Former White House top strategist Steve Bannon is expected to speak to special counsel Robert Mueller’s team investigating Russian interference in the 2016 election and will tell them “everything” he knows, according to a report on Tuesday.

The special counsel is expected to grill Bannon, who also served as Trump campaign chief for several months during the 2016 election, about his time in the White House, including the firings of former National Security adviser Michael Flynn and former FBI Director James Comey, the Associated Press reported.

The confirmation about Bannon’s meeting with Mueller’s investigators comes as another appearance before the House Intelligence Committee, scheduled for Tuesday, was postponed until next Tuesday.

Bannon was under subpoena to appear, but the hearing was delayed because his lawyer is negotiating with panel members and the White House about what he can discuss, the Associated Press reported.

In a Jan. 16 appearance before the panel, Bannon refused to answer questions about his time in the Trump administration and the transition because the White House may want to claim executive privilege.

A follow-up hearing on Jan. 18 was postponed after Bannon’s lawyers raised concerns about what he could be asked by panel members.

Rep. Adam Schiff, the top Democrat on the House panel, said it is “unacceptable” that Bannon’s appearance before the panel continues to be delayed and threatened to take action to compel him to return next week for an interview.

“Testifying before the special counsel does not obviate Mr. Bannon’s obligations under the subpoena issued by the committee,” Schiff, of California, said in a statement. “Should Bannon maintain his refusal to return and testify fully to all questions, the Committee should begin contempt proceedings to compel his testimony.”

The special counsel is investigating how Russia influenced the election, whether Trump campaign associates colluded and whether Trump tried to obstruct justice by firing Comey, who was then heading up the Russian probe.

Additional reporting by Marisa Schultz