It would seem the the FBI would need to have some other knowledge to make such a statement.
Switiching from FOX, MSNBC and CNN. Many eye witnesses reporting heard loud noise, pieces coming off of plane while plane spiraled down. One lady was very specific that she saw fire on a wing, and saw the wing fall off.
Some FAA guy saying an explosion can result from some mechanical problems. Also, Neal Cavuto again bringing up issue of baggage search, which no one seems to want.