President Donald Trump's two eldest children emerged as possible targets of special prosecutor Robert Mueller's probe of his links to Russian money laundering, based on a new report on the family's real estate business.

Trump biographer Tim O'Brien published a detailed report Wednesday on Bloomberg examining the president's ties to suspected money launderers through the Bayrock Group -- often through real estate deals negotiated by his children.

Ivanka Trump and Donald Trump Jr. come up several times in the piece, particularly in relationship with former Bayrock employee Felix Sater, a mob informant and felon who claims ties to Russian intelligence.

Bayrock partnered with Trump and his two eldest children on a series of real estate transactions between 2002 and 2011, according to Bloomberg, including the troubled Trump Soho hotel and condominium.

The Russian-born Sater and another Bayrock employee, Jody Kriss, conducted business with the Trump family on behalf of investor Tevfik Arif, a Kazakhstan native and former Soviet official living in Turkey who seeded the real estate company with a $10 million investment.

Kriss said he met most frequently with Ivanka and Donald Jr., while Sater had access to their father, but Arif was largely sidelined due to his difficulties speaking English.

He said the Trump children were involved in negotiations with Bayrock on those real estate deals, but their father had the final say.

“Donald was always in charge,” Kriss told Bloomberg. “Donald had to agree to every term of every deal and had to sign off on everything. Nothing happened unless he said it was okay to do it. Even if Donald Jr., shook your hand on a deal, he came back downstairs to renegotiate if his father told him to.”

Kriss eventually left Bayrock after coming to suspect the company was a front for a money laundering operation -- which Sater was accused of doing for the Mafia from the penthouse at 40 Wall Street, a Trump-owned building in Manhattan.

He has sued Bayrock, alleging money laundering and theft that he claims cheated him out of millions of dollars.

Sater and other Bayrock officials have described Kriss as a disgruntled employee, but a judge allowed the 9-year-old lawsuit against them to proceed as a racketeering case.

Attorneys for Kriss asked a federal judge Monday to unseal Sater's fraud conviction and other criminal records, because they said the court documents could show possible criminal activity by the president.

"A fellow named Donald Trump is now president, and he had a business associate named [Sater]," attorney Richard Lerner said Monday in a Brooklyn courtroom. "The public needs to know the length of their relationship and the nature of the relationship and what kind of person [Sater] is,. By allowing this regime of secrecy to continue, it’s facilitating what may have been fraud by President Trump."

Lerner told Newsweek that Trump may have committed financial fraud if he knowingly conducted real estate deals with a convicted felon, which Sater apparently was when he began working with the future president.

Based on Bloomberg's reporting, Ivanka and Donald Trump Jr. could potentially face the same legal jeopardy if they conducted business with Sater.

Sater served a year in prison in 1993 for stabbing a man in face with a margarita glass stem, and he fled to Moscow to avoid charges in connection with a $40 million Mafia stock fraud scheme -- although he eventually returned to the U.S. and pleaded guilty in 1998.

He avoided prison by acting as a confidential informant in the investigation of black market Stinger missiles for sale in Afghanistan, and the his racketeering case was sealed.

Sater arranged real estate deals for the Trump Organization starting in 2003, when he was still working as an informant, according to reports.

Trump cut ties with Sater in 2007, when his criminal past became public, although the resumed working together about three years later, according to the Associated Press.

The president has said over the years that he barely knows Sater, but former Bayrock employees told Bloomberg the pair met frequently at the Trump Organization headquarters, and Sater reportedly carried Trump Organization business cards.

Sater also showed Trump's children around Moscow to scout property to build a Trump-branded hotel, as part of a Bayrock pitch developed with Arif on an international chain of mixed-use properties bearing his name.

Those hotel and condominium properties are now part of a lawsuit filed by Democratic lawmakers against the president, who they argued had violated the Constitution's emoluments clause by accepting foreign payments related to those businesses.

Sater reportedly threatened to file a countersuit against Arif, who is suing his former employee over $3.5 million in legal fees, that would expose the real estate developer's alleged wrongdoing in Kazakhstan -- which came with an implied blackmail threat against the president.

“The headline will be, ‘The Kazakh Gangster and President Trump,’” Sater warned.

In the correspondence reviewed by the Journal, Sater warned he might file another lawsuit in which he would allege wrongdoing in Arif’s dealings in the post-Soviet metals business in Kazakhstan. “The headline will be, ‘The Kazakh Gangster and President Trump,’” Sater warned.

Trump's financial activities before and after becoming president also are the target of a congressional investigation and a criminal probe overseen by special counsel Mueller, who is assembling a team of prosecutors with experience investigating financial crimes.