81.   Investigators are awaiting autopsies by the Tarrant County Medical Examiner to determine the cause of death.

82.   Investigators from the National Transportation Safety Board were trying to determine the cause.

83.   Investigators have not determined a cause or whether human error was a factor, he said.

84.   Investigators were careful to say that they have not determined the cause of the crash and that there is no indication that the pilots did anything wrong.

85.   Investigators were interviewing tenants on Monday and were still trying to determine the cause of the fire.

86.   Investigators had not determined the cause of the accident Saturday.

87.   Investigators were still trying to determine the cause of the fire Monday evening.

88.   Initially, the Air Force closed its investigation after saying it could not determine the cause of the crash.

89.   Investigators have still not determined the cause of the crash, or ruled out terrorism.