New York, New York - Donald Trump and two of his children will have to testify in New York Attorney General Letitia James’ civil investigation into the former president’s family real estate business, an appeals court ruled Thursday.

Ivanka Trump, Donald Trump Jr., and their father had fought a February order by Manhattan Supreme Court Justice Arthur Engoron that required them to sit for questioning under oath as part of James’ probe of the Trump Organization.

They had argued that James’ investigation was an improper fishing expedition and that she was unfairly in cahoots with Manhattan District Attorney Alvin Bragg, who is conducting a parallel criminal investigation into the Trump Organization’s business practices.

The Appellate Division First Department didn't see it that way, writing in a three-page order that James had good reason to open the probe.

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Engoron had ruled it would be "a blatant dereliction of duty" for James not to question the family as she investigated whether the Trumps violated the law through alleged serial manipulation of Trump Organization property values to score favorable loans and tax breaks.

Eric Trump, the only member of the Trump to have been questioned under oath by James’ team, invoked his Fifth Amendment right against self-incrimination around 500 times.

The development is the latest blow for Trump in the probe. Engoron recently held him in civil contempt for blowing deadlines in the AG investigation and ordered he pay James $110,000 in fines.

Futerfas said the decision was under review. The Trump family can pursue an appeal to the state’s highest court.