Bomb? Onboard fire?
Something I keep looking to occur one day, if it hasn't already (e.g. the flight that crashed in the N.E. with control surface failure) is malicious avionics code uploaded, causing a fatal over-control or oscillation with the aircraft's flight control surfaces.
It was reported ISIS was taking credit and claiming to have used their "brains", but wanted to keep how they did it a secret.
The third thing may have been a rupture of the main cabin. But it would be rare that that would lead to total destruction of the airframe.
Just my 3 cents...
Missile and Obama Admin protecting Hillary’s sale of stinger-type technology to terrorists?