Former US president Donald Trump. Photo: AFP

Donald Trump is "guilty of numerous felony violations," said a prosecutor who resigned from a criminal probe into the former US president's business practices, according to his resignation letter published Wednesday by the New York Times. 

Mark Pomerantz, who led the New York investigation into Trump's finances, resigned on February 23 along with Carey Dunne, the other lead prosecutor on the case.  

Pomerantz's letter said that he had quit over the decision by new Manhattan district attorney Alvin Bragg not to move ahead with prosecution of the Republican billionaire. 

That decision, he wrote in the letter which the US daily published in full, was "contrary to the public interest."

"The team that has been investigating Mr Trump harbors no doubt about whether he committed crimes - he did," Pomerantz wrote. 

The investigation had probed whether Trump fraudulently overvalued multiple assets to secure loans and then undervalued them to minimize taxes. It was launched by Bragg's predecessor Cyrus Vance, with Bragg taking over the case when he took office in January.

When Dunne and Pomerantz resigned in February, Bragg's spokesperson said that the investigation was "ongoing."

The Times reported that he has told aides the case can move forward if new evidence emerges or a Trump insider decides to turn on the former president. But, Pomerantz wrote: "No events are likely to occur that will alter the nature of the case... There are always additional facts to be pursued."

But the decision not to prosecute "will doom any future prospects that Mr Trump will be prosecuted for the criminal conduct we have been investigating," he continued.

Republican Trump, 75, has not been charged and has repeatedly described the case as a political witch hunt by a Democratic prosecutor.

In July 2011, the Trump Organization and its long-serving finance chief, Allen Weisselberg, were charged with 15 felony fraud and tax evasion charges. They pleaded not guilty, and Weisselberg's trial is due to begin in the middle of 2022.

The criminal investigation into Trump is very similar to a civil inquiry being conducted by New York state Attorney General Letitia James, who is also a Democrat. In January, she said her probe had uncovered "significant evidence" of fraudulent or misleading practices at the Trump Organization.

James can sue the Trump Organization for damages over any alleged financial misconduct but cannot file criminal charges.

Trump has so far kept Americans guessing about whether he intends to seek the Republican presidential nomination again, but the host of legal probes threatens to complicate any bid for another run at the White House in 2024.

AFP