A yearslong probe into a hush money scheme involving former President Donald Trump and adult film star Stormy Daniels has led to him being indicted by a Manhattan grand jury for his alleged role in the scheme.

The indictment is historic, marking the first time a former US president and major presidential candidate has ever been criminally charged.

Here’s what to know about the hush money investigation:

What happens next: A spokesperson for Manhattan District Attorney Alvin Bragg released a statement Thursday saying the office has contacted Trump’s attorney to “coordinate his surrender” for arraignment on “a Supreme Court indictment, which remains under seal.”

“Guidance will be provided when the arraignment date is selected,” it added. Trump is expected to appear in court Tuesday for his arraignment, multiple sources tell CNN. Judge Juan Merchan is expected to preside, one source said. 

How we got here: The Manhattan DA’s investigation first began under Bragg’s predecessor, Cy Vance, when Trump was still in the White House. It relates to a $130,000 payment made by Trump’s then-personal attorney Michael Cohen to Daniels in late October 2016, days before the 2016 presidential election, to silence her from going public about an alleged affair with Trump a decade earlier. Trump has denied the affair.

At issue in the investigation is the payment made to Daniels and the Trump Organization’s reimbursement to Cohen.

According to court filings in Cohen’s own federal prosecution, Trump Org. executives authorized payments to him totaling $420,000 to cover his original $130,000 payment and tax liabilities and reward him with a bonus.

The Manhattan DA’s investigation has hung over Trump since his presidency and is just one of several probes the former president is facing as he makes his third bid for the White House.

A rare case: The grand jury’s decision marks a rare moment in history: Trump is the first former US president ever indicted and also the first major presidential candidate under indictment seeking office. The former president has said he “wouldn’t even think about leaving” the 2024 race if charged.

The decision to bring charges is not without risk nor does it guarantee a conviction. Trump’s lawyers could challenge whether campaign finance laws would apply as a crime to make the case a felony, for instance.

Cohen’s role: Cohen, Trump’s onetime fixer, played a central role in the hush money episode and is involved in the investigation.

He admitted to paying $130,000 to Daniels to stop her from going public about the alleged affair with Trump just before the 2016 election. He also helped arrange a $150,000 payment from the publisher of the National Enquirer to Karen McDougal to kill her story claiming a 10-month affair with Trump. Trump also denies an affair with McDougal.

Cohen, who was sentenced to three years in jail, met with the Manhattan district attorney’s office earlier this month and praised Bragg for offering Trump the opportunity to testify.

What Daniels has said: For her part, Daniels, also known as Stephanie Clifford, met in March with prosecutors from the Manhattan district attorney’s office probing the payment, according to a tweet sent by her attorney, who said Daniels had “responded to questions and has agreed to make herself available as a witness, or for further inquiry if needed.” 

She wrote a tell-all book in 2018 that described the alleged affair in graphic detail, with her then-attorney saying that the book was intended to prove her story about having sex with Trump is true.

Read more about the investigation here.