Well.. he was to a certain degree.
Not at all. Mueller has a long swampy history.
He found Trump NOT GUILTY of any collusion and has refused to testify in any followup hearings so far.
Mueller won't testify because he is afraid of Nunes. Mueller did Trump no favors with his report and his witch hunt investigation. It wasn't until Trump built enough leverage against Mueller, that he ended the investigation.
"The dogs bark but the caravan moves on."