NEW YORK — Manhattan's district attorney has convened the grand jury that is expected to decide whether to indict former president Donald Trump, other executives at his company or the business itself, should prosecutors present the panel with criminal charges, according to two people familiar with the development.

The panel was convened recently and will sit three days a week for six months. It is likely to hear several matters — not just the Trump case ­— during its term, which is longer than a traditional New York state grand-jury assignment, these people said. Like others, they spoke on the condition of anonymity to discuss an ongoing investigation. Generally, special grand juries such as this are convened to participate in long-term matters rather than to hear evidence of crimes charged routinely.

The move indicates that District Attorney Cyrus R. Vance Jr.’s investigation of the former president and his business has reached an advanced stage after more than two years. It suggests, too, that Vance thinks he has found evidence of a crime — if not by Trump, by someone potentially close to him or by his company.

Vance’s investigation is expansive, according to people familiar with the probe and public disclosures made during related litigation. His investigators are scrutinizing Trump’s business practices before he was president, including whether the value of specific properties in the Trump Organization’s real estate portfolio were manipulated in a way that defrauded banks and insurance companies, and if any tax benefits were obtained illegally through unscrupulous asset valuation.

The district attorney also is examining the compensation provided to top Trump Organization executives, people familiar with the matter have said.

In a statement issued Tuesday evening, Trump called the seating of the grand jury “a continuation of the greatest Witch Hunt in American history.”

“This is purely political, and an affront to the almost 75 million voters who supported me in the Presidential Election, and it’s being driven by highly partisan Democrat prosecutors,” Trump said. “Our Country is broken, our elections are rigged, corrupt, and stolen, our prosecutors are politicized, and I will just have to keep on fighting like I have been for the last five years!”

A spokesman for Vance (D) declined to comment.

In May 2021, The Post’s David Fahrenthold told us what is known — and what isn’t — about two New York state investigations of the Trump organization. (Luis Velarde/The Washington Post)

Although grand juries with extended terms can hear cases out of order and to varying levels of completion, it is likely that Trump-related testimony in the secret proceeding has already begun, said one of the people familiar with the matter.

Adam S. Miller, who served as deputy bureau chief of the Major Economic Crimes Bureau in the Manhattan District Attorney’s Office before entering private practice in 2011, said such a “special grand jury” is “certainly not an uncommon thing to do with a large, technical and complicated investigation.”

“It’s really for very complicated cases that have a lot of information for a grand jury to digest,” Miller said, noting that a special grand jury’s term can be extended with a judge’s approval.

It is unclear whether prosecutors working under Vance intend to go through the entirety of their grand-jury presentation at once or if the proceeding may be interrupted for the panel to review other cases between hearing from witnesses about the Trump Organization and its business dealings.

It is also unclear when or even whether the grand jury will be asked to consider returning any indictments. Prosecutors handling cases such as this one can choose to present charges for the grand jury to consider — or not. A prosecutor’s grand-jury strategy is often a closely kept secret and can be subject to change.

Rebecca Roiphe, a former assistant district attorney in Manhattan who is now a professor at New York Law School, said that such investigations are always formally overseen by grand juries. In the early stages, prosecutors may use a grand jury’s power just to subpoena documents without offering charges for consideration.

Roiphe said the recent step of seating a long-term panel shows that Vance’s investigation has progressed to the point that prosecutors will visit the grand jury, present evidence and witnesses, and potentially ask that charges be considered. Prosecutors were unlikely to take that step without believing they had evidence to show there was probable cause to believe someone had committed a crime, she said.

“The prosecutors are convinced they have a case. That’s at least how I read it,” Roiphe added.

Trump is facing two investigations of his business practices in New York. Both appear to have begun with the same man: Michael Cohen, Trump’s longtime lawyer and attack dog, who turned on Trump after pleading guilty to making hush-money payoffs on Trump’s behalf and lying to Congress.

Vance’s criminal investigation began in 2018, after Cohen pleaded guilty to charges stemming from the hush-money payoffs, made in the last days of the 2016 campaign to women who said they had affairs with Trump years earlier — allegations the former president denies. Vance’s investigation soon expanded, as the district attorney sought to examine millions of pages of Trump’s tax records.

Separately, New York Attorney General Letitia James (D) began a civil investigation of the Trump Organization in 2019 prompted by Cohen’s testimony to Congress, where he said Trump had misled lenders and tax authorities with manipulated valuations of his assets. Asset values were inflated at times when the company was seeking favorable loan interest rates and were deflated to reduce tax liability, Cohen has alleged. He has been interviewed extensively by Vance’s team, which has added a decorated former federal prosecutor, Mark F. Pomerantz, to help with the Trump case.

In recent months, the two investigations have appeared to converge. Both sets of investigators have sought documents related to a Trump estate in suburban New York, according to court records and people familiar with the efforts, where the then-future president obtained a $21 million tax break by agreeing to give up development rights, and a tower in Chicago where Trump’s lenders forgave $100 million of debt.

Another sign of convergence: James’s office said last week that its long-running civil probe had also spawned a criminal investigation, now being run in coordination with Vance.

The state attorney general’s office did not explain what inspired the criminal inquiry, but veterans of the office said such shifts often are triggered by evidence that indicates a defendant intended to break the law.

Trump has attacked both investigations, pointing to comments by James during her 2018 election campaign in which she called him an “illegitimate president” and promised to investigate his family business. Trump has never been criminally charged. No former U.S. president has ever been charged with a crime.

The Washington Post previously reported that Vance’s office has been trying to pressure the Trump Organization’s chief financial officer, Allen Weisselberg, into cooperating against his boss, a person familiar with the strategy confirmed. Weisselberg is said to know the ins and outs of every business transaction at the company over the course of his decades in employment there.

A lawyer for Weisselberg declined to comment when reached Tuesday.

Fahrenthold reported from Washington. Jonathan O’Connell in Washington contributed to this report.