1.   Two hijackers used fake explosives to commandeer the airliner.

2.   Authorities would not comment on the call, but Attorney General John Ashcroft confirmed at a news conference that the hijackers had indeed used knives.

3.   A. Officials have acknowledged the possibility that some hijackers may have used false identities and that investigators may not know their real names.

4.   But if the hijackers used small blades that were permissible to carry on, why blame the screeners?

5.   In Frankfurt, even the departure-area stores have been told to stop selling Swiss Army knives or other souvenirs that could be used by hijackers.

6.   Investigators believe the hijackers used box cutters in the attack because their plastic handles would not set off metal detectors at airport security checkpoints.

7.   Investigators say thieves and hijackers use many systems for fencing their loot, depending on the marketability of the stolen products and the relationships they have established with fences.

8.   The hijackers used similar knives to take over control of the four planes hijacked last Tuesday.

9.   The hijackers used box cutters and short knives to terrorize passengers and crew and seize control of the aircraft.

10.   The hijackers apparently used little violence, except perhaps to tie up some of the crew members.