It seems with what we're hearing in the news indicates that a proper independent investigation is increasingly unlikely. Looting of the bodies and refusing access to the site for the proper authorities is inexcusable.
Whether or not the action by the rebels is orchestrated by Moscow remains to be seen, however the rebels need to be reigned in.
It's more than likely that the Americans know exactly where the missile came from and probably who fired it. This information will no doubt be shared with the countries directly affected. The question is what will the governments do about it?