A fire in the engine is not enough to turn a 737 into a huge burning fireball that crashes within 20 seconds.
Regarding the missile theory: if it was a missle, it was probably accidential. The majority of passengers on board were Iranian citizens.
Regarding the missile theory: if it was a missle, it was probably accidential. The majority of passengers on board were Iranian citizens.
Unless it was a non-Iranian missile, or a rogue actor.
(At this point, it's all speculation)
* Precisely for reason above
From a suggested twitter video. No affirmative source yet.