(NewsNation) — More than six years after Donald Trump’s lawyer paid a porn actress to allegedly keep quiet about an affair she said she had with Trump, New York prosecutors are considering whether the former president should face charges in the case.

Earlier this week, Trump was invited to testify before a Manhattan grand jury in connection with the hush money investigation, according to his lawyer. On Monday, the former president’s longtime fixer and former attorney, Michael Cohen, who ultimately made the payments in question, testified before the grand jury.

Both actions suggest an indictment may be coming. If that happens, Trump would become the first former president ever to face criminal charges.

What is the case about?

In the runup to the 2016 election, Trump’s longtime attorney Cohen paid porn actress Stormy Daniels $130,000, allegedly to keep her quiet about an affair she claimed to have had with the former president.

Trump has acknowledged that he paid Cohen a “monthly retainer” as part of an agreement to “stop the extortionist accusations made by Daniels,” and denied having an affair with her. The former president said the contract had nothing to do with campaign funds, and his company logged the reimbursements as a legal expense.

Earlier in 2016, Cohen had also arranged a $150,000 payment via the publisher of the National Enquirer to former Playboy model Karen McDougal in order to quash a story about a separate alleged affair with Trump. The former president has also denied that allegation.

Cohen pleaded guilty to violating federal campaign finance law in connection with the payments, but Trump has never faced charges. Federal prosecutors said the payments amounted to illegal, unreported assistance to Trump’s campaign. They also accused Trump’s company of inflating Cohen’s reimbursement for tax purposes.

What charges could Trump face?

Manhattan prosecutors may be considering at least two different options — both of which could be difficult to prove.

If Trump’s company had a phony retainer agreement with Cohen that Trump knew about, then prosecutors could make the case that the former president falsified business records. That crime is only a misdemeanor under New York law unless prosecutors can prove he falsified the records to conceal another crime.

That separate crime, prosecutors may argue, was a violation of state election law. Authorities could make the case that Trump paid off Daniels to benefit his campaign.

But legal experts say that could be hard to prove.

“The felony charge would be a novel one, and they’d have to show specifically that the payoff was to influence the campaign,” NewsNation’s Dan Abrams said Wednesday.

Trump’s attorney, Joe Tacopina, maintains that no crime has been committed, and said the payment was not related to Trump’s campaign.

“(Trump) would have done this if he were the TV star that he was before politics ever entered his world,” Tacopina told Abrams.

The legal case against the former president is further complicated by the fact that the prosecution’s key witness, Cohen, has previously lied to Congress.

On Friday, Cohen told “Good Morning America” that he was “absolutely” prepared for cross-examination in a potential trial against his former boss.

How likely is an indictment?

Trump was invited to testify before a New York grand jury that has been investigating the hush money payments, according to one of his attorneys. The invitation could signal that a decision on the indictment is coming.

“(An indictment) is becoming more probable, I think now,” Tacopina told Abrams.

Tacopina has said the former president has no plans to participate in the investigation.

A number of key people related to the hush money probe have already talked to authorities about the case.

Cohen testified before the grand jury investigating the payments on Monday. Two days later, Daniels met with Manhattan prosecutors and answered questions related to the investigation. Her attorney said she was willing to be a witness should the case go to trial.

Why now?

It’s not entirely clear why Manhattan prosecutors would bring criminal charges against Trump now after federal prosecutors previously declined to do so, though at that time Trump was the sitting president.

The Manhattan DA’s office opened its own investigation into the payments in 2019, revisiting it several times while looking into other matters related to Trump’s business dealings.

In December, the Trump Organization was convicted of tax fraud in a separate case unrelated to the hush money allegations. A jury found two corporate entities at the Trump Organization guilty on all 17 counts, including charges of conspiracy and falsifying business records, although Trump himself was not on trial.

Tacopina thinks charging Trump now would be a mistake.

“We’ll chew this case up,” he said. “This would be the worst stain on this DA’s legacy.”

What about Trump’s other cases?

The hush money investigation is just one of many potential criminal cases Trump faces as he mounts his third consecutive White House bid.

Prosecutors in Georgia could bring criminal charges against the former president for allegedly interfering in the 2020 election. The special grand jury in that case wrapped up its work in December and the district attorney will now decide whether to go to a regular grand jury for one or more indictments in the case.

Trump is also facing a federal investigation into the storage of classified documents at his Florida home. U.S. Attorney General Merrick Garland appointed a special counsel, Jack Smith, to oversee the probe. The Justice Department has suggested the documents were knowingly withheld after Trump left office.

Smith’s office is also looking into Trump’s attempts to overturn the 2020 election and his potential role in the Jan. 6 Capitol riot.