When the Trump Organization left the Dominican Republic after the economy crashed ten years ago, their plans for dozens of luxury estates in a Trump-branded development appeared to leave with them. Buyers who staked millions on lots for their dream homes were left empty handed. The Trump team sued the developers, alleging fraud. And the billboards bearing the Trump name came down.

Now, there are signs the Trump brand may be returning to the Dominican Republic, and that has critics sounding alarms about the potential conflicts of interest for the sitting president of the United States.

“The constitution is very clear,” Sen. Ben Cardin, a Democrat from Maryland on the foreign relations committee, told ABC News. “We expect the President to avoid these types of conflicts.”

The first sign the Trumps might try again came 16 days after Donald Trump took the oath of office. His son Eric made a visit to the island on Feb. 5. 2017 to meet with the same developers he had once accused of “textbook fraud.” With the legal case settled, they had appeared to make peace.

“We are excited to be working with the Trump Organization in the future phases of the project,” a press release from the local developers said at the time. The visit sparked months of rumors, but no details emerged about how or when the Trump Organization would make its formal return to the island, and the original property where Trump helped market luxury estates remained largely barren.

But last month, the non-profit group Global Witness sent an undercover investigator to see if they could learn more. The group, which has a 25-year history of investigating corrupt regimes, human rights abuses, and money laundering, shared their findings exclusively with ABC News. That included undercover recordings that captured a sales agent at the Cap Cana resort describing a Trump-branded condominium development in the works for a new, beachfront location.

“We’re going to have a new development with the Trump Organization of apartments and commercial areas,” a saleswoman told a man she thought was a potential buyer who was actually a Global Witness investigator. “That is still in the works … With the Trump Organization, everything right now is on good terms.”

The saleswoman showed the investigator the beachfront location on a map of the sprawling Cap Cana resort community where she believed a Trump-branded project was slated to be built, and a man identifying himself as her boss confirmed it was in the works – a new phase of the original deal between the Trumps and local developers.

The Trump Organization calls the Global Witness report “completely false,” maintaining that it has no new development deals in the works and insists talks with the Dominican developers have been infrequent. “In 2007, the company entered into a license agreement with a local developer for a multi-component real estate development project to be built over several years,” said the company in a statement. “Though there have been some discussions about starting the next phase of the development, there are no plans in place at this time.”

An executive at the Trump Organization told ABC News that the company’s original 2007 agreement always envisioned their return to build a beachfront hotel and condominium project. “This was all contemplated from day one,” said the executive, who asked to remain anonymous because he was not authorized to discuss the deal publicly.

The potential for conflicts of interest is a unique issue that confronted Trump even before he took office, as the first president in years who came into office with vast global business empire – with many deals still in the works -- and without any agreement to place that business into a blind trust. His business is run by his adult children, but their successes and failures still have the potential to impact his personal wealth.

Global Witness and other critics say any move by the Trump Organization to return to the island nation could represent a departure from the president’s promise to avoid undertaking fresh overseas developments during his term in office. It was a promise made nine days before Trump took the oath of office.

He told a gathering of reporters “I won’t have any conflicts of interest” before ceding the stage to his attorney, Sheri Dillon, who said Trump would insist on written approval from an ethics adviser “for new deals, actions, and transactions that could potentially raise ethics or conflicts of interest concerns.”

“President-elect Trump as well as Don [Trump Jr.], Eric [Trump]and [the company’s chief financial officer] Allen [Weisselberg] are committed to ensuring that the activities of the Trump organization are beyond reproach and cannot be perceived to be exploitive of the office of the presidency,” she said, adding: “No new foreign deals will be made whatsoever during the duration of President Trump’s Presidency.”

A Trump Organization official did not respond when asked if the firm had received any ethics guidance about renewed discussions about the Dominican development. Neither the Cap Cana developer, nor a New York lawyer who represented them in past matters, responded to calls and emails from ABC News seeking comment.

According to investigators at Global Witness who said they have examined permitting and other records, ethics issues are present whether or not their return to the Dominican was pre-ordained by their 2007 agreement.

“New or old, Trump’s business in the Dominican Republic poses a conflict of interest for him and for the American people,” a new report from Global Witness said, “as his business interests and the foreign policy interests of the U.S. may not always align.”

Cardin said the conflicts run both ways. “If a foreign country wants to do a favor for the President by helping his business interests, they are expecting that will help them get favors here from the United States,” he said. At the same time, “it raises questions to everyone on whether decisions made by the President of the United States are based on what's in the best interest of the United States or the best interest of his business."

There have been signs the Dominican Republic has sought to influence the Trump Administration in a range of areas. Just weeks after the inauguration and Eric Trump’s visit to the Dominican Republic, the Dominican government hired a Washington, D.C. lobbying firm for the first time since 2007.

According to Justice Department filings reviewed by ABC News, the office of the Dominican president signed a $1.2 million contract with lobbyist Brian Ballard, who had previously represented Trump, and has been described in Politico as “closer to the president than perhaps any other lobbyist in town.” The lobbyist pledged to “advise, counsel, and assist,” the Dominican president “in communications with U.S. government officials.”

Other filings through the Foreign Agent Registration Act show Ballard’s office sharing updates with U.S. officials on a range issues with the U.S., including trade, alternative energy, as well as the country’s continued importance as a vacation destination for American tourists.

Ballard did not respond to questions from ABC News.

Eryn Schornick, an attorney with Global Witness, said she is concerned that the president may have a personal motivation to help the Dominican Republic with whatever dealings are going on between the two countries.

“He may be acting in his own accord and not on the interests of American people,” she said.

Right now, no federal ethics laws prevent the president from operating his business as he sees fit, but Cardin said he would like to see Congress take additional steps to address the potential for conflicts.

“That conflict is there,” Cardin said. “As we see in the Dominican Republic, they are doing additional business. So they have not even drawn the line at their current business enterprises. They are expanding them.”

Already, Democrats in Congress have indicated they plan to closely examine the president’s foreign dealings when they take control of the House of Representatives next month.

ABC News' Cho Park and Aicha El Hammar contributed to this report.

This report was featured in the Dec. 18, 2018, episode of ABC News' daily news podcast "Start Here."

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