51.   Fire officials have not been able to determine the cause of the first fire, but say the second was deliberately set.

52.   Federal investigators were on the scene Sunday, but said they would be unable to determine a cause for weeks.

53.   Fire marshals investigating the fire Sunday had yet to determine its cause, said Charles G. Hendry, chief of the Hempstead Fire Department.

54.   Fire officials said that they had not determined the cause of the blaze, but that it was not believed to be arson.

55.   Francois Muguet, the state prosecutor in Dunkirk, said his probe would proceed in an effort to determine the cause of the illnesses.

56.   Ground control began evaluations to determine the cause.

57.   Gilbert police also asked the federal Bureau of Alcohol, Tobacco and Firearms to determine the cause.

58.   He added that pathologists would have to determine the cause of death of one victim who had no visible bullet wound and was not found wearing a plastic bag.

59.   He assumed these must be defects or electronic glitches, and spent years trying to determine their cause so the problem could be corrected.

60.   Hart said that investigators may need up to a month to analyze all the evidence and determine the cause of the accident.