A slightly more credible input, albeit from POTUS ...
Speaking later in the White House briefing room, Obama said it was “too early for us to be able to guess what the intentions were of those who might have launched” the missile. “What we know right now, what we have confidence in saying right now, is that a surface-to-air missile was fired, and this is what brought the jet down. . . . That shot was taken within territory that was controlled by the Russian-backed separatists.”
http://www.washingtonpost.com/world/...d23_story.html