A prominent outside super PAC supporting President Biden's candidacy paid tens of thousands to a Biden family friend who previously registered as a foreign agent and discussed business opportunities with the president's son, Hunter, filings reviewed by Fox News Digital show. 

Unite the Country disbursed nearly $54,000 to Prairie Avenue Advisors LLC for fundraising consulting so far this year, according to the committee's mid-year report released Friday. Prairie Avenue Advisors is a Chicago-based company registered to Mark Doyle, who served as a senior Biden adviser in the Senate and later as the national finance director for Biden's failed 2008 presidential campaign. 

Since Unite the Country's launch in 2019, Doyle, who acts as its chairman, has pocketed over $500,000 from the committee. The group spent significant amounts backing Biden's 2020 candidacy and appears to be gearing up to do so again in 2024. 

The close Biden confidante also previously discussed foreign business prospects with the president's son.

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Fox News Digital previously reported on multiple exchanged emails between Doyle, who was registered as a foreign agent on behalf of the Republic of Serbia at the time, and Hunter Biden early in his dad's first term as vice president during the Obama administration. They plotted a potential business meeting with then-Serbian President Boris Tadic and Serbian "high net worth individuals." 

According to a disclosure filed with the Department of Justice, Doyle was registered as a foreign agent through the same Chicago-based firm that Unite the Country pays, and he principally dealt with Serbian Ambassador to the United States Vladimir Petrovic, who Hunter Biden met for the first time in February 2010 alongside Tadic's National Security Advisor Jovan Ratkovic.

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"I met with Tadic's Chief of Staff Thursday[sic] when I was there and he asked about you. The Ambassador must have relayed your conversation," Doyle wrote in an April 2010 email, referring to Petrovic.

"I think you mentioned that you spoke to them about putting you in front of high net worth individuals and they are ready to do that, and to have you meet Tadic as well. I am going there with Milan in May, and I think they are looking for you to join," Doyle continued. "My sense from Vladimir is that they are very willing to help you with your fund. If you have interest you can just call Vladimir direct, you don't need me in the middle. I think it could be good for you and the fund to go."

Hunter Biden responded a few hours later, joking that "Markie in the Middle" would be the name of the "reality show" he will be producing and expressed interest in the meeting.

"How about we go over around May 10th. JRB will be in Madrid and I can catch a ride with him and fly over to Serbia and back with you," Hunter wrote, referring to his father by his initials.

Doyle followed up a few days later, alerting Hunter that Petrovic, who was serving as the Serbian Ambassador to the United States at the time, "wants to start putting together a full day for you with Tadic and potential investors."

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"They are ready to get people who can commit immediately when you are there, very serious people from what I understand," Doyle added.

Other emails that followed included messages from Hunter Biden's longtime business partner, Eric Schwerin, who visited the White House at least 27 times during the Obama administration, and Petrovic.

Schwerin emailed Hunter and Doyle about a week later about the Serbia trip and said, "Hunter would like to try and get to Serbia right after going to Madrid with his Dad."

"The Madrid trip should end on Sunday the 9th so he could likely get to Belgrade Sunday night and stay the 10th and 11th (not sure how much time he needs and if he could depart on the afternoon of the 11th or would depart afternoon of the 12th)," Schwerin added.

Hunter responded three days later, in late April 2010, saying there was a "change in the schedule" to his travels in Europe that week, and he didn't think he could make the trip on the week of May 11 but noted that he would like to visit another time during the spring.

Petrovic followed up a week later apologizing for his late response and informed Hunter that he had some "preliminary conversations with some business people in Serbia" and that he thought Hunter "would find some opportunities" when he visited in the future.

Based on previous Fox News Digital reporting, it is unclear whether Hunter or Schwerin ended up visiting Serbia or taking Petrovic up on his offer to meet with wealthy business individuals in Serbia. However, emails show that Hunter, Schwerin and Petrovic continued to communicate after Petrovic became a D.C. lobbyist after leaving the ambassadorship.

Unite the Country did not immediately respond to a Fox News Digital request for comment.