[on photos of FBI agents combing for evidence]
After seeing the pentagon research site, i noticed it spoke of a C130 possibly dropping planted debris-- ala Northwoods fake debris release scenario.
longshot theory: the FBI agents combing the area FAR from the pentagon were 'collecting' any faked, dropped, plane parts that might have been damning -- if someone else found them -- photographed them -- or maybe covering evidence regarding light-pole shenanigans.
it appears that the consistent job performed by the FBI was to suppress evidence - so this would be in keeping.
I welcome any other theories to explain what FBI agents were doing out there with paper bags.