Closing In On What?

I'm of course open to the idea that zealous prosecutors can make life miserable for people who really didn't do anything wrong, possibly justified as necessary in the course of trying to get the actual wrongdoers. But if people are freaking out, it's fair to ask...just what are they freaking out about?

But Trump’s anger Monday was visible to those who interacted with him, and the mood in the corridors of the White House was one of weariness and fear of the unknown. As the president groused upstairs, many staffers — some of whom have hired lawyers to help them navigate Mueller’s investigation — privately speculated about where the special counsel might turn next.

“The walls are closing in,” said one senior Republican in close contact with top staffers who spoke on the condition of anonymity to speak candidly. “Everyone is freaking out.”