Donald Trump has expressed fears he could be facing arrest within days as a result of proceedings under way in New York.
A decision on whether to indict Mr Trump in connection with alleged “hush money” payments to conceal an intimate encounter with porn star Stormy Daniels is expected to be taken within days by a grand jury in the city.
Security measures have been stepped up around the courthouse in Manhattan after Mr Trump called on his supporters to “protest” against the proceedings and “take our nation back”.
What is a grand jury and how does it work?
Under New York law, a grand jury is set up by prosecutors investigating a potential crime to determine whether there is probable cause a crime has been committed, and whether there is enough evidence to pursue a prosecution.
Like a jury for a criminal trial, jurors are randomly selected from members of the public on the roll of voters – but while a criminal jury is usually comprised of 12 people, a grand jury can have up to 23.
Grand juries can review evidence, seek to investigate and call witnesses to provide testimony, with prosecutors hoping to convince members of the grand jury that there is enough evidence that a crime has occurred.
But everything that happens in the grand jury room is secret – there is no judge, and the media are not present.
The job of the jurors sitting on the grand jury is to vote on whether there is enough evidence to put someone to trial. Typically, at least 12 votes are needed to bring an indictment – a formal charge for a crime, and the beginning of the criminal trial process.
It is followed by an arraignment, when the defendant is taken to court to be told of the charges against them. At this point, they may have the chance to plead guilty or not guilty. If there is no guilty plea, a full trial will proceed at a later date.
What has happened in the Trump case?
Manhattan district attorney Alvin Bragg convened the grand jury in January to hear evidence relating to the former president’s role in hush money payments allegedly made to adult film performer Stormy Daniels.
Mr Bragg has reportedly presented evidence about a $130,000 (£106,000) payment to Ms Daniels made by Mr Trump’s lawyer, Michael Cohen, during the 2016 presidential campaign in exchange for her keeping quiet about an alleged romantic encounter.
A payment from Mr Trump’s firm to Mr Cohen was falsely recorded as for legal services, prosecutors allege.
The grand jury has heard evidence from Mr Cohen, who has supplied evidence to prosecutors after his own jailing in 2018 for tax evasion and campaign finance violations in connection with the alleged payoffs.
Testimony is also thought to have been heard from David Pecker, the former publisher of supermarket tabloid The National Enquirer, alleged to have helped the arrangement with Ms Daniels.
It is thought Mr Trump, who denies wrongdoing, declined an invitation to testify before the grand jury.
But at the request of his lawyers, on Monday the grand jury was expected to hear from Robert Costello, formerly a legal adviser to Cohen who was reportedly set to raise questions about Cohen’s credibility.
Mr Costello’s appearance comes amid speculation that the grand jury could conclude its proceedings and vote within days on an indictment.
Reports emerged at the weekend that several security agencies including the Secret Service, which is tasked with guarding former presidents, have been involved in high-level discussions relating to logistics for a potential arrest of Mr Trump if he is indicted.
On his Truth Social platform, Mr Trump reacted to the reports with anger and claimed he could be arrested on Tuesday – a detail not contained in the public reports. The New York Times, however, reports there may be a delay of several days due to the intricacies involved in negotiating the surrender to authorities.
Standard procedure would see Mr Trump read his rights before having a mugshot and fingerprints taken – though questions linger over whether the Secret Service would allow him to be handcuffed for security reasons. After the arraignment he would be released awaiting trial.
If he is charged, Mr Trump would become the first former US president to face criminal prosecution, paving the way for one of the most high-profile trials in US history to be held at a later date.
Significant reinforcements have since been put in place around the Manhattan courthouse this week amid the attention. Mr Bragg cited “public comments surrounding an ongoing investigation” for the step, adding that law enforcement would ensure the courthouse remains “a secure work environment”.
What has the response been?
Mr Trump, who plans to run for president again in 2024, has attempted to dismiss the investigation as a “corrupt and highly political” probe – attempting to impugn the record of the district attorney in the case, Mr Bragg, as a Democrat pursuing a “witch hunt” against him.
District attorneys, who serve as chief prosecutors across an area, are elected officials in nearly all US states. They have some discretion on how they would like to prosecute a case, or whether to decline to prosecute certain cases entirely.
Other leading Trump-aligned Republicans, including former vice president Mike Pence and Florida Governor Ron DeSantis have also attacked the decision to pursue possible charges. Mr Pence claimed on Sunday: “The fact that the Manhattan DA thinks that indicting President Trump is his top priority, I think is, just tells you everything you need to know about the radical left in this country.”
However, legal experts have defended the integrity of the grand jury process, and many believe it is likely that Mr Trump will be indicted.
Despite the public bluster, Mr Trump’s lawyers have quietly conceded he will follow “normal procedures” in surrendering to face criminal charges if indicted.
Mr Trump is facing several other investigations into his conduct, with a grand jury also empanelled in Georgia to investigate a call in which Mr Trump told officials to “find” votes needed to overturn his 2020 election defeat in the state.
A special counsel is also investigating classified documents found at his Mar-a-Lago residence.