Democrats Say the Russians Hacked DNC Computers But It’s Not Proven so Why Doesn’t Mueller Go There?

Wasn’t Robert Mueller tasked to investigate Russian meddling in the election and doesn’t Mueller say the Russians hacked the DNC computers? So why doesn’t Mueller prove it by seizing the computers and doing the forensics? The load times of the “hacks” were so quick that experts say it was an inside job, which of course brings to mind Seth Rich at the DNC who favored Bernie Sanders.