21.   The apparently growing interest of forensic police experts in the dead suggested that the bodies themselves might hold clues that could help identify the bombers.

22.   The black box, or cockpit recorder, often holds critical clues for investigators looking for the cause of fatal plane crashes.

23.   The direction of the wind may hold the clue to the mystery of why cancer rates are sometimes higher near powerlines.

24.   The envelope and its contents could hold important clues for the investigation, including fibers, fingerprints or human DNA.

25.   The earliest pieces to part from the plane are most likely to hold clues to the cause of the blast.

26.   The goal is to find four elusive Riddler icons, hidden throughout the Web, which hold clues to an intricate riddle.

27.   The player receives faxes holding vital clues.

28.   The scientist peered into the test tube of Lake Tahoe water, which held clues to the future of one of the greatest lakes on earth.

29.   The weather may hold a clue.

30.   These Broadway performances hold no clue to his future, but they say a lot about his past.