More bad news for Donald Trump as Facebook CEO Mark Zuckerberg confirms that his company is working with special counsel Robert Mueller, saying, “I know we’re working with them.” So much for Trump blathering on that there’s nothing there.

Zuckerberg told the senators that he has not been interviewed by Mueller’s team but other Facebook officials have been interviewed.

Here’s the exchange between Sen. Patrick Leahy (D-VT) and Zuckerberg:

Sen. Patrick Leahy: I assume Facebook has been served subpoenas is that correct?

Mark Zuckerberg: Yes.

Leahy: Have you or anyone at Facebook been interviewed by the special counsel’s office?

Zuckerberg: Yes.

Leahy: Have you been interviewed?

Zuckerberg: I have not. I have not —

Leahy: Others have?

Zuckerberg: I believe so. I want to be careful here. Because that — our work with the special counsel is confidential. I want to make sure in an open session I don’t reveal something that’s confidential.

Leahy: I understand. I just want to make clear that you’ve been contacted and have had subpoenas?

Zuckerberg: Actually, let me clarify that. I actually am not aware of a subpoena. I believe there may be, but I know we’re working with them.

Watch the exchange:

This is a really, really big deal. Michael Cohen isn’t the only worry Donald Trump has, the Mueller investigation is ramping up and that has him cornered.