If the Mansi have stolen something, for example, knives, cameras, flashlights, they don't want it to be known. And they may have completely erased their traces. After all, they're master hunters... and trail experts. They can destroy their tracks in the snow. And if there were unusual sounds and images on the mountain on the night of the incident, the Mansi must have noticed it. And by daylight they must have gone there. And in particular, they must have found the two Yuri and the tent. And they must have taken some useful items and left. Of course they couldn't admit it. Because they were afraid of being killed. They could be considered murderers.