51.   Police were investigating the causes of the accident.

52.   Tenet will also face questions from the Senate Veterans Affairs Committee, which is investigating the cause of the mysterious ailments reported by thousands of Gulf War veterans.

53.   The agency, which has been investigating the cause of the accident, said today it will ask prosecutors to pursue the case.

54.   The Air Force is investigating the cause of the accident.

55.   The cause is being investigated as officials sift through contradictory witness statements and fragmented recollections of those terrifying seconds.

56.   The Brady Commission, appointed to investigate causes of the crash, concluded that selling pressure from portfolio insurers increased the general panic and contributed to the market meltdown.

57.   The cause is being investigated by company and fire officials.

58.   The company is investigating the cause of the leak, the Tonen spokeswoman said.

59.   The company said Wednesday that it was continuing to investigate the cause of the irregularities.

60.   The cause is being investigated by Cargill, its equipment supplier and insurer.