Mueller in the Oval Office on July 20, 2012. (Photo by Pete Souza.)

Buzzfeed's courts and justice reporter Zoe Tillman is reporting on a secret grand jury proceeding in DC, but it's so secret no one knows what it's about.

Tillman first points to a Politico piece from October: "Mueller link seen in mystery grand jury appeal."

After detailing some court docs as background, Tillman tweets, "They’ve sealed not only the courtroom, but the whole floor." It's getting a lot of attention:

Politico senior reporter confirms:

Here's what some are saying:

Also, this from a Reuters justice reporter: