The publicist, Rob Goldstone, a former British tabloid journalist and the president of a marketing company called Oui 2 Entertainment, has worked with Emin Agalarov, and was involved with the Miss Universe pageant in Moscow. Mr. Goldstone said he helped to arrange and attended the June 9, 2016, meeting at Trump Tower with the lawyer, Natalia Veselnitskaya.
The Agalarovs, who did not respond to an email seeking comment, are originally from Azerbaijan, but now run the Crocus Group, a large real estate development company in Russia. Shortly before the Miss Universe pageant in November 2013, Mr. Putin presented Aras Agalarov with the Order of Honor, one of Russia’s highest civilian awards. Several years earlier, the Crocus Group was selected to build the Far Eastern Federal University near Vladivostok.
Mr. Trump, an owner of the Miss Universe pageant at the time, chose the Agalarovs to host the beauty competition in 2013 in Moscow, and discussed collaborating with them on a tower in Moscow. He also appeared in one of Emin Agalarov’s music videos, which featured pageant contestants.
The pageant took place at a Crocus Group complex, and it put Mr. Trump in contact with influential people in Russia, as he explained in a September 2015 interview on “The Hugh Hewitt Show.”
“I called it my weekend in Moscow,” said Mr. Trump, who had announced his candidacy for president a few months earlier. He added: “I was with the top-level people, both oligarchs and generals, and top-of-the-government people. I can’t go further than that, but I will tell you that I met the top people, and the relationship was extraordinary.”
Aras Agalarov told The Washington Post last year that Mr. Putin was planning to meet with Mr. Trump during his visit to Moscow, but had to cancel at the last minute because of a scheduling conflict. Instead, he said, the Agalarovs passed along a friendly note from Mr. Putin and a traditional Russian box as a gift.
Emin Agalarov, who is known for being accompanied by beautiful women, and was once married to the daughter of the president of Azerbaijan, has said his relationship with Mr. Trump began when he requested that Olivia Culpo, the 2012 Miss Universe, star in a music video he was making for a song called “Amor.”
In January 2013, the Agalarovs traveled to Las Vegas to meet with Mr. Trump. The Miss USA pageant was being held there, and at the end of the competition, Mr. Trump announced that the Agalarovs would host the Miss Universe competition in Moscow later that year.
While in Russia, some of the contestants were required to film scenes for the “Amor” video, among them Erin Brady, that year’s Miss USA winner. During an interview earlier this year, Ms. Brady said that the women weren’t paid for the work and that it was seen as a requirement.
The pop star made an impression.
“If you think of a traditional Russian person, they’re like serious,” Ms. Brady said. “He was laughing and much more outgoing. He made everyone feel very welcome.”
She added: “He was excited that all of these women from all over the world were part of his production.”
During his time in Moscow, Mr. Trump also found time to film a scene for the video.
There also was discussion of development deals — and introductions to other well-connected Russians.
During the visit, the Agalarovs and Herman Gref — a former Russian economy minister who serves as the chief executive of the state-controlled Sberbank PJSC — hosted a dinner for Mr. Trump on the night of the pageant, according to Bloomberg News.
Phil Ruffin, Mr. Trump’s partner at the Trump International Hotel and Tower in Las Vegas, who flew to Moscow for the competition, said he and Mr. Trump had lunch with the Agalarovs at the Ritz-Carlton.
Hope for a deal with the Agalarovs came after many failed attempts by the Trumps to break into the real estate market in Russia dating back to the late 1980s.
Donald Trump Jr., speaking at a Manhattan real estate conference in 2008, told the audience he had been to Russia a half-dozen times over an 18-month period. “I really prefer Moscow over all cities in the world,” he said, according to eTurboNews. But he acknowledged that the Russian market was challenging, with “an issue of ‘Will I ever see my money back out of that deal or can I actually trust the person I am doing the deal with?’ ”
But after the Miss Universe weekend, his father sounded optimistic and grateful to the Agalarovs.
“I had a great weekend with you and your family,” Mr. Trump wrote on Twitter. “You have done a FANTASTIC job. TRUMP TOWER-MOSCOW is next. EMIN was WOW!”
Emin Agalarov told Forbes in March that plans for the joint project came to an end when Mr. Trump ran for office, but that the president has maintained contact with the family. He added that President Trump sent the Agalarovs a handwritten note after his election win.
“Now that he ran and was elected, he does not forget his friends,” he told the magazine.
Emin Agalarov also said he exchanged messages with Donald Trump Jr. as recently as January.
After Mr. Trump’s victory in November, Emin Agalarov posted a photo of himself, his father, and Mr. Trump on Instagram with the message, “The sky is the limit! Congratulations Mr. President.”
The Miss Universe pageant has been the subject of particular intrigue for months, given the federal investigation into the Kremlin’s meddling in the presidential election, and the question of whether the Trump campaign colluded with Russian officials — a claim that the president and his associates have denied.
Donald Trump Jr. said in a statement on Sunday that Ms. Veselnitskaya, the Russian lawyer, did not provide any information of value about Mrs. Clinton, his father’s opponent in last year’s election, during the June 2016 meeting. He said the conversation soon turned to the adoption of Russian children, and an American law called the Magnitsky Act, which blacklists those suspected of human rights abuses in Russia.
“Obviously I’m the first person on a campaign to ever take a meeting to hear info about an opponent… went nowhere but had to listen,” he said Monday on Twitter.