Suleiman Abu Ghaith should, at least theoretically, bring to light the history of Iran keeping certain key AQ members under 'house arrest' since 9/11. But why, some people may ask, would they do it? After all they are Shia, AQ is Sunni.
While the answer may be obvious to the Jessica Chastain type characters in the CIA--perhaps as leverage to keep the west from attacking and bide time for the nuclear program, the bigger question may be whether Iran had any foreknowledge of 9/11 (as a federal judge in 2011 ruled in a civil trial). Such a revelation, if true, is certainly not something that would make headlines at the moment for obvious reasons, nevertheless it might explain a lot about the War on Terror in general.
Poking around on this subject invariably unearths the name Thirwat Shehata. A lawyer and senior member of Zawahiri's Egyptian Islamic Jihad (his resume is deep), he was/is among the house arrestees in Iran. He was also one of the senior members of EIJ that was believed to be operating in Iraq before the invasion in 2002-03, as mentioned by Tenet and Cheney (as casus belli for the attack). His presence there is disputed, but one thing is sure, he's still around and hasn't been caught and is known as a right-hand man to Zawahiri.
But there's more than just safe harbor in Mullah-ville. Shehata married the sister of Mahmoud Jaballah, who operated in Canada until he was picked up after 9/11 and placed in their "Gitmo North' without charges. A judge released him and fellow detainee Mohammed Mahjoub to 'house arrest' in 2007 although the Canadian CIA (CSIS) has been closely monitoring them since. Mahjoub was connected to "Vanguards of Conquest" (possibly the second in command) and was associated with Essam Marzouk, also a VoC member. The Vanguards were associated with Zawahiri and Mohammed Atef, who was working on a project when he was droned in 2001. Abu Ghaith threatened America with millions of deaths via WMDs in 2001. So yes, surely the FBI was very interested in what he might know.
This blog did a piece on the Canadian connection back in 2008, tying them to suspected AQ figures Mohammed Loay Bayazid, one of the founding members of AQ, and Muburak al-Duri, an Iraqi whom the 9/11 Commission called a WMD procurement person for bin Laden. Despite all kinds of circumstantial evidence placing these two in connection with AQ or EIJ members, neither have ever been arrested. Both deny any involvement with terrorism, so maybe the FBI believes them, or maybe there's an inconvenience factor in play.
At any rate, those not as smart as the Jessica Chastain character might see the dots between AQ, Iraq, Iran and WMD--and even the new Muslim Brotherhood ascension in Egypt--and try to connect them. Some might even see the "death to America, death to Israel" scribbled in the anthrax letters after 9/11 as the calling card it was intended to portray, ie, don't mess with us, we have sleepers. Which would line up with keeping AQ figures in-country under house arrest. Sort of like keeping UBL locked up in a house in a Pakistani military garrison town. Insurance. And what about Benghazi? Any loose connections?
Or maybe it's all too convenient and Halliburton and friends are still the real enemy. As usual, mystery and confusion reigns.