Perhaps the best example is Mueller’s oddly specific reference to the Russian hackers targeting Hillary Clinton “for the first time” after candidate Trump’s still-unexplained “Russia, if you’re listening” comment on July 27, 2016.
Trump said: “I hope you’re able to find the 30,000 [Clinton] emails that are missing. I think you will probably be rewarded mightily by our press.” (He also said: “I have nothing to do with Russia.”)
A Mueller indictment in July said that the next day, “the Conspirators … attempted after hours to spear-phish for the first time email accounts at a domain hosted by a third-party provider and used by Clinton’s personal office.”
That shows Mueller has access to much more intelligence than is publicly known. Remember, these are Russian government employees. So Mueller has remarkable and thus far unexplained visibility.