11.   Air accident investigators are now trying to establish what caused the crash.

12.   Accident investigators are now trying to piece together what happened.

13.   Fire brigade investigators are still trying to discover the cause of the explosion and any chain of events which might have led up to it.

14.   Investigators are still trying to piece together the events leading up to the blast, which destroyed the ground floor of the house on the outskirts of Wigan.

15.   Although investigators sometimes try to contact complainants by going to their homes, Perez said she did not think the detective went to Mesquite.

16.   Among other things, investigators are trying to determine whether Pecard falsified military records, was absent without leave and impersonated federal agents.

17.   An Israeli police spokesman said investigators were trying to determine whether the killing was criminally motivated or was an act of terrorism.

18.   And the surest way to do that, Moriarty added, is by retrieving the sales record from Tattered Cover, which investigators have tried through a search warrant.

19.   As investigators try to identify the bodies on the Marsh property, the community is looking for answers.

20.   A key factor in many small-plane crashes is pilot fatigue, Barr said, so investigators will try to reconstruct his final days.