New York (CNN) -- Al Qaeda propagandist Sulaiman Abu Ghaith had a long plane ride last week to New York and an American jail cell located blocks from ground zero of the September 11 attacks.
He filled that time, in part, by talking to U.S. investigators. It was an odd end to a journey that began just weeks earlier in Iran.
Abu Ghaith, for reasons still unclear, left Iran and entered Turkey using a forged Saudi passport, Turkish media reported. The CIA tracked him to a Turkish hotel room.
He was detained by Turkish officials in early February, but they refused for a month to turn him over to the U.S.
Instead, Turkey expelled Abu Ghaith and put him on a plane to Kuwait, where he was born, sources said. U.S. law enforcement took him into custody during a stopover in Jordan. Members of HIG -- the High Value Interrogation Group, which includes the CIA -- were also involved in the operation.
Abu Ghaith apparently wasn't quiet during his overseas flight with U.S. authorities. The conversations, confirmed by a U.S. official with knowledge of them, are expected to be part of the government's case to prove Abu Ghaith helped conspire to kill Americans and recruited members for al Qaeda.
The Justice Department and FBI declined to comment on whether or when Abu Ghaith was read his Miranda rights after his arrest. However, intelligence experts say that is required if prosecutors intend to use his lengthy statement during trial.
"That would be the way it was done," says Mitchell Silber, an executive managing director with the security firm K2 Intelligence and the New York Police Department's former director of Intelligence analysis.
Sources and intelligence experts told CNN it's questionable how helpful Abu Ghaith, one of Osama bin Laden's sons-in-law, could be in terms of current intelligence, because he has been out of the loop for years. He has lived in Iran since 2002, mostly under house arrest.
"He's a low-level target with high political value," Silber told CNN. "His main value would be (if he's) able to help quantify and assess the former top al Qaeda leaders with him under house arrest in Iran," Silber says.
Silber added the U.S. would want Abu Ghaith to "describe the nature of the Iranian treatment of them," including "how adversarial the relationship is between Iran and al Qaeda." There is concern former al Qaeda leaders in Iran could rise to power again.
But the relationship between the predominantly Shiite Iranians and the largely Sunni al Qaeda members is a complex one.
Just how do the Iranians view al Qaeda? Do they see opportunities for cooperation? Or is the extreme Sunni philosophy of the group too much for them? It's something investigators would like to know, and Abu Ghaith may have insights.
On Friday, the fiery former al Qaeda spokesman walked into federal court with his hands cuffed. He was only about a mile from ground zero in the very country he had targeted in multiple video messages, warning Americans they would be attacked again after 9/11 by "airplane storms" and biochemical attacks.
At his arraignment, his cuffs now removed, a not guilty plea was entered on Abu Ghaith's behalf by Philip Weinstein, the attorney appointed to represent him. Abu Ghaith told the court, through an Arabic interpreter, he had no money to pay for a lawyer.
Prosecutors didn't reveal what Abu Ghaith had said to them, only telling the court he had made an "extensive statement" after his arrest that filled 22 pages.
The charges in the indictment were sealed until his arrest.
He is being held without bond until his next appearance in April. No trial date has been set. If found guilty, Abu Ghaith faces life in prison.