A New York judge ruled on Thursday that former US president Donald Trump and two of his adult children must answer questions under oath in the state attorney general's civil investigation into their family company's business.
Justice Arthur Engoron of New York state court in Manhattan ruled in favour of Attorney General Letitia James, who sought to enforce subpoenas to compel testimony from Mr Trump, his son Donald Trump Jr and his daughter Ivanka Trump.
Mr Engoron said Ms James had “the clear right” to question the Trumps after having uncovered “copious evidence of possible financial fraud”.
He directed the Trumps to submit to questioning within 21 days.
The decision followed a two-hour hearing in which the Trumps' lawyers accused Ms James of doing an end run around their clients' constitutional rights by seeking evidence she could them use against them in a parallel criminal investigation.
Mr Trump's lawyer Alina Habba accused Ms James of “selective prosecution and prosecutorial misconduct that this country has never seen”, citing statements reflecting the Democratic attorney general's “vile disdain” for the former president.
“If he was not who he is, she would not be doing this,” Ms Habba said. “This court can help stop this circus.”
Kevin Wallace, a lawyer from Ms James's office, rejected Ms Habba's comments.
“They haven't shown anything here that says it's unfair,” Mr Wallace said.
Last month, Ms James said her nearly three-year investigation into the Trump Organisation had uncovered significant evidence of possible fraud.
She described what she called misleading statements about the values of the “Trump Brand” and six Trump properties, saying the company may have inflated real estate values to obtain bank loans and reduced them to lower tax bills.
The investigation partially overlaps a criminal investigation now led by Manhattan District Attorney Alvin Bragg in which the Trump Organisation and its long-time chief financial officer pleaded not guilty last July to tax fraud charges.
Mr Trump, who has not announced whether he will run again for president in 2024, has called Ms James's investigation a political “witch hunt” and is suing to try to stop it.
The hearing followed last week's decision by Mr Trump's long-time accounting firm Mazars USA to cut ties with him and the Trump Organisation, saying it could no longer stand behind a decade of financial statements.
Lawyers for Mr Trump have said he did not know enough to respond to allegations of inaccurate valuations, though he detailed some possible discrepancies in a five-page statement on Tuesday.
The Trumps have not been accused of criminal wrongdoing.