To me, it appears that the HS and VS had to be damaged before the separation of the tail section. Had that section separated first, I don't think sufficient forces would have been generated to do the damage. The VS appears to have split which could only happen if the aft mounting points were pushed rearward relative to the front mounting points.
My sequence would be HS/VS failure (reason
TBD), HS tore off tail cone/APU, tail section is torn off by tumbling or spinning, fuselage rear section now has an open end and is torn apart by aerodynamic forces up to the stronger wing box, remainder of aircraft catches fire and falls vertical, mostly intact.
While this doesn't rule out foul play, it does make it less likely. A bomb in the passenger compartment or in the cargo hold is probably not going to cause failure of the HS and VS.