interviews wrote summaries that they then submitted. Witnesses were not asked to review or correct the summaries. Included in some of the witness summaries were drawings or diagrams of what the witness observed. Within days of the crash, the NTSB announced its intent to form its own witness group and to interview witnesses to the crash. After the FBI raised concerns about nongovernmental parties in the NTSB's investigation having access to this information and possible prosecutorial difficulties resulting from multiple interviews of the same witness, the NTSB deferred and did not interview witnesses to the crash. A safety board investigator later reviewed FBI interview notes and briefed other board investigators on their contents. In November 1996, the FBI agreed to allow the NTSB access to summaries of witness accounts in which personally identifying information had been redacted and to conduct a limited number of witness interviews. In April 1998, the FBI provided the NTSB with the identities of the witnesses, but due to the time elapsed, a decision was made to rely on the original FBI documents rather than reinterview witnesses. Further investigation and analysis Examination of the cockpit voice recorder (CVR) and flight data recorder data showed a normal takeoff and climb, with the aircraft in normal flight before both abruptly stopped at 8:31:12 pm. At 8:29:15 pm, Captain Kevorkian was heard to say, "Look at that crazy fuel flow indicator there on number four... see that?" A loud noise recorded on the last few tenths of a second of the CVR was similar to the last noises recorded from other airplanes that had experienced in-flight breakups. This, together with the distribution of wreckage and witness reports, all indicated a sudden catastrophic in-flight breakup of TWA 800. Possible causes of the in-flight breakup Investigators considered several possible causes for the structural breakup - structural failure and decompression, detonation of a high-energy explosive device, such as a missile warhead exploding either upon impact with the airplane, or just before impact, a bomb exploding inside the airplane, or a fuel-air explosion in the center wing fuel tank. Structural failure and decompression Close examination of the wreckage revealed no evidence of structural faults such as fatigue, corrosion, or mechanical damage that could have caused the in-flight breakup. The breakup also could have been initiated by an in-flight separation of the forward cargo door like the disasters on board Turkish Airlines Flight 981