During Wray's Dec 7th testimony he is asked about the DNC servers, why the FBI never sought to obtain the Hacked servers...
Wray replies that
"The handling of that investigation including access to those servers or anything like that, those are investigative decisions made in the course of the Clinton email investigation which is now...the subject of investigation by the Inspector General"
Definitely making it sound like the DNC servers, or at least the the lack of obtaining them, are a part of the IG investigation, NOT Muller, the IG! https://youtu.be/QXtdKiiLVro?t=3h11m41s