Special Counsel Robert Mueller has launched a new probe into President Donald Trump’s children, Ivanka Trump and Donald Trump Jr., looking into their roles in an abandoned plan to build a Trump Tower in Moscow, according to sources contributing to a Yahoo News investigation.

The Thursday report revealed that the special counsel was looking into Donald Jr.’s and Ivanka’s efforts to build a Trump Tower Moscow.

Those efforts reportedly ended in 2013, and Trump’s eldest son and daughter did not look “at any other deals after that,” the sources told Yahoo News.

Mueller was tipped off on the investigation by former Trump lawyer Michael Cohen. The former Trump fixer pleaded guilty to lying to Congress by telling officials that the Trump Organization had ceased efforts to construct a Trump-brand skyscraper in Moscow even though he continued pursuing the project until January 2016.

The special counsel claimed Cohen did so in an effort to “minimize” any links between Trump and Russia and to “give the false impression” that the possible business relationship between the two entities had ended prior to the 2016 Republican primaries.

Mueller also claimed that Cohen had lied about briefing Trump family members at the Trump Organization about the Moscow project.

Reports indicate that the efforts of Trump’s scions, who were high ranking executives at Trump’s billion-dollar real estate organization, were separate from Cohen’s.

“Michael was looking at that deal,” the source told Yahoo. “Don and Ivanka knew about it and Don testified to the Senate Judiciary Committee that he was peripherally aware of it.”

“That’s why we’re so perplexed Cohen would lie about briefing them because no one’s ever disputed that they knew he was looking at it,” the source added.

Mueller has focused greatly on the president’s business ties to Russia as part of his investigation. Any contracts Trump had with the Eastern European superpower could unearth possible conflicts of interest that could influence the president’s foreign policy decisions.