Mueller has evidence that Trump supporter's meeting with Putin ally may not have been a chance encounter: Sources Sources say a key witness has told investigators he set up the meeting.

Special Counsel Robert Mueller has obtained evidence that calls into question Congressional testimony given by Trump supporter and Blackwater founder Erik Prince last year, when he described a meeting in Seychelles with a Russian financier close to Vladimir Putin as a casual chance encounter “over a beer,” sources told ABC News.

Well-connected Lebanese-American businessman George Nader, a key witness given limited immunity by Mueller, has been interviewed seven times by prosecutors on a wide range of subjects. He told investigators that he set up a meeting in the Seychelles between Prince and Russian sovereign wealth fund CEO Kirill Dmitriev, mere days before Trump was inaugurated, sources familiar with the investigation said this week.

Nader has submitted to three interviews with special counsel investigators and four appearances before a federal grand jury in Washington since agents stopped him at Dulles International Airport in January, served him with a grand jury subpoena and seized his electronic devices, including his cell phone. Documents obtained by Mueller suggest that before and after Prince met Nader in New York a week before the trip to the Seychelles, Nader shared information with Prince about Dmitriev, sources familiar with the investigation told ABC News, which appears to be inconsistent with Prince’s sworn testimony before a U.S. House of Representatives investigative panel.

"I didn't fly there to meet any Russian guy," Prince told the House Permanent Select Committee on Intelligence in November. He testified that he travelled to the Seychelles for a meeting with United Arab Emirates officials about possible business opportunities, and they introduced him – unexpectedly – to Dmitriev.

The special counsel's office declined to comment on this story when reached by ABC News.

As of late March, Mueller’s team has not asked Prince – whose sister Betsy DeVos serves as Trump’s Secretary of Education – to appear before the grand jury being used to investigate whether Trump campaign officials or transition aides colluded with Russian government operatives, according to one of Prince’s friends.

Prince told the House Intelligence Committee that his meeting with Dmitriev was a chance encounter “down in the bar” at the suggestion of "one of the brothers" of the United Arab Emirates' leader Crown Prince Mohammed Bin Zayed al-Nayhan.

"At the end, one of the entourage says, 'Hey, by the way, there’s this Russian guy that we’ve dealt with in the past. He’s here also to see someone from the Emirati delegation. And you should meet him. He'd be an interesting guy for you to know, since you’re doing a lot in the oil and gas and mineral space,’” Prince told lawmakers under oath in his sworn testimony. “So, as I recall, I met him, this same guy I talked about, Kirill Dmitriev. Met him down in the bar after dinner, and we talked for 30 minutes over a beer, and that was it.”

Sources say Nader -- who worked at the time for the Emirati leader, known as "MBZ” – tells a different story. According to multiple sources, the U.A.E., an important U.S. ally increasingly eager to be seen as a global powerbroker, wanted to bring a Russian close to the Kremlin together with someone Nader believed was a trusted confidant of members of the incoming administration.

Sources tell ABC News Nader met with Prince at New York's Pierre Hotel a week before the Jan. 11, 2017 meeting in the Seychelles, and later sent Prince biographical information about Dmitriev, which, according to those sources, noted that Dmitriev had been appointed by Putin to oversee the state-run sovereign wealth fund.

Nader says he then facilitated and personally attended the meetings, including one between Prince and Dmitriev, at a resort owned by MBZ off the coast of East Africa, the sources told ABC News. One of the primary goals of the meeting, Nader told investigators, was to discuss foreign policy and to establish a line of communication between the Russian government and the incoming Trump administration, sources told ABC News.

Nader — who Prince said in a 2010 lawsuit deposition had once represented his military contractor business in Iraq — was not mentioned in Prince's congressional testimony despite Prince being asked by lawmakers who was present. Prince said only that Dmitriev's wife was there but she left after a few minutes while they discussed terrorism and oil prices.

A spokesperson for Prince told ABC News on Thursday that "Erik has said all there is to say to the committee and has nothing further to add." Prince has said that the Seychelles meeting was leaked to the news media last year in an illegal “unmasking” of his identity in U.S. signals intelligence intercepts.

Nader, a naturalized U.S. citizen, is an enigma in the nearly yearlong probe of the Trump presidential campaign's dealings with Russians linked to the Kremlin.

His background and credibility have come under attack as his name appeared in recent headlines. He has been arrested twice in the U.S., first in 1984 and again 1991, and convicted once, according to court records unsealed in March, for possession of pornographic videos featuring underage boys.

Nader was also arrested for similar charges involving underage boys in the Czech Republic, according to an Associated Press report.

ABC News could not confirm the AP report, and Nader’s legal team vigorously disputes its accuracy.

Nader's lawyers at powerhouse firm Latham & Watkins, which includes former Obama White House Counsel Kathryn Ruemmler, have said unnamed individuals are dredging up the old criminal cases to discredit him as an important witness for Mueller. They declined to comment to ABC News on Nader's interactions with the special counsel and Nader himself has refused to speak about the Russia probe.

Few in Washington remember George Nader, whose colorful biography reads like a spy thriller: his career has spanned the globe, and along the way he has been a hostage negotiator, arms broker, security operative and, now, an important witness for the former director of the FBI.

He’s even negotiated with the Kremlin. According to Al-Monitor, a news website covering the Middle East, Nader helped broker a $4.2 billion arms deal between Iraq and Russia in 2012.

Nader’s associates say he has embarked on countless sensitive diplomatic missions overseas and was once a special adviser to Vice President Dick Cheney. He had easy access to the White House under Presidents Reagan, both Bushes and Clinton, according to former officials, and he visited the Trump White House last year despite his criminal record.

Nader posed with Trump for a picture and even helped arrange the new American president's first major foreign trip to the Kingdom of Saudi Arabia last year, two top Trump advisers told ABC News.

"He has worked for the Israelis, the Syrians, the Iranians, the Saudis, the Emiratis, the Shiites in southern Iraq," said Mouafac Harb, a Lebanese former journalist who has known Nader for decades. "He’s typical of the kind of shady operatives you often see in the Middle East.”

His 1991 federal conviction in Alexandria, Virginia, for being caught returning from Germany with videotapes in his luggage "depicting minors engaged in sexually explicit conduct" highlights the conflicting chapters in his life.

Prominent foreign policy figures sent testimonials to the federal trial court judge in Virginia, including one friend who said Nader, a Lebanese Christian, "is risking his life" to help free a dozen American, British and other hostages held in Beirut in 1991, by leveraging his close ties to the Shi'a terrorist group Hezbollah. The letters to the judge were provided to ABC News last week by Nader's legal team.

The judge in 1991 sentenced Nader to six months in a halfway house -- well below mandatory sentencing guidelines at that time -- and allowed him to travel to both Moscow and Beirut during his criminal proceedings, later citing Nader's "extraordinary cooperation with the government in certain areas."

The 1991 criminal case was ordered sealed for six months. Instead, it remained under seal for 26 years, until a judge opened the case file last month amid news reports about Nader cooperating with Mueller. Sources told ABC News the U.S. government did not want Nader's secrets easily unearthed while he operated as a backchannel on sensitive matters.

"We used him because we needed all the channels we could get into the Syrian security establishment," said a former top career American diplomat in Damascus, who was aware of Nader's activities in the years following his 1991 conviction. "Nobody was looking for his child porn case. Nobody cared about that stuff at all back then. He was providing too invaluable a service to us."

Nader, according to one former diplomat, has a rare and valuable skill.

"His stock in trade is access and influence,” the former diplomat said. “He finds a way to be valuable to people.”

But Nader had dropped off the radar of many former associates two decades ago, including those who worked in Washington for his "Middle East Insight" magazine, which held many foreign policy discussions hosted by Nader and televised on C-Span until it folded around the time of his criminal conviction.

"Until his name appeared recently, I had no idea that Mr. Nader was even alive," said one former writer at the magazine, who, like most of Nader's associates, declined to be identified by name.