Donald Trump's former fixer Michael Cohen testified before a grand jury in New York Monday as prosecutors near a momentous decision on whether to charge the ex-president over hush money paid to a porn star.

If Manhattan District Attorney Alvin Bragg files an indictment against the 76-year-old Trump then it would mark the first time a former US leader has been charged with a crime.

It would send shockwaves through the United States and upend Trump's bid to win the Republican nomination for the 2024 presidential election.

"My goal is to tell the truth," Cohen told reporters as he arrived at a courthouse, adding that Trump "needs to pay for his dirty deeds."

Cohen's lawyer confirmed to AFP that his questioning of his client started at 2:00 pm (1800 GMT). A spokeswoman for Bragg declined to comment.

In America, prosecutors can put witnesses and evidence in front of a citizens' panel known as a grand jury, which then decides whether there is a case to answer.

Experts say charges against Trump are likely but come with a legal risk for Bragg -- an elected Democrat -- as he reportedly pursues an untested combination of laws.

His investigation centers on a $130,000 payment made two weeks before the 2016 presidential election, which Trump won, to an adult film actress known as Stormy Daniels.

The money was allegedly intended to stop Daniels, whose real name is Stephanie Clifford, from publicly disclosing an affair she says she had with Trump years earlier.

The payment was made by Cohen, Trump's former lawyer, who said he was later reimbursed.

"He's the key witness. He'll put all the things together in terms of how the deal was made," said former prosecutor Bennett Gershman, who is following the case closely.

Cohen's appearance comes after The New York Times and Washington Post reported last week that Bragg's team had offered Trump an opportunity to testify.

Trump is almost certain to decline, to avoid potentially incriminating himself, but experts say the invitation is a sign that he will almost certainly be charged.

"I think it's pretty clear he's going to be indicted because prosecutors almost never invite the target of the investigation to testify in the grand jury unless they're planning on indicting that individual," Pace University law professor Gershman told AFP.

- 2020 probe -


The payment to Cohen, if not properly accounted, could result in a misdemeanor charge related to falsifying of business records. That might be raised to a felony if the false accounting was intended to cover up a second crime, such as a campaign finance violation, the Times has reported.

Combining the two laws in one case has never been tried before, according to the Times, and presents a gamble for Bragg. Securing a conviction would likely be difficult.

"People seem to think it's just a slam dunk. There's no such thing," Hofstra law professor Ellen Yaroshefsky told AFP.

Trump's lawyers are likely meeting with prosecutors to try to persuade them not to bring charges, experts say.

They are expected to attack the credibility of Cohen, who was sentenced to three years in prison in 2018 on federal charges related to the hush payment.

Cohen pleaded guilty but said he had been carrying out Trump's orders.

Trump denies the affair and last week lashed out on his Truth Social page, calling the investigation "a political Witch-Hunt, trying to take down the leading candidate, by far, in the Republican Party."

He is facing several criminal probes at the state and federal level over possible wrongdoing before, during and after his first term in office that threaten his new run at the White House.

In Georgia, a prosecutor is investigating Trump and his allies' efforts to overturn his 2020 election loss in the southern state. The grand jury in that case has recommended multiple indictments, the forewoman revealed last month.

The former president is also the subject of a federal probe into his handling of classified documents as well as his possible involvement in the January 6, 2021, assault on the US Capitol.