Friday was one of those times, as Mr. Mueller and his team indicted 12 Russian military intelligence officers for allegedly hacking into the Democratic National Committee and the Hillary Clinton campaign.
The Russians are accused of breaking into the computer networks of several organizations of the Democratic Party to steal emails.
In February, Mueller charged 13 Russians and three Russian companies in an elaborate conspiracy to interfere in the election.
The charges come as Mr Mueller continues to investigate potential coordination between Russian Federation and the Trump campaign to influence the presidential election.
The charges come just days before President Donald Trump is set to meet with Russia's President Vladimir Putin and on the same day that Trump, on a trip to the United Kingdom, again called the investigation a "witch hunt".
Attorney Ken White, a former federal prosecutor, weighs Trump's comments and the apparent Russian reaction and wonders if what he said might amount to aiding and abetting a crime.
The indictment says that Florida elections officials were targets of the operatives, who worked for the Russian foreign intelligence service, the GRU.More news: Fortnite Season 5 is finally here - here are the biggest changes
It was the most detailed United States accusation yet that Russian Federation meddled in the election with the eventual aim of trying to boost Republican Trump's campaign.
Rosenstein said he has already briefed the president on the content of the indictment.
Trump said he did not know who was orchestrating the election hacking but suggested it was "probably China", adding that if it was hypothetically Russian Federation intelligence, it would show their lack of reverence for the United States.
Hours before the Justice Department announcement, Mr Trump complained anew that the special counsel's investigation is complicating his efforts to forge a better working relationship with Russian Federation.
He said the indictments were "further proof of what everyone but the President seems to understand - President Putin is an adversary who interfered in our elections to help President Trump win".
Hours later, the Main Intelligence Directorate in Moscow appeared to heed the call - targeting Clinton's personal office and hitting more than 70 other Clinton campaign accounts.
"The goal of the conspiracy was to have an impact on the election", Rosenstein said. "This exchange is entirely public and provides no evidence of collaboration or collusion with Guccifer 2.0 or anyone else in the alleged hacking of the DNC emails, as well as taking place many weeks after the events described in today's indictment".
After the indictments were announced, top Senate Democrat Chuck Schumer called on Trump to cancel his meeting with Putin until Russian Federation takes steps to prove it won't interfere in future elections. "We would have a chance to have ... a very good relationship with President Putin".