The official investigation concludes that flight MH17 was shot down by a Buk missile. It did not address the question of who fired it.

I think it is pretty clear that the Russian proxy rebels fired it, thinking they were firing at a Ukrainian fighter plane. The rebels did not have fighter planes, so Ukraine's army would have had no occasion to make that sort of mistake.

In an apparent coverup, someone operated on the flight captain's corpse, removing some of the foreign objects that killed him. The only ones in a position to do that were the rebels.