Nine days after Donald Trump announced he was about to be arrested over a hush-money payment to a porn star, the world still awaits what would be one of the most famous police mugshots in history.

The Republican former US president, who has never been shy about grabbing the limelight, sent newsrooms in the United States and beyond into a spin on March 18 when he announced he was three days away from being brought before a New York judge.

Trump, it turned out, had bad information or was simply guessing, and his equally baseless claim a week later that the case had been dropped altogether was greeted with due incredulity.

The prosecutors may not be marching to Trump's tune but legal analysts genuinely expect the 76-year-old -- who is running again for the White House -- to be read his Miranda rights any day now.

A grand jury -- a panel of citizens with broad investigative powers that works with prosecutors -- reconvened Monday in Manhattan, where they reportedly heard from the former publisher of the National Enquirer, a central player in the hush money payment scheme.

The probe centers on $130,000 paid weeks before the 2016 election to adult film star Stormy Daniels to stop her from going public about a sexual encounter she says she had with Trump a decade earlier.

Trump's ex-lawyer Michael Cohen, who has testified before the grand jury, told Congress in 2019 that he made the payment on Trump's behalf and was later reimbursed.

Prosecutors say the checks were not properly registered, which might normally result in a misdemeanor charge of falsifying business records.

But that could be upgraded to a felony if the district attorney can persuade the grand jury that the payment and the suspect accounting were part of a cover-up, intended to benefit Trump's election campaign by burying the scandal.

There are strict laws about how much candidates can contribute to their own election bid, and secretly funneling money toward campaign coffers can lead to jail terms of several years.

Criminal charges of any level would be uncharted territory in the United States, which has never indicted a sitting or former president.

If the jury votes to indict Trump, Manhattan's chief local prosecutor is obliged to comply with their decision and announce it to the public.

Accused by Trump and the former president's allies in the House of Representatives of a political "witch hunt," prosecutor Alvin Bragg, an elected Democrat, has hit back at Republican "interference" in the investigation.

In an interview that aired Monday night with Fox News, Trump said the proceedings against him amount to election interference as he makes another shot for the White House.

"In my opinion, it is a way of cheating," Trump said. "It's election interference."

"We are dealing with dishonest people and thugs and dealing with people, I believe, that hate our country," he added.

Trump staged his first official campaign rally in Texas on Saturday, brushing off his potential indictment -- denying the tryst with Daniels as he railed against multiple criminal probes threatening his 2024 bid for the White House.

"I think they've already dropped the case," Trump told reporters aboard his plane home to Florida, according to political website Axios.

"It's a fake case. Some fake cases, they have absolutely nothing."