A Manhattan grand jury is hearing evidence about whether Donald Trump illegally falsified business records in connection with a hush-money payment his lawyer made to an adult-film actress during his 2016 presidential campaign.

The grand jury could vote at any time on whether to charge Trump with a crime. He would be the first former president indicted in U.S. history.

The grand jury process is secret, so there is no way to know if Trump was right when he told his social media followers that he expects to be charged with a crime. But here's what would happen if Trump is indicted, how law enforcement is preparing for potential unrest, the next steps in the case - and more.

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Why did Trump claim he would be arrested?

For days, Trump advisers and lawyers have expected that he will be indicted in the New York case.

And on Saturday morning, Trump posted on his social media platform that he "WILL BE ARRESTED ON TUESDAY OF NEXT WEEK. PROTEST, TAKE OUR NATION BACK!"

But advisers to Trump said in the wake of his social media posting that they have not received a "notification" about an indictment. They said the former president predicted the timing of a potential indictment based on media reports that law enforcement officials were expected to convene to discuss security and logistics that may be necessary if he is charged.

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Will Trump be arrested? Is that different than being indicted?

When someone is indicted by a grand jury, it means they are charged with a crime. "An indictment is just a fancy way of saying 'the charging document,'" said Anna G. Cominsky, a professor at New York Law School. "It is a piece of paper that contains the charges."

After people are indicted, they may be placed in handcuffs and arrested - or they can voluntarily turn themselves in and avoid being taken into custody in public.

Cominsky said it seems unlikely that Trump would be publicly arrested since his attorneys appear to be in communication with prosecutors and could arrange for him to surrender.

Should he refuse to surrender, prosecutors would need to go to officials in Florida, where Trump resides, and ask for permission to extradite him to New York.

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What would happen once Trump was in custody?

Once a suspect who has been indicted is in police custody, police or other law enforcement process them behind closed doors, taking mug shots and fingerprints.

The process is identical whether the person has been arrested or has agreed - or negotiated through lawyers - to turn themselves in.

"What happens behind closed doors would still be the same," Cominsky said. "He would still be fingerprinted, he would still have his photos taken, he would still be processed, but there wouldn't be people coming to Mar-a-Lago and putting him in handcuffs if he voluntarily surrenders."

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After an indictment and surrender, what are the next steps?

The first proceeding after a potential Trump indictment and surrender (or, far less likely, an arrest) would be an arraignment hearing in a Manhattan courtroom. That is likely the latest point at which the charges and evidence against the former president would be made public, although it is possible they would be revealed earlier.

At the arraignment, a judge would determine whether Trump would need to pay bail or adhere to certain restrictions pending a trial - or whether he could be released with no bail or restrictions, which is known as being released on personal recognizance.

The judge would also set the next court date, which is the first step toward pretrial hearings, possible plea negotiations or an eventual trial.

Generally speaking, bail is reserved only for people considered to be a flight risk or accused of a significant violent crime.

"In this case, it would be extremely unlikely for there to be anything but release on his own recognizance," Cominsky said.

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What are Republicans saying about Trump's call to protests?

Republicans have attacked Manhattan District Attorney Alvin Bragg's prosecution but still have largely attempted to discourage people from heeding Trump's calls to protest.

House Speaker Kevin McCarthy, R-Calif., said at a news conference Sunday that Trump supporters should not protest if the former president is indicted.

Ali Alexander - who helped organize the "Stop the Steal" movement, which claimed the 2020 election was fraudulently stolen from Trump - tweeted that his group would not be protesting Trump's possible indictment, warning that protesters would be "jailed or worse" if they rally in New York City.

But there were some small, scattered protests in Manhattan and elsewhere early this week.

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Why are New York police beefing up security?

Law enforcement officials across the country have said they are preparing for possible unrest if Trump is indicted. In places including Atlanta and Palm Beach, Fla., authorities reviewed their options to contain demonstrations and keep participants from causing injury or destroying property.

In New York, law enforcement and court officials have sought to plot out security measures and logistics for the possible unprecedented event of a former president's first court appearance on criminal charges. As of Monday, signs of preparation were already visible outside the building as metal barricades were seen being unloaded and erected nearby.