About that meeting in the Seychelles

An adviser to the United Arab Emirates with ties to current and former aides to President Trump is cooperating with the special counsel, Robert S. Mueller III, and gave testimony last week to a grand jury, according to two people familiar with the matter.

Mr. Mueller appears to be examining the influence of foreign money on Mr. Trump’s political activities and has asked witnesses about the possibility that the adviser, George Nader, funneled money from the Emirates to the president’s political efforts. It is illegal for foreign entities to contribute to campaigns or for Americans to knowingly accept foreign money for political races.

Mr. Nader, a Lebanese-American businessman who advises Crown Prince Mohammed bin Zayed Al-Nahyan, the effective ruler of the Emirates, also attended a January 2017 meeting in the Seychelles that Mr. Mueller’s investigators have examined. The meeting, convened by the crown prince, brought together a Russian investor close to President Vladimir V. Putin of Russia with Erik Prince, the founder of Blackwater and an informal adviser to Mr. Trump’s team during the presidential transition, according to three people familiar with the meeting.

Mr. Nader’s cooperation in the special counsel’s investigation could prompt new legal risks for the Trump administration, and Mr. Nader’s presence at the Seychelles meeting appears to connect him to the primary focus of Mr. Mueller’s investigation: examining Russian interference during the 2016 presidential campaign.

Mr. Nader represented the crown prince in the three-way conversation in the Seychelles, at a hotel overlooking in the Indian Ocean, in the days before Mr. Trump took office. At the meeting, Emirati officials believed Mr. Prince was speaking for the Trump transition team, and a Russian fund manager, Kirill Dmitriev, represented Mr. Putin, according to several people familiar with the meeting. Mr. Nader, who grew close later to several advisers in the Trump White House, had once worked as a consultant to Blackwater, a private security firm. Mr. Nader introduced his former employer to the Russian.

The significance of the meeting in the Seychelles has been a puzzle to American officials ever since intelligence agencies first picked up on it in the final days of the Obama administration, and the purpose of the discussion is in dispute. During congressional testimony in November, Mr. Prince denied representing the Trump transition team during the meeting and dismissed his encounter with Mr. Dmitriev as nothing more than a friendly conversation over a drink.

A lawyer for Mr. Nader did not respond to requests for comment. A spokesman for Mr. Dmitriev has repeatedly declined to comment about the Seychelles meeting, as has Yousef al-Otaiba, the Emirati ambassador in Washington.

Mr. Dmitriev, a former Goldman Sachs banker with an M.B.A. from Harvard, was tapped by Mr. Putin in 2011 to manage an unusual state-run investment fund. Where other such funds seek to earn returns on sovereign wealth, Mr. Dmitriev’s Russian Direct Investment Fund seeks outside investments, often from foreign governments, for unglamorous infrastructure projects inside of Russia.

The Obama administration imposed sanctions on the fund as part of a raft of economic penalties after the Russian government sent military forces into Ukraine in 2014.

The United Arab Emirates, which Washington considers one of its closest Arab allies, has invested heavily in Mr. Dmitriev’s fund as part of an effort to build close relations to Russia as well. After Crown Prince Mohammed met with Mr. Putin in 2013 in Moscow on a state visit, two investment arms of the government in Abu Dhabi committed to invest $6 billion in the Russian Direct Investment Fund, eventually paying to build projects like roads, an airport and cancer treatment centers in Russia.

Mr. Dmitriev became a frequent visitor to Abu Dhabi, and Emirati officials came to see him as a key conduit to the Russian government. In a 2015 email, the Emirati ambassador to Moscow at the time described Mr. Dmitriev as a “messenger” to get information directly to Mr. Putin. The email was among a large number hacked from the account of the ambassador to Washington and published online. The now former ambassador to Moscow, Omar Saif Ghobash, did not respond to an email about the leak.

Mr. Nader was first served with search warrants and a grand jury subpoena on Jan. 17, shortly after landing at Washington Dulles International Airport, according to two people familiar with the episode. He had intended to travel on to Mar-a-Lago, Mr. Trump’s Florida estate, to celebrate the president’s first year in office, but the F.B.I. had other plans, questioning him for more than two hours and seizing his electronics.

Since then, Mr. Nader has been questioned numerous times about meetings in New York during the transition, the Seychelles meeting and meetings in the White House with two of Mr. Trump’s senior advisers, Jared Kushner and Stephen K. Bannon, who has since left the administration.

The meeting in the Seychelles also took place against the backdrop of a larger pattern of secretive contacts between the Trump team and both the Russians and the Emiratis. In the weeks after the 2016 presidential election, Crown Prince Mohammed aroused the suspicions of American national security officials when they learned that he had breached protocol by visiting Trump Tower in Manhattan without notifying the Obama administration of his visit to the United States.