Even four years after the World Trade Center fell, 9/11 is still breaking news, especially for the makers of the four-hour documentary "Inside 9/11." (search)

Producers say the film — which airs in two parts on The National Geographic Channel (search) on Sunday and next Monday — is the most complete compilation of the terror attacks and aftermath so far.

To keep it that way, the filmmakers will be scrambling this week to include the latest details as they continue to emerge.

"The good thing is that our team has been on the case for the last year and we will cover most of the stuff that's come out in the last few weeks," says executive producer Michael Cascio.

Chief among the last-minute additions will be references to the claim made last week that U.S. military officials had identified four of the 9/11 highjackers — including ringleader Mohammed Atta (search) — more than a year before the attacks, but did not pass on the information to the FBI.

"Inside 9/11" is going to be "very unpleasant for some people in this [current] administration and in the last one," says Michael Scheurer, the former senior CIA analyst who in 1996 created a secret unit for tracking and eliminating Usama bin Laden.

"Americans are going to come away from this [telecast] wondering what their leaders were doing from 1993 to 2001."

Scheurer is one of dozens of 9/11 "witnesses" who appear in the film and try to put the events of that day in perspective with the warning signs leading up to the attacks and how the world has changed in their wake.

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