61.   Air Force officials said they had no idea what caused the accident.

62.   But Dewayne Tully, a Police Department spokesman, said the police could not say whether the lack of street lights caused the accident.

63.   But if there is clear evidence that the accident was caused by gross negligence that rises to criminal conduct, prosecution may be justified.

64.   But officials said it was too early to know whether the pole broke during the fall or whether a break caused the accident.

65.   But it is not always drivers who cause the accidents.

66.   But it is unclear what caused the accident.

67.   But that did not lessen determination in France to establish whether the chase by paparazzi had helped cause the accident.

68.   But the drivers believe it also causes accidents.

69.   But the snow was laced with a nasty touch of rain, and the blend slowed cars and caused many accidents.

70.   But the tests left investigators little closer to determining what caused the accident.