No wonder communist governments hide information that they are not interested in making public...

Obviously, not. For the communists, everything had a scientific explanation. They did their best to ban religion, so they could not tolerate people starting to believe in spirits. Especially as, at first, people in the are were not interested in UFOs and parallel universes. Many believed the spirits in the forest were those of the recently dead, that wander in between realms for 40 days, as this explanation was too close to religious practices. In the Christian Orthodox Church there's a special ceremony to mark the passing of 40 days since somebody's death, when food is offered for the spirit of the departed and his clothes are given to the poor.