11.   Some investigators and academics now suspect that the elusive bomber may have intellectual roots in the less-exact world of the social sciences, like sociology or anthropology.

12.   Since then, the supersonic bomber has had a history of design problems, cost overruns and fatal crashes.

13.   The bomb consisted of four pipe bombs packed with nails and screws to be detonated by toggle switches the bomber would have to throw by hand.

14.   The bombers had to know, had to have been targeting children, Welge says.

15.   The bombers have yet to be identified and security officials fear whoever organized the attack remains free to strike again.

16.   The stealth bombers have returned home, several arriving Wednesday, though their pilots stayed to rest at Diego Garcia, a British base in the Indian Ocean.

17.   Three years later, the business that the two Oklahoma City bombers had here is still unknown.

18.   Bombers have since attacked military bases in Londonderry and nearby Ballykelly.

19.   Radio reports said the bomber had a work permit for Israel, and in recent months was employed at a restaurant in the central Israeli town of Rishon Lezion.

20.   Suffering losses, the U.S. bombers had to move higher for safety, cutting their accuracy.