Special counsel Robert Mueller (2nd L) leaves after a closed meeting with members of the Senate Judiciary Committee June 21, 2017 at the Capitol in Washington, DC.

Special Counsel Robert Mueller is building a case against the Russians who hacked and leaked private information of several key Democrats during the 2016 election, NBC News reported.

These new charges rely heavily on intelligence gathered by the CIA, the FBI, the National Security Agency (NSA) and the Department of Homeland Security (DHS), and target a different group of Russian actors than those indicted last month, according to NBC.

A possible new indictment would include details on the Russian intelligence operation that released emails stolen from both the Democratic National Committee (DNC) and Clinton campaign chairman John Podesta, NBC reported. Democratic emails made public through website Wikileaks factored heavily in the 2016 election, embarrassing Democrats and adding fuel to the Trump campaign.

Sources told NBC News that Mueller has long had sufficient evidence to make a case, but has been waiting for a strategic moment.

Mueller's team has reportedly asked witnesses whether Trump was aware that the emails he repeatedly referenced throughout his campaign had been stolen and whether he was involved in their release, according to NBC News.

President Trump has repeatedly denied collusion with Russian intelligence actors.

Read more about Special Counsel Robert Mueller's investigation from NBC News.