The gov coverup it is expected. Remember that was during the peak of the communist regime in URSS and these kind of events they were always trying to coverup with more lies. The communist regimes had a powerful propaganda and disinformation machine. Sometimes the members of this machine are so obedient and scrupulous in doing their job, that even go way beyond the instructions they receive, looking only for theirown personal goals to climb the ladder in the party for a better position that could bring them more privileges. Let me search for that movie and will post here the link. Is really good.