Mauersegler just down the holes for center lugs circular bendings are clearly seen. Teared our "ears" are lower. I see it like this (thanks for picture)
Now it's time for some crazy guess...
1) Some person who was allowed in by corrupted security, visit plane overnight and placed something at the top of center of HS.
2) Let's us assume it was not bomb, but some mechanical device, thus troubles with identifying case of disaster.
3) Device pushed HS down at the end of climb
4) APU cone separated, as shown above, broken fuel line spill some kerosene, electric sparks ignite central tank.