Republican Congressman Jim Jordan slammed Robert Mueller Wednesday over suspected spy Joseph Mifsud's role in the Russia probe and asked why he was never charged with a crime.

Jordan pressed the special counsel about the mysterious Russia-linked professor Joseph Mifsud, who, at one point, was rumored to be either dead or living in hiding, and his relationship with former Trump campaign foreign policy aide George Papadopoulos.

Mifsud is said to be the one who told Papadopoulos during the 2016 campaign that the Russians had 'dirt' on Hillary Clinton - a conversation that would lead to the FSIA warrant against former Trump campaign aide Carter Page to investigate whether or not he was a Russian spy.

Jordan, one of President Donald Trump's biggest defenders on Capitol Hill, pointed out Mueller, in his own report, said Joseph lied to the FBI.

Republican Congressman Jim Jordan slammed Robert Mueller over suspected spy Joseph Mifsud's role in the Russia probe

Robert Mueller said he couldn't talk about internal decisions made in the investigation

'Three times he lied to the FBI. Yet you didn't charge him with a crime. Why not?,' Jordan demanded.

'I can't get into internal deliberations with regard to who would or would not be,' Mueller began to answer before Jordan interrupted him.

'You charged a lot of other people for making false statements,' Jordan said.

He went on to point out the FBI 'spied' on Papadopoulos and Page.

While Page was subject to the court-approved FISA warrant, Papadopolous was spied on, Jordan argued, with 'human sources.'

He accused the FBI of using people like former CIA operative Stefan Halper and even a 'lady posing as someone else' to spy on Papadopoulos.

Jordan pointed out it was Mifsud who told Papadoulos that the Russians had Clinton.

'This is the guy who told Papadopoulos and the guy who starts it all,' Jordan said yelling loudly during the hearing.

He went on to list the others Mueller charged with lying including former Trump campaign manager Paul Manafort, Manafort's deputy Rick Gates, former Trump personal attorney Michael Cohen and former National Security Adviser Michael Flynn.

'When the F.B.I. Interviews him he lies three times and yet you don't charge him with a crime. You charge Rick Gates for false statements, Paul Manafort for false statements, Michael Cohen with false statements, you charge Michael Flynn, three-star general with false statements but the guy who puts the country through this whole saga, starts it all for three years we've lived this now, he lies, and you guys don't charge him. I'm curious as to why?' Jordan asked.

Mueller refused to be budged in his response.

'I can't get into it and it's obvious we can't get into charging decisions,' he said.

Jordan inquired if Mifsud lied to the special counsel's investigation too.

'Can't get into that,' Mueller responded.

He refused to confirm whether or not his investigators talked to professor.

Professor Joseph Mifsud has not been seen or heard from since November 2017

Mifsud told Trump campaign adviser George Papadopoulos the Russians had 'dirt' on Hillary Clinton

'A lot of things you can't get into,' Jordan snapped back. 'You can charge 13 Russians no one has ever heard, seen or you can charge them and all kinds of people around the president with false statements, but the guy who launches everything, the guy who puts this whole story in motion, you can't charge him. I think that's amazing.'

'I'm not certain I agree with your characterizations,' Mueller responded.

The Mueller report states it was lies that Papadopouos told the FBI that hurt their investigation and their time with Mifsud: 'The false information and omissions in Papadopoulos's January 2017 interview undermined investigators' ability to challenge Mifsud when he made these inaccurate statements.'

Jordan's line of questioning follow a report in The Hill newspaper that the Justice Department was trying to get ahold of Misfud as part of their probe into how the FBI's counterintelligence investigation of Trump's campaign began.

In September, Papadopoulos was sentenced to two weeks in jail Friday for lying to the FBI during the Russia probe.

He became the the first member of Trump's campaign team to be sentenced in Mueller's investigation.

Among the things Papadopoulos lied about to FBI agents under questioning was his contact with Maltese London-based professor Joseph Mifsud, who said the Russians had 'dirt' on Hillary Clinton.

George Papadopoulos and his wife Simona Mangiante

The Papadopoulos-Mifsud relationship was examined by Mueller as another opportunity to see if there was collusion between Trump's team and Moscow.

Papadopoulos made contacts with Mifsud, who claimed Kremlin links and introduced him to other ostensibly well-connected Russians, including an alleged niece of Russian President Vladimir Putin.

Papadopoulos suggested to the Trump campaign team that Trump and Putin should meet and pursued setting up such a sit down.

At a breakfast on April 26, 2016, in London, Mifsud told Papadopoulos that people in Moscow had 'dirt' on Clinton - information Papadopoulos later shared with the campaign.

In May of 2016 - also in London - Papadopoulos told the top Australian diplomat to the United Kingdom, Alexander Downer, that Russia was in possession of emails relating to Clinton.

In July, after the DNC hacking had become public, the Australians told U.S. authorities about Papadopoulos's comment, leading the FBI to open a counterintelligence investigation into Trump's campaign in July of 2016.

The DNC has attempted to track down Mifsud as part of their investigation into the hacking of their emails.

In the fall of last year, Mifsud was thought to be dead or living in hiding.

Mifsud has not been seen or heard from since November 2017, just after Mueller revealed that Papadopoulos had pleaded guilty to lying to the FBI about his contacts with the professor.

Some reports have him living in Rome.

He was interviewed by the FBI in February 2017 while visiting the United States to speak at a conference.

Joseph Mifsud has been said to be dead or living in hiding

In September lawyers for the DNC suggested Mifsud may be dead but one of his friends, who co-owns Link Campus University in Rome, where Mifsud once taught, said he was alive.

The DNC, which is suing Russia, the Trump campaign and WikiLeaks for interfering in the 2016 election, said in a court filing in September that it believes all the defendants in the case have been served 'with the exception of Mifsud (who is missing and may be deceased).' The lawyers didn't elaborate.

In his interview with ABC News last fall, Papadopoulos detailed his work on the Trump campaign, including a proposed meeting between the then-presidential candidate and Putin and his contact with Mifsud.

Papadopoulos said after a Trump campaign meeting in March, where he suggested a meeting between Trump and Putin, he sought to use his connection to Mifsud to arrange the sit down.

'The campaign was fully aware with what I was doing, including Corey Lewandowski, Sam Clovis,' he said of his fellow Trump campaign advisers. 'I was actively discussing with the group and Sam that I was talking with Mifsud and that this person could potentially organize a meeting for us with Putin.

Papadopoulos said he met with Mifsud in April 2016 at the Andaz hotel by Liverpool Street Station in London.

And that meeting was where Mifsud, who had been in Moscow the week before where he'd had meetings with the Russian parliament, revealed he knew of the existence of some emails hacked from Hillary Clinton's campaign.

'He sat me down and he was quite giddy. And he told me, I have information that the Russians have thousands of Hillary Clinton's e-mails,' he said.

Former Donald Trump presidential campaign foreign policy adviser George Papadopoulos spent 12 days in prison after pleading guilty to lying to the FBI

Mifsud introduced Papadopoulos, a new Trump foreign policy advisor, to his associate Olga Polonskaya. He also introduced Papadopoulos to Ivan Timofeev of the Russian International Affairs Council.

'During the interview, Papadopoulos lied about the timing, extent, and nature of his communications with Joseph Mifsud, Olga Polonskaya, and Ivan Timofeev,' according to Mueller's report.

Papadopoulos emailed the Trump campaign after his London sitdown with Mifsud.

The subject heading of his first email was: "Meeting with Russian leadership--including Putin.'

'I just finished a very productive lunch with a good friend of mine, Joseph Mifsud, the director of the London Academy of Diplomacy – who introduced me to both Putin's niece and the Russian Ambassador in London – who also acts as the Deputy Foreign Minister,' Papadopoulos wrote.

'They said the leadership, including Putin, is ready to meet with us and Mr. Trump should there be interest,' he added.

However, the Mueller report noted: 'Papadopoulos's statements to the Campaign were false. As noted above, the woman he met was not Putin's niece, he had not met the Russian Ambassador in London, and the Ambassador did not also serve as Russia's Deputy Foreign Minister.'

His internet search history reveals he tried to run down the false information about Mifsud's associate being Putin's niece. He searched terms including 'putin's niece,' 'olga putin,' and 'russian president niece olga', among other terms, according to the report.

Robert Mueller would not even confirm if his investigators talked to Misfud

Papadopoulos repeatedly contacted the Trump campaign about a potential Trump-Putin meeting that never happened

The efforts to arrange a Trump-Putin meeting extended through the spring and summer. 'Throughout that period of time and for several months thereafter, Papadopoulos worked with Mifsud and two Russian nationals to arrange a meeting between the Campaign and the Russian government. No meeting took place.

Papadopoulos said he originally met Mifsud at a conference in Rome when he was there for his work with the London Center of International Law Practice, shortly before he joined the Trump campaign.

He said he told Mifsud he was going to work for Trump.

'He basically presented himself as this well-connected, well-traveled former diplomat who could essentially connect me and the campaign to Russian officials and to other leaders around the world,' Papadopoulos told ABC News last year.

The contact among the two men was among the numerous threads the Mueller team sought to untangle of Russian efforts to approach Trump campaign officials.

Tying some of this together is Cambridge professor Stefan Halper, who was an FBI informant who approached Page and Papadopoulos about any potential ties to Russia as part of the agency's counter-intelligence investigation.

Page has denied being a Russian spy.

Republicans argue that evidence the FBI used to obtain the FISA warrant on Page came from unverifiable sources such as the infamous Christopher Steele dossier, which had unverified allegations that the Russians had blackmail information on Trump and was paid for by a law firm that also did work for the Democratic National Committee.