March 8, 2013  -- Sulaiman Abu Ghaith, Osama bin Laden's son-in-law and a longtime member of al Qaeda's inner circle, pleaded not guilty to the charge of conspiring to kill Americans when he appeared today in a New York federal court house less than a mile from the site of the Sept. 11, 2001 terror attacks on the World Trade Center towers.

Ghaith stood before a federal judge in a blue smock with his hands cuffed behind his back. Prosecutors said much of their case is made up of a 22-page statement that Ghaith provided upon his arrest, along with previously recorded video and audio statements.

Thursday American officials said Ghaith had already given interrogators "key intelligence" on al Qaeda's status, personnel and finances.

"It is huge," Rep. Michael McCaul (R-Texas), the chairman of the House Homeland Security Committee, said Thursday. "This is a man who is in the inner circle of bin Laden's al Qaeda operations and now we have him alive and he's talking."

READ: Arrest of Bin Laden Son-In-Law Reignites GTMO Debate

Lawmakers and U.S. officials on Thursday revealed Ghaith's capture and secret transfer to New York. After living in Iran, Abu Ghaith was taken into custody in Turkey in January and later turned over to Jordianian authorities. From there U.S. officials took over the case on Feb. 28 and spirited Abu Ghaith to New York City March 1.

Law enforcement sources told ABC News that American officials are still vetting the new intelligence from Abu Ghaith, but much of what the U.S. government is interested in involves his time spent under so-called house arrest in Iran. The sources said Abu Ghaith likely also has information on what bin Laden and other al Qaeda members were up to in the days after 9/11 but may not have been informed of any imminent plots.

DOCUMENT: Indictment Against Sulaiman Abu Ghaith

The FBI's George Venizelos referred to Abu Ghaith as holding a "key position in al Qaeda, comparable to the consigliere in a mob family or propaganda minister in a totalitarian regime."

"No amount of distance or time will weaken our resolve to bring America's enemies to justice," Attorney General Eric Holder said Thursday. "…[T]his arrest sends an unmistakable message: There is no corner of the world where you can escape from justice because we will do everything in our power to hold you accountable to the fullest extent of the law."

Dr. Thomas Lynch at the National Defense University told ABC News Thursday that beyond providing a potential intelligence windfall, Abu Ghaith's capture meant one of the more dangerous members of core al Qaeda is now out of play.

"Abu Ghaith is one of ten guys left from al Qaeda core that have the financial ties and reputation who might have been able to get the old band back together to execute spectacular international terror attacks," he said.

Ghaith will remain in federal custody until his next court hearing in early April.

ABC News' Lee Ferran and Rym Momtaz contributed to this report.

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