A 737-800 went down just outside of Tehran last night. Looking at the video of the airplane falling (mid-way through CNN's brief) it's on fire in a big way. 1/3 of the passengers were Canadian.
This was not a mechanical issue - it was on FIRE as it was falling from a catastrophic incident. No issues raised, no emergency calls, just 'poof' - loss of data.
Guessing from the video and my own military experience, it looks like it was shot down. Some of the still images from today at the crash site I can see parts with 'small holes' - punching in...not out. Some on the tail section, some on an engine shroud, some parts look like it was hit with a shotgun at close range.
It could just be post-crash damage as I'm not a crash investigation expert. But, seeing images from the crash in Ukraine and what I've seen personally from battlefields, it raises a lot of questions. Hopefully, we'll know more soon.