"treasonous"

That Special Counsel Robert Mueller is becoming rattled because of the growing criticism of his investigation by Republicans in Congress and because of the legal action Paul Manafort has recently brought against him, is strongly suggested by his frankly very strange decision not just to subpoena Steve Bannon but to subpoena Steve Bannon to give evidence before a Grand Jury.
It is difficult to understand the logic of this step if Mueller is carrying out a serious investigation.