Robert Mueller is either a fool, or deeply corrupt. I do not think he is a fool.
There has never been, by any US law enforcement or security service body, a forensic examination of the DNC servers, despite the fact that the claim those servers were hacked is the very heart of the entire investigation. Instead, the security services simply accepted the “evidence” provided by the DNC’s own IT security consultants, Crowdstrike, a company which is politically aligned to the Clintons.
That is precisely the equivalent of the police receiving a phone call saying:
“Hello? My husband has just been murdered. He had a knife in his back with the initials of the Russian man who lives next door engraved on it in Cyrillic script. I have employed a private detective who will send you photos of the body and the knife. No, you don’t need to see either of them.”