Coincidence? A look at conspiracy theories Pictures A look at conspiracy theories Almost immediately after TWA flight 800 exploded off the coast of Long Island, N.Y., killing all 230 people on board, theories began to emerge about what caused the disaster. For some, the findings of the NTSB investigation - which concluded after a four-year probe that the crash occurred because a spark ignited the center fuel tank - were never satisfactory. Among the theories: the plane was shot down by a missile -- either as a terrorist attack or a Navy exercise gone wrong. These theories were recently reinvigorated by a group of former investigators who are convinced a TWA Flight 800 was brought down by an outside explosion and have petitioned the government to reopen the probe, citing new evidence. Read more:TWA flight 800 gets another look 17 years later