Robert Mueller has 'dozens of sealed indictments' for people associated with Donald Trump's 2015-16 campaign and his administration, according to an insider who worked with the Special Counsel.

The president this week hired Matthew Whitaker as his Attorney General – a man who previously suggested draining financial resources to limit the probe into the leader in a CNN interview.

However an Intelligence Community official has suggested Mueller already has what he needs.

Robert Mueller has 'dozens of sealed indictments' associated with US President Donald Trump's 2016 presidential campaign

The Russia collusion probe headed by Robert Mueller (pictured) appeared to be under threat when Trump hired Matthew Whitaker

'Nobody who's close to the Russians is getting out of this,' the official told the Observer.

Mueller has been investigating Trump for the past 18 months and quietened down about the probe in the two months leading up to the midterm elections on Tuesday so not to seem to interfere with voting decisions.

He is expected to soon be done with the final draft of his report as to whether Trump's Russian ties helped him in the 2016 presidential elections.

Donald Trump Jr is predicted to be a focus point. The American leader's son is believed to have lied about a meeting with Russian intelligence officials in in June 2016.

He initially said it was about adoptions but changed his tune when talking to the New York Times in July 2017, saying a former 2013 Miss Universe contact had requested a meeting.

It emerged Trump Jr., Jared Kushner and then-campaign manager Paul Manafort, had spoken about alleged links between campaign rival Hillary Clinton and the Russians that could damage her reputation.

But Mueller has 'dozens of sealed indictments' associated with Trump's campaign

Manafort has since been tied to the Kremlin.

'After pleasantries were exchanged,' Trump Jr said, 'the woman stated that she had information that individuals connected to Russia were funding the Democratic National Committee and supporting Mrs. Clinton. Her statements were vague, ambiguous and made no sense. No details or supporting information was provided or even offered. It quickly became clear that she had no meaningful information.'

Matthew Whitaker is Trump's new acting Attorney General. He previously suggested draining financial resources to limit the probe

Mueller could ask to interview the president's son about possibly involving Russia in the election and whether he has obstructed the investigation.

The Special Counsel could also be on the heels of former campaign consultant Roger Stone.

Stone – a friend of the president and Manafort since the 70s – could be linked in various ways to the Russian interference.

Perhaps most notably, he posted Twitter direct messages between himself and alleged Democratic National Committee hacker Guccifer 2.0 on his blog. According to a February 2018 it was operated by Russian military intelligence.

Trump fired his Attorney General Jeff Sessions Wednesday. Sessions had recused himself from overseeing the Mueller investigation.

With concern the acting AG, Whitaker could block Mueller from chasing investigative leads and issuing significant subpoenas, Trump insisted he knew nothing about Whitaker's comments on cutting off investigative resources.

Donald Trump Jr (left) and Roger Stone (right) could be both be focuses in Mueller's investigation

'I don't know Matt Whitaker. He worked for attorney general Sessions,' Trump said at a news conference Friday.

'He was very very highly thought of... It's a shame that no matter who I put in, they go after them.'

'The Russia investigation is a hoax... a phony hoax,' Trump added.

Whitaker's appointment was met with protests in different cities calling for the protection of the Mueller probe.

In radio and television interviews last year, Whitaker repeatedly supported Trump's 'illegal witch hunt' charge against the investigation.

'The left is trying to sow this theory that essentially Russians interfered with the US election, which has been proven false,' Whitaker said in an interview with a conservative Christian broadcaster.

'They are trying to suggest that essentially the Trump campaign had these deep ties into Russia, which is not true.'

Protests erupted in defense of Special Counsel Robert Mueller's Russia collusion investigation after President Donald Trump appointed Mueller critic Matthew Whitaker as acting attorney general

Members of Congress said his appointment was unconstitutional, because he has never been confirmed for top office by the US Senate.

'As an unconfirmed political appointee, Mr Whitaker has not been subject to the scrutiny that the Constitution requires to ensure that he has the character, integrity and ability to fulfil the grave responsibilities of this job,' top Senate Democrat Chuck Schumer said in a letter addressed to Trump Friday.

'These concerns are heightened by specific expressions of bias against the special counsel investigation that Mr Whitaker made just last year,' Schumer said.

Republican Senate chief Mitch McConnell insisted the probe was not under threat and that Whitaker was only a 'very interim' Justice head, while Trump weighs candidates for a permanent attorney general.