New York, New York - Donald Trump refused to answer questions from the New York attorney general’s office Wednesday in the latest twist in an ongoing civil investigation into his real estate business.

"Under the advice of my counsel... I declined to answer the questions under the rights and privileges afforded to every citizen under the United States Constitution," the former president said, pleading the Fifth.

"This is a vindictive and self-serving expedition, the likes of which this country has never seen before," he continued. "The United States Constitution exists for this very purpose, and I will use it to the fullest to defend myself against this malicious attack."

Trump's children Ivanka and Donald Jr. will also have to sit for questioning as part of New York Attorney General Letitia James’ probe of the Trump Organization, after an appeal against an order by Manhattan Supreme Court Justice Arthur Engoron failed in May.

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"Seeing racist NYS Attorney General tomorrow, for a continuation of the greatest Witch Hunt in US history!" Trump raved Tuesday on his Truth Social account. "My great company, and myself, are being attacked from all sides. Banana Republic!"

The 76-year-old was seen leaving Trump Tower in Midtown about 8:30 AM, according to a New York Times’ live blog. He waved to a few onlookers, some chanting loudly "Lock him up!" before getting in a black SUV.

A half-hour later, his motorcade arrived in downtown Manhattan at the Liberty St. office of the New York attorney general. Secret Service agents and NYPD officers were stationed outside the attorney general’s office as Trump rolled into a parking garage.

Trump’s deposition comes two days after the FBI executed a search warrant at his Mar-a-Lago home in Florida as part of a probe into the handling of presidential and classified documents that may have been taken from the White House.

The former commander-in-chief, who was in New York when the raid took place, confirmed that FBI agents searched the sprawling beachfront compound and complained that they "broke into my safe." He's now using the incident to fundraise.

James, meanwhile, is investigating whether Trump and his kids violated the law through serial manipulation of the values of his properties to obtain loans, tax breaks and other benefits.