1.   A principal theory is that one or more oxygen generators the jet carried in its forward cargo hold accidentally activated.

2.   A possible source of that smoke, according to investigators, was three aircraft tires, carried with the generators in the forward cargo compartment.

3.   In addition, analysis of the tire and pieces of two canisters indicate fire was present in the forward cargo hold.

4.   Investigators believe the explosion erupted near the forward cargo area of the plane.

5.   More wreckage has been retrieved from the front section of the airplane, including a bin from the forward cargo hold where investigators suspect a bomb was placed.

6.   Now that the forward cargo hold has been eliminated, investigators theorize that a bomb exploded on board, possibly in seats above the center fuel tank.

7.   On Sunday, a door to the forward cargo hold was retrieved by divers and taken to Washington for forensic testing, sources said.

8.   Over the weekend, they concluded that a bomb could not have been hidden in checked luggage in the forward cargo hold.

9.   Privately, they lean toward the theory that a bomb exploded in the forward cargo hold, which contained passenger luggage.

10.   The blanket is located directly behind the forward cargo control unit, Hall said.