Mr. GG2 who is a pilot and also used to build planes at Boeing said that the described gyration of the plane is indicative of a wing shearing off. He thinks likely due to bomb also.
Could be a wing; that would be a bomb in the fuel there. But that is harder to get to and the fuel is much more protected than people think. It would also require a mechanic with a lot of know-how to get something in there. And greater chance of detection, since inspectors come along after.
The tail is more likely, IMHO, in that it’s weaker and that is where the storage area for thing loaded onto the plane by airport staff (e.g., food/drinks) are.
Any control surface (tail or wing) loss would give you roughly the same effect.