Since the airliner was flying at cruising speed and altitude, it was far beyond the reach of simple to use manpads, the shoulder launched anti-aircraft missiles that Muslim terrorists have acquired and used successfully at times. Instead, the large and sophisticated Russian Buk missile system with high altitude reach has been identified as the culprit, a weapon that requires a trained crew. That means that either Russians or Ukrainians shot down the airliner.
Since the airliner was shot down over rebel held territory, the Ukrainian army must be excluded. Logically, that leaves Ukrainian separatists and Russian as responsible.
Notably, what we refer to as Ukrainian separatists includes Ukrainians, but they are primarily organized, led, and controlled by Russian army special forces, paramilitary, spies, and soldiers for hire. They have at the ready or can assemble or access crews with the training to operate Buk missile systems.
Independent observers reported that Russian crews drove mobile Buk systems with SA-20 missiles across the border to separatist held territory. Separatists are also known to have captured a Buk launcher loaded with SA-11 missiles when they took over a Ukrainian army base.
Notably, a Buk missile was apparently used a few days ago to shoot down a Ukrainian military transport. Social media postings by the separatists bragged of shooting down another Ukrainian transport, but those postings were deleted once it was realized that a foreign airliner had instead been downed.
At the very least, those who shot down the Malaysian airliner are Ukrainian separatist crews under the control of Russian special forces. Or, the crews may have been Russian, using a launcher and missiles provided by the Russian military.
Supposedly, US intelligence will be able to determine what type of missile was used and precisely where it was launched from. That will tell us whether a Russian supplied missile and crew was guilty, or if a missile captured from Ukrainian stocks was used.
That the Russians immediately grabbed the flight recorders indicates that they were closest to the events, closest to those responsible, and close to where the aircraft fell. Since this was near the Russian border, it may even be that the Russian military itself shot down the airliner down from Russian territory.
I mean you can impute blame for the deaths on Putin because of his encroachment on the Ukraine, but that seems different from a direct order from Putin to shoot the airliner down.
Putin isn't stupid, I don't think. I really don't see how Putin would see this as helping him in what he's trying to do while trying to keep international economic sanctions minimal.