At the moment there are only two pieces of solid information. The video shows an in-flight fire with some break-up already happening (looking close it is possible to see at one point glowing pieces shredding) and just before the final impact (but still in the air) there is a major flare-up. The post-crash photos show clear evidence for external shrapnel damage on a section of the fuselage (the damage seen on the VS and the engine exhaust cowl is not conclusive, those could have happened during ground impact).
The combination of the above is EITHER the result of a catastrophic uncontained engine failure, OR a missile strike, full stop. In principle, design and certification should preclude the former, but it still does happen, cannot be ruled out at this stage.
While the evidence is certainly suspicious, knowing Iran well (have just been there last October) I find an accidential missile hit rather unlikely. While panic and incompetence under the circumstances is entirely plausible, Iran is a very tightly controlled society, and the news of such a blunder would have reached the highest levels very rapidly. The accident happened in the dark, and the first reports show burning wreckage in darkness. Had it been a missile launched by Iranian forces, the area would have been cordoned off and no photos with incriminating evidence would have been permitted to surface, especially not on government controlled news outlets. There may be incompetence among the military, but certainly not among the news censors.
Last edited by andrasz; 8th Jan 2020 at 10:17.