Technically, according to international agreements, the maker of the aircraft is supposed to LEAD the investigation. The Russians had no right (according to the agreement), to take any pieces of the aircraft, or any possessions of the passengers; or to remove the bodies.
The CRIME SCENE has been totally destroyed .. and my best guess would be that it was on purpose so nobody could see the damage to the aircraft in order to make an accurate account of what hit the aircraft and where.
And where are the Russian & Ukrainian Orthodox churches in the midst of this humanitarian crisis??
(Not to expect a real answer, given that “Pope Vladi” probably gives the marching orders from Moscow.)