Informants

From 9/11 Encyclopedia:

Based on the information of german intelligence files, Mamoun Darkanzali (->), was one of the first few informants of the CIA, 
who was connected with the hijackers, since 1998. After September 11th, Mamoun Darkazanli Import-Export Company 
(Hamburg, Germany) was put on the frozen account list. 
German authorities interrogated Darkazanli (->), but after a while they concluded that he wasn't involved in the attacks. 
(-> Spanish connection) One might speculate, if "some of the former 'informants' just later turned into 'hijackers'?" 
Other informants: Atif Ahmed 
http://www.counterpunch.org/levich0925.html

September 25, 2002 Case of the Missing Terrorist Solved...Not! by JACOB LEVICH (->) "...But the FT story may raise more questions than it answers. ...Atif Ahmed, you'll recall, was nabbed by Scotland Yard detectives in November, 2002, after the FBI said it found evidence suggesting he was a co-conspirator with accused "20th hijacker" Habib Zacarias Moussaoui.

In subsequent months, Moussaoui has repeatedly and insistently identified Ahmed as a key player in the 9/11 conspiracy -- and as a British mole within Al Qaeda. Yet the mainstream press declined to investigate, and the elusive Ahmed vanished from the public record in what felt eerily like a press blackout.

Cia-Moles http://www.usatoday.com/news/attack/2002/06/03/cia-attacks.htm 
June 06, 2002 U.S. had agents inside al-Qaeda

Collins, Aukai from his book "My Jihad": "The little scrawny guy was taking flight lessons in Scottsdale, right up the road from my house.
I'd known some of his roommates before Ghareeb had starting talking to him and was good friends with one of them. 
They were all taking flying lessons, and my friend was already rated for twin-engine aircraft. <...>
I was still working for the Bureau at this time and reporting to Andy <*his FBI contact - Andres Sanchez*> regularly. 
Both the FBI and Andy were fully aware of all the Arabs whom Ghareeb and I had contact with, including the scrawny little guy whose name is widely now known: Hani Hanjoor. Hani Hanjoor would get his pilots license in 1999 and would fly an American Airlines plane into the Pentagon.

They were hardly "deep cover sleepers" as the FBI is calling them now. They lived very openly, and although I had no idea what some of them would eventually do, they made no secrets about what they thought or believed." ("My Jihad, p213-4) Introduction to the book: http://rp.publicationsunbound.com/samples/sample1585745650.pdf 

Aukai Collins claimed, he observed Hani Hanjour,, which was denied by the FBI some months ago: http://abcnews.go.com/sections/wnt/DailyNews/FBI_informant020523.html

"FBI Was Warned of September 11 Hijacker May 23 "...A paid FBI informant told ABCNEWS that three years before September 11, he began providing the FBI with information about a young Saudi who later flew a hijacked passenger plane into the Pentagon..." Aukai Collins, the informant, said he worked for the FBI for four years in Phoenix, monitoring the Arab and Islamic communities there. Hani Hanjour was the hijacker Collins claimed to have told the FBI about while Hanjour was in flight training in Phoenix. Twenty hours after ABCNEWS first requested a response, the FBI issued an "emphatic denial" that Collins had told the agency anything about Hanjour, though FBI sources acknowledged that Collins had worked for them..." Aukai Collins -the book http://rp.publicationsunbound.com/samples/sample1585745650.pdf

Randy Glass: Early August 2001: Randy Glass, a former jewel thief turned government informant, later claims that he contacts the staff 
of Senator Bob Graham and Representative Robert Wexler and warns them of a plan to attack the WTC, but his warnings are ignored. 
Glass was a key informant in a sting operation involving ISI agents trying to illegally purchase sophisticated US military weaponry
in return for cash and heroin (see June 12, 2001). 
Glass claims that before the sting operation ended in June 2001, one Pakistani operative named R. G. Abbas made three references to imminent plans to attack the WTC. In one meeting held in New York City in 1999, Abbas pointed to the WTC and said, "Those towers are coming down."
Glass caught this meeting on tape (see July 14, 1999). In October 2002, Glass testifies under oath before a private session 
of the Congressional 9/11 inquiry. He states, "I told I have specific evidence, and I can document it." http://www.cooperativeresearch.org/completetimeline/AAadvanceinfo.html

Abdussattar Shaikh (->): The landlord regularly prayed with Khalid Almihdhar and Nawaf Alhazmi and even helped one open a bank account. He was also, sources tell NEWSWEEK, a "tested" undercover "asset" who had been working closely with the FBI office in San Diego on terrorism cases related to Hamas. A senior law-enforcement official told NEWSWEEK the informant never provided the bureau with the names of his two houseguests from Saudi Arabia. Sources: http://www.msnbc.com/news/805186.asp?cp1=1

->GZ (passive) http://forums.delphiforums.com/n/mb/message.asp?webtag=ground_zero2001&msg=1472.1